SI, Marathon Reviews, and Group OH for the 2nd Midterm

Here are the schedules for the remaining SI sessions, the SI Leaders' Marathon Reviews and my Group OH.

Thursday: Jeffrey: 6-7:30pm HH104

MARATHONS:
Thursday: Suzanne: 7-10pm Bio LH100
Sunday: Jeffrey 2-5pm Bio LH100

Group OH
Monday: 6:30 - ?? Bio room 21

Homework Assignment #4

HW #4 is now available on Mastering Biology.

Plant Diversity- Ferns

Ferns are examples of the first vascular plants.

Readings From Textbook

pages 610 - 617


Lecture Video: http://mediacast.ttu.edu/Mediasite/Play/bd420633464742c09ae19a749929d3661d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b



Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- discuss the components of the vascular system
- discuss the advantage of a having a vascular system
- diagram the life cycle of a fern
- discuss the morphological and physiological characteristics of ferns
- discuss the characteristics of ferns that makes them considered to be advanced relative to mosses but primitive relative to the gumnosperms
- discuss how the morphological and life history characteristics limits their size and geographic distrubution

Homework Assignments 2 and 3

The second homework assignment, covering cellular respiration, is currently available on the MasteringBiology website.  The due date for this assignment is Saturday March 2nd by 11:59 PM (really, I have set the time correctly!!).

The third homework assignment, covering primitive plants, will become available on Wednesday February 27th.  The due date for this assignment is Monday March 4th by 11:59 PM.

Keep an eye out for my final homework assignment that will be due before the exam on Tuesday March 5th.

Homework #1- Update

Hello Everyone,

Thanks to everyone who sent me a message letting me know that I had set the completion time for HW #1 for 11:50 AM rather than 11:59 PM as I intended.  Because so many of you contacted me I am unable to respond to all of you individually.

The purpose of the homework problems are to encourage you to spend more time studying the material.  Because it is not fair to punish anyone for a mistake that I made, ALL STUDENTS WILL RECEIVE THE FULL 12 POINTS FOR THE FIRST HW ASSIGNMENT.

Recent Research about Global Carbon Cycle and Climate Change

Melting Permafrost: Scientists Warn of Dangers of Trapped Carbon

http://abcnews.go.com/International/melting-permafrost-scientists-warn-dangers-trapped-carbon/story?id=18569156

Plant Diversity- Algae and Mosses

Plants are interesting to me because they are so different from us and the organisms that we are most familiar with (mostly animals). At first these differences will cause unfamiliarity, but eventually you will not be so bogged down by learning new vocabulary and you will hopefully come to realize that plants are more interesting than you might have thought (and besides, no plants means no dorritos, french fries, or beer?).


Lecture Videos: http://mediacast.ttu.edu/Mediasite/Play/970d298352ea462587ecf88d87bae3421d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


http://mediacast.ttu.edu/Mediasite/Play/bd420633464742c09ae19a749929d3661d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b





Readings From Textbook

pages 600 - 610.

Further Viewing

1) Here is the slideshow that I will use in class for the final three lectures.

http://www.slideshare.net/secret/DBv71wnKTH1YBN

2) Here is a powerpoint presentation from a group called "world of teaching" that covers plant diversity? There are many "quiz questions" that should be helpful to look at.

http://www.worldofteaching.com/powerpoints/biology/Plant%20Divisions.ppt

Primitive Plants

Expected Learning Outcomes

A the end of this course a fully engaged student should be able to

- functionally define a plant
- discuss the characteristics of a primitive plant such as Chlamydomonas
- diagram a life cycle of a human
- diagram the life cycle of Chlamydomonas
- distinguish between oogamy and isogamy
- discuss the evolutionary advantage of multicellularity, diploid dominance, and oogamy

Transition to Land

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- discuss the problems plants face when moving to the land
- discuss the characteristics of the ancestor of land plants
- diagram the life cycle of a moss
- discuss the morphological and physiological characteristics of mosses
- discuss the characteristics of mosses that makes them considered to be advanced relative to primitive plants but primitive relative to the ferns
- discuss how the morphological and life history characteristics of mosses limits their growth and geographic distribution

Mastering Biology: Homework Assignment #1

On-line homework will account for a portion of your grade for BIOL 1404. You will need to be enrolled in the MasteringBiology website. Below is a message from Dr. Dini explaining what you need to do in order to enroll. Students who took BIOL 1403 here last semester should be familiar with the system. Those of you who are new to BIOL 1404 at Tech might check with fellow students about the on-line homework because they are likely to know much more about it than I do.

The first assignment will be due by 11:59 PM on Monday February 25th. I have posted the first assignment that relates to Photysynthesis

Mark McG

Dear Student:
In this course you will be using MasteringBiology™, an online tutorial and homework companion to your textbook. It may be useful to print this sheet before you attempt to register.

Students who were enrolled in the on-line homework for BIOL 1403 no longer need their access code, as they are already in the system. They just have to click on the button to enroll in a new course, and it’s done. They merely need the new course’s ID #. New students DO need an access code (unless Mastering Biology was used wherever they took BIOL 1403).


What You Need:
P A valid email address
P A password that you make up (must have 8 characters; at least 1 of these must be a letter and at least one of these must be a number.) If you already have a Pearson Education account (you probably do if you took BIOL 1403 at TTU last semester of if you use MasteringPhysics or MyMathLab), just use the same password.
P A student access code (Comes in the Student Access Kit that may have been packaged with your new textbook or is available separately in your school’s bookstore. Otherwise, you can purchase access online at www.masteringbiology.com.)
P The ZIP code for Texas Tech University: 79409
P The Course ID:  MBMCGINLEY45100
P Your TTU ID#: _____________________ (Please DO include the R at the start of your number.  Memorize this #, if you have not already done so)

Register
Go to www.masteringbiology.com and click New Students under Register.
· To register using the Student Access Code inside the MasteringBiology Student Access Kit, select Yes, I have an access code. Click Continue.

–OR– Purchase access online: Select No, I need to purchase access online now. Click Continue, and then follow the on-screen instructions to purchase access using a credit card or PayPal. The purchase path includes registration, but the process may differ slightly from the steps printed here.
· License Agreement and Privacy Policy: Click I Accept to indicate that you have read and agree to the license agreement and privacy policy.
· Select the appropriate option under “Do you have a Pearson Education account?” and supply the requested information. If you are taking or have taken Math or Physics classes at TTU that used a Pearson textbook and had on-line assignments, you may already have a Pearson account. If so, you are encouraged to use the same login name and password as before. Upon completion, the Confirmation & Summary page confirms your registration. This information will also be emailed to you for your records. You can either click Log In Now or return to www.masteringbiology.com later.

Log In
Go to www.masteringbiology.com.
Enter your Login Name and Password and click Log In.

Enroll in Your Instructor’s Course and/or Access the Self-Study Area
Upon first login, you’ll be prompted to either:
Enter your instructor’s MasteringBiology Course ID and click Save; OR
Select your text and Go to Study Area

Do the first of these. Under Student ID, you will need to enter your personal TTU R# so that your scores can be recorded and downloaded to the grading spreadsheet.

Congratulations! You have completed registration and have enrolled in your instructor’s MasteringBiology course. To access your course from now on, simply go to www.masteringbiology.com, enter your Login Name and Password, and click Log In. If your instructor has created assignments, you can access them by clicking on the Assignment List button. Otherwise, click on Study Area to access self-study material.

System Requirements & Support
To effectively use the resources on this website, check its system requirements:
Log in to www.masteringbiology.com and click the “System requirements” link at the bottom of the home page. In particular, you may need to check that the latest version of the Flash player is available to your browser.
Customer Support: http://www.masteringbiology.com/support.

Dr. Dini, Dr. McGinley, or Ms. Monje do NOT supply customer service or tech support. If you experience problems with the website, contact the company. You can communicate with customer support via e-mail, chat, or telephone. Try submitting your first assignment well before the deadline because if you have trouble and need to communicate with customer support, their response time may be up to 48 h if via e-mail, or quicker via chat.

Cellular Respiration

Cellular respiration converts chemical energy in glucose to chemical energy in ATP which is the ultimate source of energy used to do "biological work".

Readings From Textbook

Pages 163 - 183
Lecture Video- http://mediacast.ttu.edu/Mediasite/Play/970d298352ea462587ecf88d87bae3421d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b

Powerpoint Presentation

http://www.slideshare.net/MarkMcGinley/cellular-respiration-11758578

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- discus glycolysis, anaerobic respiration, alcohol fermentation, lactic acid fermentation, aerobic respiration, the Kreb's Cycle, and electron transport
- compare and contrast aerobic respiration with anaerobic respiration
- discus why the breakdown of glucose to produce ATP is so much more efficient when oxygen is present
- describe where in the cell the different parts of cellular respiration take place

Why Are Plants Green? or Why Aren't Plants Black

If I was hired as an engineer to design a machine whose job was to convert light energy into chemical energy I probably would not choose to use a green pigment. Instead, I would choose to use a black pigment because black pigments would absorb more energy because they would absorb all wavelengths of light. If you look at a field of plants you will notice that they are green (OK this doesn't work too well around Lubbock in the winter)and we have learned that chlorophyll, a green pigment, is the dominant photosynthetic pigment. What is going on?

Here is one theory about why chlorophyll is the dominant photosynthetic pigment in plants today. Early on there were photosynthetic bacteria with purple pigments (purple is a combination of red and violet). These aquatic bacteria had a very simple sort of cyclic electron flow that was able to convert light energy into energy in ATP (they didn't have non-cyclic flow or the Calvin Cycle).

Origin of chlorophyll- The purple pigment absorbed all wavelengths of light except for the reds and violets. Thus, any bacteria using purple pigments that lived deeper in the water than the purple bacteria on the surface would have no light to use because it had all been absorbed by the surface bacteris (exploitative competition). Because red and violet wavelengths pass through to deeper water, bacteria that contained a pigment that was able to absorb these wavelengths would be able to coexist with the purple bacteria. This was the origin of chlorophyll.

Competition purple and green photosynthetic pigments. Over time there was competition between organisms with purple photosynthetic pigments and green photosynthetic pigments. Obviously, the green photosynthetic pigments won this competition because chlorophyll is the dominant photosynthetic pigment today (there are still examples of photosynthetic bacteria with purple pigments, but they are limited to very harsh environments). Interestingly, chlorophyll came to dominate, not because it was a better at absorbing light energy, but rather because the cyclic flow machinery associated with chlorophyll was more efficient at producing ATP than the machinery associated with the purple pigment was. Thus, it is an evolutionary accident that modern plants are green.

Black Plants

It would be possible for modern plants to be black if they had enough accessory pigments to allow them to absorb all wavelengths of light. In fact, some red algae that live deep below the surface where light levels are low are basically black. Because the amount of light is not the factor that limits the rate of photosynthesis in most terrestrial plants, it is not worth the cost of producing extra accessory pigments. However, deep in the ocean where light levels are low, plants benefit from being able to absorb all wavelengths of light so deep marine algae have invested in extra accessory pigments.

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- discuss why terrestrial plants to not invest in the accessory pigments required to make them black

Factors LImiting the Rate of Photosynthesis

The graph above shows how the rate of photosynthesis is affected by irradiance (light level) and the concentration of carbon dioxide.

The rate of photosynthesis can be limited by a variety of environmental factors including

1) light
2) concentration of carbon dioxide
3) water
4) soil nutrients

Which factor most limits photosynthesis varies between environments.

Light- Can directly limit the rate of photosythesis by limiting the rate at which ATP and NADPH are produced.

Carbon dioxide- can directly limit the rate of photosynthesis by limiting the rate at which the Calvin Cyle takes place.

Water- can indirectly limit the rate of photosynthesis. When plants are water stressed they close their stomata (long before the concentration of water in the cell becomes too low for water to supply electrons to P680). Thus, the rate of photosynthesis is water stressed plants is directly limited by the amount of carbon dioxide in the leaf.

Soil Nutrients- Sometimes the rate limiting step in photosynthesis is the rate at which carbon dioxide + RuBP ==> PGA. This reaction is catalyzed by the enzyme RuBP carboxylase. Increasing the amount of RuBP carboxlyase in the cell can increase the rate at which this reaction occurs. Fertilizing plants with nitrogen will increase the amount of RuBP Carboxylase produced by the plant.

Expected Learning Outcomes

By the end of this class a fully engaged student should be able to

- discuss the factors that can directly or indirectly limit the rates of photosynthesis
- discuss how the most limiting factors should vary between environments
- discuss how the activities of farmers such as irrigation and fertilization can increase photosynthetic rates
- interpret the graph at the top of the post (irradiance measures light intensity and the three lines represent different concentrations of carbon dioxide)
- explain what why the graph shows that shape

Carbon Fixation

Technically, carbon fixation is defined as the first chemical reaction that incorporates carbon dioxide into an organic molecule (a molecule with more than one carbon atom).

In C3 photosynthesis the following step is considered to be carbon fixation-

carbon dioxide + RuBP ==> PGA

In CAM photosynthesis the following is considered to be carbon fixation-

carbon dioxide ===> malate

Note: CAM plants also have the reaction- carbon dioxide + RuBP ===> PGA, but in this case this step is not considered to be carbon fixation.

Sometimes people will loosely use the term carbon fixation to mean the production of glucose by photosynthesis. Be sure that you are aware of how different authors are using the term and you should attempt to use the term as precisely as possible in your own work.

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- define carbon fixation
- identify carbon fixation in C3 and CAM photosynthesis

Stomatal Function and CAM Photosynthesis

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- describe patterns of stomatal opening in C3 plants
- describe CAM photosynthesis
- discuss why CAM photosynthesis is an adaptation in desert enviornments
- discuss why all plants do not use CAM photosynthesis


Lecture Video: http://mediacast.ttu.edu/Mediasite/Play/c952faeba33546d3b8910e6e1bbf716c1d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b



Powerpoint Presentation

http://www.slideshare.net/MarkMcGinley/stomatal-function-and-cam-photosynthesis

Leaf Structure

Lecture Video: http://mediacast.ttu.edu/Mediasite/Play/c952faeba33546d3b8910e6e1bbf716c1d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b




In most plants, leaves are the major sites of photosynthesis. Thus, we can think of leaves as "photosynthesis machines" and use our knowledge of natural selection to try to understand aspects of leaf structure.

Further Reading

http://micro.magnet.fsu.edu/cells/leaftissue/leaftissue.html

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- discuss important differences between animals and plants in gas uptake
- diagram the cross section of a leaf
- discuss the characteristics and purpose of the cuticle, stomata, spongy mesophyl cells, and the palisade cells.
- explain the adaptive basis of leaf structure

Some Suggestions About How to Study About Photosynthesis

Photosynthesis is a complicated and complex process.  I find that many students focus so much on learning about the details that they lose focus on the big picture.

I suggest that you first review the powerpoint presentation I showed in class and then review the relevant material in the book. Next, I would look at the Expected Learning Outcomes in the blog posts on the Light Dependent and Light Independent reactions.  Make sure that you check out the animations. They all use a slightly different approach to cover the same process. You might also try some of the end of the chapter review materials.

 I suggest that you write out answers to all of the expected learning outcomes. Most of these are relatively short. After you have done this you should be able to answer the following three questions.

1) Describe the process of photosynthesis in only one sentence.

2) Describe the process of photosynthesis in only one paragraph.

3) Explain the process of photosynthesis in full detail.

In order to perform well on the test you should be able to explain the material to a fellow classmate.
I think that you can learn a lot by critiquing the answers of your fellow classmates and suggesting how to improve their answers (I find that it is always easier to critique someone else's work than it is to critique my own). Hopefully, the feedback you receive will help you to determine whether you have mastered the material at a deep level or not.

If you would like me to review your written answers to the Expected Learning Outcomes email them to me and I will take a look and get back to you.

More Thoughts on Global Climate Change

As students studying in science-related fields, I think that it is important that you are familiar with, and able to comment intelligently on, the critical scientific debates of the day.

Governor Perry's Comment During a GOP Debate

Here is a link to a video with Governor Perry's answer to a question about climate change at the Republican Presidential Candidates' Debate on September 7, 2011. You can use the knowledge you have gained from BIOL 1403 & 1404 to comment on the Governor's thoughts.

**I am sorry that I couldn't find a clip on youtube that lacked a "comment" in the title of the video- I'll report, you decide ****

http://www.youtube.com/watch?v=eYOQDz9Gt0Q

Tech Professor Receives Hate Mail From Climate Change Deniers

Here is a link to a couple of articles about Tech Political Science Professor Katharine Hayhoe. Dr. Hayhoe is a climate scientist whose research supports the conclusion that human activity have helped to cause global climate change. Dr. Hayhoe is perhaps unique in the debate about climate change because she is an evangelical Christian and she and her husband, a pastor, have written a book about climate change from an evangelical perspective. You can learn more about Dr. Hayhoe and her work by checking out her website.

http://www.katharinehayhoe.com/

I was quite disturbed to learn that her views have led to her receiving hate mail!! If you would like to know more about this then please take a look at the following articles. I think these articles show how misunderstood the process of science is by many Americans!

Texas Tech scientist sees intimidation effort behind barrage of hate mail. http://texasclimatenews.org/wp/?p=4153

Newt Dumps Christian Climate Scientist
http://motherjones.com/environment/2012/01/newt-dumps-leading-climate-scientist


How to Talk to a Climate Skeptic


Here is a link that I just received yesterday from an old BIOL 1404 student.


How to talk to a climate skeptic: responses to the most common skeptical arguments on global warming.
http://grist.org/series/skeptics/#.UvuhszYb1HU.facebook

Cool Underwater Videos

Photo of Juvenile Anenome Fish by Liz Harlin

Hello,

If you need a study break then take the time to watch these two underwater videos.

1. Flores and Alor Islands in Indonesia.  This video is taken by an Australian friend, Josh Jensen.  Josh is an award winning underwater videographer, so enjoy the scenes.  They led a dive trip Indonesia last fall, but because I was teaching, I couldn't go along.

http://www.underseaproductions.com/blog/alor-flores-indonesia-underwater-footage-video

There is a lot of other great footage and photos (taken by Josh's wife Liz Harlin) on the Undersea Productions website.

2. Jellyfish Lake, Palau Micronesia.  This video was shot by Brian Goddard.  I have never met Brian, but through mutual friends I learned about his underwater videos.  He just posted this video on Facebook, so I thought I would share.

Jellyfish Lake is one of the most unusual places that I have ever been.  The lake is located in one of the small Rock Islands of Palau.  The lake is connected to the sea in such a way that water can flow in and out, but organisms can't.  Thus, the jellyfish in the lake have been isolated in this lake for a long period of time.  Because there are no predators in the lake, the jellyfish have lost their ability to sting.  Swimming through the dense clouds of jellyfish and feeling them slide along your body is a pretty creepy feeling.

http://www.youtube.com/watch?v=Ibs6l4fxr5I&feature=share

You can learn more about Jellyfish Lake here

http://www.wondermondo.com/Countries/Au/Palau/RockIslands/JellyfishLake.htm

Photosynthesis 2. Light Independent Reactions

Lecture Video: http://mediacast.ttu.edu/Mediasite/Play/842d916401044c20a370989776ea66631d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


In the light independent reactions the energy stored in ATP and NADPH is converted to energy stored in glucose. This invovles a chemical cycle known as the Calvin Cycle.

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- discuss what links the light dependent and light independent reactions of photosynthesis
- describe the initial step of the Calvin Cycle
- describe the chemical reaction catalyzed by the enzyme RuBP carboxylase
- discuss some interesting characteristics of RuBP carboxylase
- define "carbon fixation" and identify the carbon fixation step in the different modes of photosynthesis
- diagram the Calvin Cycle (at the level of detail that I talked about in class)
- discuss where and why ATP and NADPH are required in the Calvin Cycle
- disucus where in the cell that the Calvin Cycle takes place

Reading From Textbook

pages 198-205

Powerpoint Presentation

Here is a link to the powerpoint presentation that I used in class.

http://www.slideshare.net/MarkMcGinley/light-independent-reactions-of-photosynthesis

Further Viewing

1) This is an excellent animation (narrated by a man with a perfect "announcer's voice"). This animation goes into the amount of detail you are required to know for this class. It even has its own quiz, so see how you do.

http://highered.mcgraw-hill.com/sites/0070960526/student_view0/chapter5/animation_quiz_1.html

2) I didn't know that photosynthesis was such a popular subject for musicians (I can't belive I gave up what would surely have been a lucrative career as a rock star to become a biologist- who knew I could have combined the two). The guy in the video seems like kind of a dufus, but the song is pretty cool, and I learned something from watching it.

http://www.youtube.com/watch?v=OYSD1jOD1dQ

3)Maybe you will find this animation to be helpful

http://www.science.smith.edu/departments/Biology/Bio231/calvin.html

Who Said Valentine's Day and Graphs Don't Mix?

Happy Valentine's Day!

BAC Report- 1st Midterm

Hello Everyone,

The BAC met this afternoon to discuss the comments you had regarding the test questions from the first exam.

Since this morning, I realized that I had incorrectly posted the answers to two questions

a) 35 Blue and 38 Green

 - the answer was listed as b, but the correct answer is d

b) 48 Blue and 50 Green

 - the answer was listed as c, but the correct answer is d

In addition, they brought 5 questions forward to me for consideration.

1) Question 2 Blue and 2 Green

I think that the correct answer for this question is a) selfish trait.  The high density of spines on cactus leaves is a characteristic of that leaf (i.e., a trait).   Because that trait decreases the probability that the leaves are eaten it is a trait that increases the fitness of the cactus.  Therefore, by definition they are "selfish traits".

The BAC argued (vigorously) that answer c) natural selection was an equally good answer.  I disagree with that for one main reason.  According to the definition of natural selection.... natural selection is a "process".  The spines on the leaves of cactus are not a process, therefore this can not be the correct answer.

It is true that the selfish traits were produced by the process of natural selection.  But I think that it is important to distinguish between the process and the trait.

decision- answer a remains the only correct answer.

2) 16 Blue, 21 Green

I think that the correct answer to the question is (c) because male gametes are smaller than female gametes many more male gametes than female gametes are produced.

The BAC argued (very vigorously) that answer e) female reproductive success is resource limited was an equally good answer.  I disagree because the reason that males compete is not determined by the factors that limit female reproductive success but by the fact that there are so many more male gametes than female gametes produced.

decision- answer c remains the only correct answer

3) 42 Blue, 44 Green

I think that the correct answer to this question is d.

An organism acting altruistically towards a non-relative is explained by reciprocal altruism.  In reciprocal altruism, an individual "chooses" to be altruistic because its individual fitness is great when altruistic than when selfish.

Because the organism is helping a non-relative there is no chance for inclusive fitness (inclusive fitness = zero)

thus, because answer a is not true and both answers b and c are true, answer d is the best answer.

decision- d remains the only correct answer.

4) 46 Blue, 47 Green

The two questions related to this description (Blue 45 and 46; Green 46 and 47) were written to be independent questions.

Thus, I intended that the carrying capacity of the populations in question 47 to be unknown.  Without knowing the population sizes of the two species it is impossible to know which species has the highest population growth rate.  Thus, I thought the answer to this question is d.

However, it is easy to see how someone would conclude that N = 10 individuals from question 45 Blue or 46 Green carried on into the following question.  If this is true then there is enough information to answer the question.  Plugging N, rmax and K  for each species into the logisitic growth equation shows that the population growth rate of sparrows is less than the population growth rate of grasshoppers.  Thus, answer b would be the correct answer.

decision- both b and d will be considered to be correct answers to this question.

5) Question 49 Blue, 29 Green

I think that the correct answer to this question is c.  The Singaporean government is trying to encourage women to decide to have more children.

The BAC argued (very vigorously) that answer a) was an equally good answer.

When I used the term "resource-limitation" I meant that the females had so many resources that they were incapable of reproducing (this is the way the term is used in biology).  However, it was clear to me that a student who interpreted "resource limitation" in a different way could have chosen a as an equally good answer.

decision- both a and c will be considered correct answers to this question

The correct answers are now shown in the "First Midterm Answer Keys" post on the blog.

I would like to thank the BAC for spending their time and effort helping to assure that the testing process is as fair as possible.  Make sure you give your BAC reps a little love as well!

First Midterm Answer Keys

Here are the answers that I consider to be correct as of 8:09 AM on Wednesday morning.   It is possible that I have made logic errors when figuring out the answers or transcription errors while adding them to the blog so don't panic if you think there is a mistake. Mistakes will be corrected before the exams are graded by the computer.

BAC Procedure

The BAC will meet this afternoon at 4 PM to discuss any concerns raised by the students.  If you think that one of questions is worded in such a way that a student with a solid understanding of the material you can write out a note telling how an educated student could have come up with a different answer from the one I chose.  You can turn those forms in by placing them on the ledge outside of Dr. Dini's office in the basement.  Please do NOT send comments to BAC by email.  I will not look at these or pass them along to the BAC.  Hard copies only please.  I will pick them up at 3:30 PM.

Final Correct Answers

Form 1, Blue test

1. d
2. a
3. c
4. d
5. b
6. c
7. a
8. a
9. c
10 b
11. c
12. e
13. a
14. d
15. c
16. c
17. d
18. a
19. e
20. d
21. a
22. d
23. b
24. b
25. d
26. b
27. d
28. b
29. e
30. e
31. d
32. a
33. b
34. a
35. d
36. d
37. b
38. b
39. b
40. e
41. c
42. d
43. b
44. e
45. b
46. d and b are both correct answers
47. a
48. d
49. c and a are both correct answers
50. e

Form 2, Green Test

1. d
2. a
3. c
4. a
5. a
6. c
7. b
8. c
9. d
10. b
11. d
12. a
13. e
14. d
15. a
16. c
17. e
18. a
19. d
20. c
21. c
22. d
23. b
24. b
25. d
26. b
27. d
28. b
29. c and a are both correct answers
30. e
31. e
32. e
33. d
34. a
35. b
36. e
37. a
38. d
39. d
40. b
41. b
42. b
43. c
44. d
45. b
46. b
47. d and b are both correct answers
48. e
49. a
50. d

Photosynthesis 1. Light-Dependent Reactions

Lecture Video- http://mediacast.ttu.edu/Mediasite/Play/842d916401044c20a370989776ea66631d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


Photosythesis takes place in two steps. In the first step, known as the light dependent reactions, light energy is converted into chemical energy held in the bonds of ATP and NADPH.

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- list the parts of a photosystem
- discuss the function of a photosystem
- describe where the light dependent reactions of photosythesis occur and discuss why these reactions occur in this location
- describe cyclc electron flow, be able to explain both the energetic result and what chemcical changes occur
- describe non-cyclic electron flow, be able to explain both the energetic result and what chemical changes occur
- describe the cause and the result of chemiosmosis
- answer the question- "why doesn't photosynthesis stop after the production of ATP and NADPH in the light dependent reactions

Readings From Textbook

pages 184 - 197

Further Reading

A simple introduction to the process of photosynthesis
Photosynthesis- http://www.eoearth.org/article/Photosynthesis

Here is a link to some fairly detailed info about photosynthesis (it contains some very good diagrams).
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html

Powerpoint Presentation

Here is the powerpoint presentation that I will use in class.

http://www.slideshare.net/MarkMcGinley/photosynthesis-light-dependent-reactions

Further Viewing

These videos contain animations that might help you to understand what is happening in the light dependent reactions. I encourage you to watch each of these videos.

1) This video has some great animations of what is going on in the light dependent reactions.

http://www.youtube.com/watch?v=hj_WKgnL6MI

2) This is a video of a woman with a very southern accent talking about photosyntheis with some decent animations.

http://www.youtube.com/watch?v=RFl25vSElaE&feature=related

3)Another explanation of light dependent reactions.

http://www.youtube.com/watch?v=BK_cjd6Evcw

Introduction to Energetics

Lecture Video: http://mediacast.ttu.edu/Mediasite/Play/dfea523e65f54ad2af1a25fda81bd2f91d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


In order to understand the two important energetic processes taking place in living organims (photosynthesis and cellular respiration) it is useful to understand some basics of energetics.From a physics perspective, energy is required to do work. Because this is a biology class, we will focus on biological work. The three main types of biological work are (1) active transport, (2) biosynthesis, and (3) movement. The key point for this class is to realize that organisms require energy to do the biological work required to keep them alive.

Energetic processes follow the laws of physics. The two most important laws of physics that relate to energy are the First and Second Laws of Thermodynamics.

First Law of Thermodynamics

The total amount of energy in the universe is constant. Energy can not be created and existing energy can not be destroyed. Energy can only undergo conversion from one form to another.

Biological relevance- No living organisms are capable of creating their own energy so they must get it from another source.

Second Law of Thermodynamics

Left to itself, any system undergoes energy conversion to less organized form. Each time this happens some energy becomes so disorganized that it is no longer available to do work.

Entropy is a measure of the amount of energy that is so disorganized so that it can no longer do work. A simpler way of stating the Second Law of Thermodynamics is that entropy increases over time.

What does it mean when energy becomes disorganized? Another term for "organized energy" is "concentrated energy". Energy is only able to do work when it is concentrated enough to power a particular process.

Apparent Problem

The Second Law of Thermodynamics states that entropy should increase over time, yet life contains highly concentrated energy. How can this be?? They key phrase in the definition is "left to itself". It turns out that energetically, the earth is not left to itself; the earth receives a constant input of energy from the sun and it is this energy that is used to fight entropy.

Light

Light energy from the sun reaches the earth. Light is part of the electromagnetic spectrum. Different portions of the electromagnetic spectrum vary in their wave lengths. Forms of electromagnetic energy with shorter wavelengths (e.g., x rays and gamma rays) contain more energy than forms of energy with longer wave lengths (e.g, radio waves). Interestingly, light falls within the middle of the spectrum with wavelengths from about 400 - 700 nm. Different wavelengths of light have different colors. Ranging from the longest to the shortest wavelengths the colors are red, orange, yellow, blue, green, indigo, violet (some people remember this using ROY G BIV).

As you might recall from your physics class, light has characteristics of waves and of particles. Light energy is "packaged" in units known as photons and the amount of energy in a photon depends of the wavelength of that light.

Fusion reactions on the sun convert nuclear energy in to electromagnetic energy. The electromagnetic energy travels through outer space until reaches the earth. Unfortunately, we,and all other organisms can not directly use light energy to do biological work. Instead light energy must be converted into potential energy stored in the chemical bonds of molecules. This potential (stored) energy can then be used to power biological work.

What Happens When a Photon of Light Hits a Molecule?

Three things can happen when a photon of light hits a molecule- (1) the light can be transmitted (passed through), (2) the light can be reflected, or (3) the photon of light can be absorbed.

When a molecule absorbs a photon of light energy, the electromagnetic energy of light excites an electron in the molecule to a higher energy level (thus, giving the electron potential energy). The excited electron almost immediately falls back to resting stage and the potential energy in the electron is converted into heat (a form of electromagnetic energy) which is released to the atmosphere.

Pigments

When we think of pigments, we think of color. What determines an objects color? The color of an object depends on the wavelengths of light that are reflected back to our eyes. Thus, when you see red you are seeing the red wavelengths that have been reflected from the object that you are looking at. What happens to the other wavelength? They have been absorbed.

Different molecules absorb and reflect different wavelengths of light. A pigment is defined as a molecule that absorbs particular wavelengths of light. What is important to remember is that the color of a pigment is the color of light it reflects.

Absorption Spectrum

An absorption spectrum is a graph that plots how much light energy is absorbed (y-axis, usually measured as intensity or as a percentage) versus the wavelength of the ligh (x-axis, measured in nm). Take a look at the absorption spectrum shown below. You can see that this pigment absorbs mostly green wavelengths and reflects the red and violet wavelengths. When the red and violet wavelengths reach your eye it would appear to you as purple.

Can you draw the absorption spectrum for a red, green and blue pigment?



Lecture Video- http://mediacast.ttu.edu/Mediasite/Play/dfea523e65f54ad2af1a25fda81bd2f91d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


Expected Learning Outcomes

By the end of the course a fully engaged student should be able to

- give examples of biological work
- list different forms of energy, give examples of the different forms, and give examples of energy conversions
- define the First and Second Laws of Thermodynamics and discuss why these laws are important for biologists
- discuss electromagnetic energy, including the wavelengths associated with different forms of electromagnetic energy and the relationship between wavelength and energy
- define a photon
- discuss the three things that can happen when a photon of light hits a molecule
- define a pigment
- draw and interpret an absorption spectrum

Further Reading

Electromagnetic radiation- http://www.eoearth.org/article/Electromagnetic_radiation

Important Information About the First Midterm

The 1st Midterm Exam for BIOL 1404 will be at 6 PM on Tuesday February 12th.

Where you go to take the exam depends on your last name-

A - Q   will take the exam in LH 100
R - Z   will take the exam in Rm 101 in the Biology Building.

Remember
- you may not use your books or notes
- the test will consist of 50 multiple choice questions (we will provide the scantron)
     - please try very hard to fill out the scantron correctly!!!!!
- there is no retest for this midterm
- there will be no BAC forms attached to the exam.  Instead
  a) I will post what I think are the correct answers on the bulletin board outside LH 100 prior to to class on WEDNESDAY morning
  b) you can turn in any concerns you have about test questions prior to 3:30 on Wednesday afternoon
  c) the BAC will meet to discuss the exam at 4PM on Wednesday

Cool Ecology Video From Kruger Park in South Africa

A past BIOL 1404 student sent me a link to this video. It seems like almost everything that we have talked about so far in BIOL 1404 is going on in this video. The highlight of my biology life was visiting Kruger Park when I was about 13 (how sad to peak so young). I saw lots of amazing animals, but I didn't see anything like this. This video keeps getting better so watch it all the way to the end. Enjoy!!

http://www.youtube.com/watch?v=LU8DDYz68kM

Global Carbon Cycle and Climate Change

Human activity, including burning fossil fuels, deforestation, and burning trees, has altered the global carbon cycle. This alternation of the global carbon cycle is the proposed cause of global climate change (global warming).

Obviously, global climate change is a very imporant issue facing us today. If you are alive and paying any attention, then you probably know that there is some disgreement out there about (1) whether global warming is occuring, (2) if it is occuring is it a natural occurence or is it caused by humans, and (3)what should we as individuals and a society do about these issues. As I mentioned in class, it is very important that you understand what components of the debate are facts and what components of the debate are based on mathematical models or other forms of argument. I think that it is important that you should be able to explain to other people why scientists will never be able to conduct the experiment that will nail down whether or not humans are causing global warming (we have only one earth).

I think that it is important for you to have access to good information. Here are some links to what I consider to be some of the best and most reliable sources of information about this topic. Although some of these articles go into much more detail than are required for this class you should know where to find reliable information about this topic.

Further Reading

Carbon cycle- http://www.eoearth.org/article/Carbon_cycle

Global warming- http://www.eoearth.org/article/Global_warming

Global warming Frequenty Asked Questions- http://www.eoearth.org/article/Global_warming_frequently_asked_questions

Climate change FAQ- http://www.eoearth.org/article/Climate_change_FAQs

Intergovenmental Panel on Climate Change- http://www.eoearth.org/article/Intergovernmental_Panel_on_Climate_Change_%28IPCC%29

IPCC Assessment for Policymakers- http://www.eoearth.org/article/IPCC_Fourth_Assessment_Report%2C_Working_Group_I%3A_Summary_for_Policymakers

If you would like additional information about global climate change then you can take a look at a presentation I developed for another class.

Global Carbon Cycle and Global Climate Change
http://www.slideshare.net/secret/C6iDTujQlIh73C

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- diagram the global carbon cycle
- discuss how humans have altered the global carbon cycle
- discuss how the atmospheric concentration of carbon dioxide varies annually
- discuss the proposed relationship between human caused changes in the global carbon cycle and global warming
- discuss alternative causes of global warming
- discuss the experiment that would be required to determine whether or not human activity is the cause of global warming
- articulate and defend their own personal view of how they intend to deal with the global warming issue

Ecosystem Ecology

NOTE:  This material WILL be included on the First Midterm


Ecosystem ecologists focus on the flow of energy and the cycling of nutrients through the ecosystem.

Further Readings

Ecosystems- http://www.eoearth.org/article/Ecosystem

Ecological energetics- http://www.eoearth.org/article/Ecological_energetics

Nitrogen cycle- http://www.eoearth.org/article/Nitrogen_cycle

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- diagram and discuss the flow of energy through an ecosystem
- diagram, discuss the causes of, and discuss some of the implications of the enegy pyramid
- diagram nitrogen cycle within an ecosystem
- discuss the factors that influence the rate of flow from dead bodies to the soil and discuss the implications of differences in this rate

Community Ecology- The Portal Experiment

Lecture Video- http://mediacast.ttu.edu/Mediasite/Play/7feddd71db3e46eaa48d3bd62f4b50e71d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


Here are some photos from the research site in Portal, Arizona. For more information about the research project at Portal you can look at their website at
http://portal.weecology.org/

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- distinguish between direct and indirect, positive and negative effects
- describe the experimental design that Dr. Brown and his colleagues used to study exploitative competition between desert rats and rodents
- discuss the "search the the missing indirect positive effect of rodents on ants" and how that dilema was solved
-discuss why and how the outcome of studies of interactions between organisms can vary over time
- discuss the way that the ecological community responded when they learned the importance of long term studies
- discuss how indirect interactions lead to one of my favorite phrases "the world is complicated"

Community Ecology

Required Readings

Community Ecology- http://www.eoearth.org/article/Community_ecology

Competition- http://www.eoearth.org/article/Competition

Interspecific Competition- http://www.eoearth.org/article/Interspecific_competition

Exploitative Competition- http://www.eoearth.org/article/Exploitative_competition

Predation- http://www.eoearth.org/article/Predation

Mutualism- http://www.eoearth.org/article/Mutualism

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- define competition, exploitative competition and interference competition

- identify and explain examples of exploitative and interference competition from a variety of environments

- define predation (narrow and broad sense), herbivory, and parasitms

- identify and explain examples of predation, herbivory, and parasitism from a variety of environments

- identify examples of morphological and behavioral adaptations that animals have to help capture their food

- identify examples of morphological, biochemical, or behavioral adaptations that animals have to protect them from predators

- identify and explain examples of mutualisms from a variety of habitats


Past Test Questions (answers at bottom of post)

In the southeastern United States, a weedy plant called Kudzu has caused a great deal of problems. Because Kudzu has such high growth rates it is able to rapidly overgrow buildings and other plants.

1. Which of the following would best describe the ecological relationship between Kudzu and a species of pine tree that is commonly overgrown by Kudzu?
(a) mutualism
(b) parasitism
(c) exploitative competition
(d) herbivory
(e) none of the above

Answer- 1. c

Human Population Growth

Lecture Video: http://mediacast.ttu.edu/Mediasite/Play/52d8d4c10b014322accd92829c7c5c991d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


I have spent a lot of time trying to convince you that exponential growth is an unrealistic model of population growth. Interestingly, human populations have experienced exponential-like growth. How can this be?

What makes humans different from other species?

In other species per capita birth rates and per capita deaths rates are density dependent. However, as human populations have increased there has been no corresponding decline in per capita birth rates or increase in per capita death rates. What makes humans different from other species?

Humans have the ability to alter their environment so that they can avoid the density dependent effects on birth and death rates. 1) Humans have increased food production by improvements in agriculture (e.g., irrigation, fertilization, mechanized farming, genetically improved crops). 2) Humans have been able to decrease death rates by improvements in medicine and public health (things as simple as not pooping in the water you drink helps a lot!). 3) Humans have elimnated most human predators (ocassionally, someone gets killed by a shark or a mountain lion).

Where is human population growth occuring?

The rates of human population growth are not the same in all regions. Today, human populations are increasing in size much faster in developing countries (e.g., Mexico, other countries in Central America, Africa, and Southeast Asia) than they are in developed countries (e.g, USA, Canda, Western Europe). The figure at the top of this post shows the patterns of population growth in developed and developing nations.

Thus we see that populations are increasing most rapidly in the countries that are least able to deal with a rapidly increasing population. See "Population Challenges-The Basics" that can be downloaded from the Population Institute's website.
http://www.populationinstitute.org/population-issues/index.php

Human Population Growth Problem?

There is a great deal of debate about whether increasing human populations are a problem or not, and if they are what should be done about it. Unfortunately, we don't have time to discuss this issue in very much detail in class. My personal opinion is that we have too many people consuming too many resources and the last thing that we need are billions more people living on the planet. This is an issue that I am always intersted in talking more about if you would like to chat.

Further Reading

The section on Human Population Growth in your textbook is quite good.

Also see the article "Human Population Explosion" from the EoE.
http://www.eoearth.org/article/Human_population_explosion

Both of these contain a good discussion of the "demographic transition".

Really Cool Video

Here is a link to a YouTube video on "World Population" The first minute and a half or so is a little boring, so you can skip over it if you wish. However, I think the animation showing when and where human population growth has been occuring is really cool.

http://www.youtube.com/watch?v=4BbkQiQyaYc

Powerpoint Presentation

http://www.slideshare.net/MarkMcGinley/human-population-growth-16369173

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- describe patterns of human population growth in developed and developing nations

- discuss some reasons why the pattern of population growth in humans is so different from that in other species

- describe the demographic transition

- discuss their own personal view of human population growth.

Past Test Questions (answers at bottom of post)

1. In developing countries, why have per capita birth rates not decreased as human populations have increased in size?
(a) because we have increased rates of food production
(b) because of the improvements in education of women
(c) because of improvements in medical care
(d) a and c
(e) a, b, and c

2. Why do some people consider the high growth rates of human populations in developing countries to be of concern?
(a) because many people are born into conditions that do not provide them enough food
(b) because many people are born into conditions without clean water and adequate sanitation
(c) because increasing population sizes have led to increasing habitat destruction
(d) a, b, and c
(e) none of the above

answers- 1.d, 2.d

Marathon SI Review

In addition to their regularly scheduled SI session, Suzanne and Jeffrey will hold two review sessions this week.

Suzanne: Thursday at 3:30 in Chem 49
Jeffrey: Sunday at 1 - 4  in Biol LH 100

My Group OH scheduled for 6:30 on Monday Feb 12th can be considered as my Marathon Review.  Hope to see you there.

Population Growth- Final Thoughts

We have discussed how population ecologists have tried to develop a model (the logistic growth model) that helps them to understand the factors that affect population growth.

We talked a lot about the graph plotting how the population size would vary over time in a population that started much smaller than the carrying capacity (the s-curve). Why does logistic growth show this pattern?

Initially, the population is growing slowly. When populations are small the per capita growth rate is large but because there are only a few individuals in the population rN is small. Over time, the population growth rate increases becasue populations are still small enough that r is still relatively large and now a larger N allows rN to be a bigger number. Population growth rate starts to slow as populations reach their carrying capacity because in large populations the per capitat growth rate is small and even though N is large rN is small. When the population reaches its carrying capacity b = d, so population growth stops.

Density Dependent Population Regulation

We notice that populations don't keep increasing in size forever. That is because populations are naturally self regulating. As population size increases the per capita birth rate declines for the biological reasons that we discused earlier. (When a parameter decreases as population size increases that parameter is said to be negatively density dependent. As population size increases the per capitat death rates increase for the biological reasons that we discussed earlier. (when a parameter increases as the population size increases that parameter is said to be positively density dependent). Thus, the per capita birth and death rates are naturally density dependent in such a way that eventually causes the population size of species to stop growing.

Past Test Questions (answers at bottom of post)

1. In logistic growth, what is the per capita growth rate when N = 1/2K?
(a) rmax
(b) 2(rmax)
(c) ½ (rmax)
(d) it is a maximum
(e) you can not answer this questions with the information provided.

2. How can you calculate the population growth rate?
(a) subtract B from D
(b) add the per capita death rate to the per capita birth rate
(c) multiply r by N
(d) divide dN/dt by N
(e) a and c

3. Why don’t we expect raccoons to show exponential growth?
(a) per capita birth rates increase as population sizes increase
(b) per capita death rates increase as population sizes increase
(c) per capita birth rates decrease as population sizes increase
(d) b and c
(e) none of the above

4. Which of the following are true when populations are at their carrying capacity?
(a) dN/dt > 0
(b) r < 0
(c) b = d
(d) B > D
(e) a and d


answers- 1.e, 2.c, 3.d, 4.c

Fun With Graphs- Quiz Yourself

Here are some questions that I have designed to let you know if you are understanding the graphs well enough to meet the course expected learning outcomes. I suggest that you do not try to answer these questions until you have thoroughly reviewed all of the information about the population ecology graphs. (I will put the answers for the multiple choice questions at the bottom of this post, for the others you need to find out whether your answers are correct or not).

1. What are the correct axes for a graph showing how population growth rate depends on population size in logistic growth?

a) x- N y- t
b) x- N y- dN/dt
c) x- dN/dt y- N
d) x- dN/dt y- t
e) x- N y- r

2. Which of the following best describes the graph that shows how the per capita growth rate varies over time in exponential growth?

a) the per capita growth rate decreases over time
b) the per capita growth rate increases over time
c) the per capita growth rate does not change over time
d) the per capita growth rate increases until it reaches a maximum and then decreases to zero when the population reaches the carrying capacity
e) the per capita death rate is initially very negative and gets less negative over time.

3. What would I ask to make you draw this graph?
a) show how the population size varies over time in logistic growth when the initial population size is much smaller than the carrying capacity
b) show how the population growth rate depends on the population size in logistic growth when the intitial population is much smaller than the carrying capacity
c) show how the population size depends on population size in logistic growth when the initial population size is much smaller than the carryuing capacity
d) show how the population size varies over time in logistic growth when the intitial population is much larger than the carrying capacity

4. What are the axes of a graph showing how the per capita growth rate depends on the population size in logistic growth?

a) x- logistic y- exponential
b) x- logistic y- r
c) x-N y-r
d) x-r y-N
e) x-N y-dN/dt

5. Which of the following is true when populations are at their carrying capacity?

a) N = 100 individuals
b) dN/dt = 0
c) b > d
d) b = d
e) b and d

6. Describe how the population growth rate varies over time in logistic growth when the intial population size is much larger than the carrying capacity.

7. Draw the graph that shows how the population size varies over time in logistic growth when the initial population size is much smaller than the carrying capacity.

Answers. 1.b, 2.c, 3.b, 4.c, 5.e

Population Biology 3. Logistic Growth

Lecture Video- http://mediacast.ttu.edu/Mediasite/Play/83f60ff04a32459896329229dc3cc5fd1d?catalog=4dc7289a-d3e0-4ae5-8fdc-5b86c027a06b


We are trying to develop a mathematical model that helps us to understand patterns of population growth. So far our first attempt, the exponential growth model, did not help us to understand population growth (for reasons that I hope that you understand by now).

The "Real" world

In our attemtp to think about population growth in the real world, we attempted to examine how per capitat birth rates and per capitat death rates should vary as population size varies. The model that describes this pattern of growth is known as the logistic growth model. It is important to realize that although this model is much more realistic, and therefore useful to us, than the exponential growth model, the logistic growth model still only exmaines what I call "the theoretical real world". That is, this model applies to our ideas about how populations should generally behave and do not thus relate directly to studying the population sizes of white tailed deer in central Texas or parrot fish on a coral reef in Fiji. These real world situations are much harder to understand than the simple "idealized" populations that I am talking about in BIOL 1404. You can take an Advanced Population Biology course if you want to learn more about how to apply these models to the "real real world".

Logistic Growth

We have discussed why, in the real world, r should decrease as population sizes increase. If this is the case then there is a population size at which the per capita birth rate equals the per capita death rate. We call this population size the carrying capacity.

1) When populations are smaller than the carrying capacity we expect them to increase in size until they reach the carrying capacity.

2) When populations are larger than carrying capacity we espect them to decrease in size untile they reach the carrying capacity.

3) When the population size equals the carrying capacity we expect no change in the size of the population.

The logistic growth equation is a mathematical equation developed by biologists to describe patterns of population growth consistent with the ideas above. Before focusing on the biological isights that we can gain from the logistic growth model (the real purpose of everything we have been doing) it is important to really understand patterns of logistic growth. Hopefully, this powerpoint presentation will help you understand these patterns better.

Powerpoint Presentation

Click here for a powerpoint presentation entitled "Fun With Graphs- Logistic Growth"

http://www.slideshare.net/secret/gyB3cjnSplLw41

NOTE: THERE IS AN ERROR ON SLIDE 16 OF THIS PRESENTATION!!!

The title of the graph on slide 16 should read "Logistic Growth: dN/dt vs t (Not N), N initially << k"

The x-axis of the graph is TIME (please ignore the values of K on the x-axis because K does not belong on the time axis). The shape of the graph is correct. Make sure you change the x-axis to Time rather than Population Size.

Expected Learning Outcomes

By the end of this course a fully engaged students should be able to

- define the carrying capacity

- draw, and interpret the following graphs associated with logistic growth
-how population size changes over time in logistic growth when the initial population size is much smaller than the carrying capacity
-how the population size changes over time in logistic growth when the initial population size is much larger than the carrying capacity
-how population growth rate changes over time in logistic growth when the initial population size is much smaller than the carrying capacity
-how the population growth rate changes over time in logistic growth when the initial population size is much larger than the carrying capacity
-how the per capita growth rate varies over time in logistic growth
-how the population growth rate varies over time in logistic growth

- discuss the causes for the shape of the s-curve (this answer will need to include a discussion of both math and biology)

- discuss the factors that regulate population size, be able to distinguish between density dependent and density independent factors that regulate population growth and give examples