Using Natural Selection to Understand Adaptations

We can use the process of natural selection to help us understand variation in phenotypes of different organisms living in different environments.

Reading

Optimal Foraging Theory - http://en.wikipedia.org/wiki/Optimal_foraging_theory

Expected Learning Outcomes

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

1) discuss the importance of trade-offs
2) discuss why scientists use mathematical models to formulate arguments
3) briefly discuss the process of developing and optimality model
4) discuss the type of organisms whose foraging could be understood using the diet breadth model
5) derive the equation for the profitability of the generalist and specialist diet in the diet breadth model
6) discuss the predictions of the diet breadth model and discuss experiments designed to test these predictions.

Natural Selection

An understanding of the process of natural selection helps us to understand the amazing diversity of life on the earth.

Expected Learning Outcomes

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

1) define the process of natural selection

2) distinguish between the patterns of stabilizing, disruptive, and directional selection and provide examples of each pattern

3) describe how the process of natural selection has produced a trait that is an adaptation to a particular environmental condition.

4) explain why organisms are not expected to be perfectly adapted to their environments

5) discuss the conditions that would cause natural selection to stop

6) explain why natural selection is expected to produce selfish traits

Readings

Natural selection http://www.eoearth.org/article/Natural_selection


Here is a link to a website from UC Berkeley-

http://evolution.berkeley.edu/evolibrary/article/evo_25

Here is a copy of the "famous" frequency distribution of heights that I was looking for.  Thanks Alex!!

The Hierarchical Nature of Ecology

In order to understand the science behind environmental issues it will be necessary to have a basic knowledge of the science of ecology.

Ecology has been defined in many ways. The definition that I prefer is that "ecology is the scientific study of the interactions between organism and their environment." Organisms interact with two distincly different parts of the environment. The "abiotic (non-living) environment" includes all of the non-living attributes of the environment including water, soil characteristics, temperature, etc. The "biotic environment" includes all of the living organisms and involves interactions such as competition, predation, mutualism, etc.

Hierarchical Organization of Ecology

Ecology can be studied at different hierarchical levels.

1. Individuals have phenotypic characteristics such as morphology (e.g., eye color, height, etc.), physiology (blood type, photosynthetic ability, etc.), and behavior (food preferences, response to stimuli, etc.). We can understand the characteristics of organisms by studying how natural selection has affected those traits.

2. A population is a group of individuals of the same species that live in the same area. Individuals in the same population interact via competition and sometimes predation (e.g., canibalism).

Some species live in very large populations whereas others live in very small populations. Ecologists are interested in understanding the factors that influence population size (this is important because when population size equals zero individuals then a population has gone extinct.)

3. A community is a group of different species living together in the same environment. Interspecific interactions including competition, predation, and mutualisms are some of the most interesting, and most important, aspects of ecology.

4. An ecosystem involves all of the biotic components in a community as well as the abiotic components. Unlike the lower levels of the ecological hierarchy where the focus is on living organisms, ecosystem ecologists are interested in understanding theh flow of energy and nutrients through the ecosystem. Some of the most important environmental issues facing us today are caused by human alteration of these cycles.

Expected Learning Outcomes

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

- define ecology

- define individual, population, community, and ecosystem

- diagram and discuss the hierarchical organization of ecology

- discuss examples of how one level of ecology can bge affected by the level above or below it

Reading

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

Organization of Life: Species, Populations, Communities, and Ecosystems in PhysicalGeography.net by Michael Pidwirny
http://www.physicalgeography.net/fundamentals/9d.html