Chapter 04 - Evolutionary Ecology

What was Charles Darwin's Theory of Natural Selection?

Individuals are naturally selected to drive the evolution of their population

What were Gregor Mendel's experiments, what discovery did it lead to?

He studied garden peas (Pisum sativum) and cross bred them with each other, this lead to the discovery of Genes and Alleles

What are Genes?

Sections of DNA that encode for a trait

What is an Allele?

Alternative forms of genes (Ex. Curly hair or Straight hair) that can be Dominant or Recessive

What is Phenotypic Variation and what causes it?

It is the differences of traits among Individuals, this is caused by genes combined with the interactions with the environment.

What would be examples of Phenotypic Variation?

Phenotypic Plasticity and Ecotypes

What is Phenotypic Plasticity?

Individuals of the same genotype are able to express different phenotypes due to their environment.

What are Ecotypes?

Populations that have genetically developed to withstand their environment.

The movement of Alpine Fish had caused them to become geographically isolated with the rest of their populations, this isolated population was seen to have a high level of DNA differentiation from the original population. This was an example for what ecological term?

Phenotypic Variation

What is Hardy Weinberg and why is it a 'null' model?

Principle used to help identify gene frequencies within a population, known to be a null model because it assumes that there are no evolutionary forces present

What conditions are necessary for Hardy Weinberg?

1. Random Mating

2. No Mutations

3. Large Population Size

4. No Immigration

5. Equal fitness for all Genotypes

What is the Hardy Weinberg equation?

p^2 + 2pq + q^2

Is Hardy-Weinberg realistic?

No, it is theoretical

What is Genetic Drift and what does it do to Genetic Diversity?

Change in allele frequencies due to change or random events, this reduces the genetic diversity in a population over time

Why does Genetic Drift lower Genetic Diversity?

It can either increase existing alleles or completely eliminate them.

What are the two different ways for Genetic Drift to occur?

Founder Effect and Bottlenecks

What is the Founder Effect?

Individuals in a population move away and form a new population that is different from the original population

What are Bottlenecks?

A catastrophic event that results in the death of many individuals within a population (ex. Volcano or Tornado)

What is Natural Selection?

Individuals in a population with higher fitness are able to survive and reproduce, this allows for their genes to be selected and added to the population gene pool

What is the Fitness of an individual?

One's ability to reproduce offspring and pass off their genes to the next generation

What were the three types of Natural Selection Models discussed?

Stabilizing Selection, Directional Selection, and Disruptive Selection

Stabilizing Selection

Selection that impedes changes in population by favoring "intermediate phenotypes"

Directional Selection

Selection that leads to changes in populations by favoring a specific extreme phenotype

Disruptive Selection

Selection that creates a bimodal distribution by favoring both sides of the extreme phenotypes

Darwin's Finches exhibited Disruptive Selection, why might this be the case?

Their environment had seeds that were either too big to eat or too small which resulted in both extreme phenotypes to be more favored

What is Heritability?

The proportion of variation among individuals that we can attribute to genes (NOT CAUSED BY PHENOTYPIC PLASTICITY)

What is the equation to quantify Heritability?

h^2 = Vg / Vp (Vg + Ve)

What kind of populations will be greatly affected by Genetic Drift?

Smaller populations due their smaller gene pool

When comparing Mainland to Islands, which will be greatly affected by Genetic Drift and why?

Islands due to their smaller population which result in a smaller gene pool.

How does Inbreeding result in extinction? Where is Inbreeding more prone to occur?

Inbreeding results in offspring that are prone to dying young and unable to reproduce, populations with a small gene pool are more prone to Inbreeding.

Artificial Selection

Selective breeding

GMOs

Deletion and addition of genes

The use of Chemicals in Agriculture has what unintended consequence?

Chemical resistance among pests.