Unit TEN Ecology
TOPIC 1 - Populations
Human Population Growth over time:
1. Compare and contrast exponential growth with logistic growth in populations.
a. When does each occur, how do they start, what feature does logistic growth exhibit?
b. What factors might cause the carrying capacity for an organism to change?
2. Describe how predator/prey relationships affect a population size.
a. Are predators affected by their prey population size, vice versa, or both?
b. What can happen to a population in the absence of a predator?
3. Describe the human population growth. Calculate the annual growth rate using data for a population and calculate the doubling time with the given formula. (see deer packet)
4. Give examples of density-dependent factors and density-independent factors that affect a population.
Topic 2 - Nitrogen Cycle
Watch this video on how excess nitrogen leads to dead zones! https://www.youtube.com/watch?v=htggO_QOIEc
EUTROPHICATION VIDEO:
https://www.youtube.com/watch?v=XEZpo9uLIc0
Crash Course: https://www.youtube.com/watch?v=leHy-Y_8nRs
NASA monitoring phytoplankton: https://www.youtube.com/watch?v=XEZpo9uLIc0
Video shown in class about the Great Barrier Reef and Nitrogen
Hypothesis:
https://www.youtube.com/watch?v=kGRyNWrkG_w
Why this really matters? EUTROPHICATION - when nutrient cycles are thrown off balance by human activity http://coseenow.net/files/2008/11/eutrophication.swf
Use this website to complete the Eutrophication cartoon. You should write captions in your own words - not copy the phrases from this animation. You must use all 4 boxes in your cartoon and the captions/pictures should match the title of each box!
This is sundew - a carnivorous plant
This photo was taken in a bog up in SE Alaska - the bog does not drail well and the ground is real squishy. The soil is poor in nitrogen which is why these plants have evolved to obtain nitrogen from eating insects. The plant secretes enzymes that digest the insect and then absorbs the building blocks.
Did you hear that poachers were taking venus fly trap plants from a park in North Carolina and have been charged with a felony because this wild population is endangered? Just say "no" to poachers. Interesting blog post.
TOPIC 3 - ENERGY TRANSFERS IN FOOD CHAINS/WEBS
In this topic you will look at why the base of all food chains needs to be larger than each level above it. For example, you will learn that an ecosystem is limited by the primary productivity of the producers --they will determine how many other organisms the ecosystem can support. The general rule is that each trophic level only passes on about 10% of its total chemical energy to the next level. For example, 1st level consumers only get about 10% of the available energy of the producers in an ecosystem. This is because some need to remain alive, growing and reproducing in order to sustain the population for the future. Additionally, as each organism lives, grows and reproduces, it used up energy along the way. Some of that energy is used to do work by the organism and much of it is then lost to the environment as heat. So a population of apex predators should always be the smallest population in an ecosystem.
How does this relate to our world today? Consider how we plan to feed the growing human population!
Watch this video about our current state of the oceans: