A Few Cool Community Ecology Videos

Here are a couple of cool videos.

Watch to see what happens to this crab!!

http://thedailywh.at/2015/02/battle-day-hungry-octopus-kidnaps-crab-eats-lunch/

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

This Video was just posted today on Facebook by an ex-1404 student.  Birds are smart.  Pretty cool.

www.youtube.com/watch?v=OaYlbsy6wLw

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


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

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".

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

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

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

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.