Environmental Science Ch. 5 Study Guide

Define Evolution

Change in population gene pool over time.

What is a gene pool and what does it have to do with evolution?

All the genes present in a population. Evolution focuses on the change in the gene pool in a population.

What are the four mechanisms of evolution?

Mutation, Migration, Genetic Drift, & Natural Selection

What is natural selection?

Traits that improve an organism’s chances of survival and reproduction are passed on more frequently.

What are the three conditions of natural selection?

Organisms produce more offspring than can survive; Individuals of a species vary in their characteristics; Individuals vary in their fitness.

What does an organism’s fitness describe?

How reproductively successful an organism is in its environment.

What are two ways humans use artificial selection?

Dog Breeders & Agriculture

What is allopatric speciation?

Speciation caused by geographic separation of populations.

What percent of species do scientists estimate are extinct?

99%

What is a mass extinction?

Huge numbers of species gradually go extinct one at a time

What is the Holocene?

6th Mass Extinction, human driven

What is the difference between a fundamental and realized niche?

Fundamental niche: full niche of a species

Realized niche: a niche restricted by competition

What is an organism’s tolerance?

Ability to survive and reproduce under changing environmental conditions.

What are the benefits and disadvantages of being a specialist?

They are very good at the thing they do, but they may not be as successful as specialists in a given situation.

What are the benefits and disadvantages of being a generalist?

They are able to live in many different places and weather conditions, but they may not be as successful as specialists in a given situation.

What is the difference between intraspecific and interspecific competition?

Intraspecific: competition among members of the same species

Interspecific: competition among members of two or more different species.

What does competitive exclusion mean?

When two or more species try to occupy the exact same niche — one wins, one loses

What is resource partitioning?

Division of resources by specializing in different ways when species complete for common resources.

What is predation? What does coevolution have to do with predation?

The process by which an individual of one species, a predator, hunts, captures, kills, and consumes an individual of another species, the prey. Coevolution is the response to this because with every predator & prey relationship, the prey will adapt new changes to combat the predator, and the predator will adapt to the prey’s adaptation with their own new changes.

What is herbivory?

The interaction in which an animal feeds on a plant animals that feed on them (toxic or distasteful chemicals, thorns, etc.)

What is parasitism?

Relationshop in which one organism, the parasite, depends on another, the host, for nourishment or some other benefit: the host is harmed.

What is the difference between commensalism and mutualism?

Mutualism: a relationship in which two or more species benefit.

Commensalism: a relationship in which one species benefits and the other is unaffected.

Classify the following relationships:

a. A bee pollinating flowers.

b. Birds eating the insects that grazing animals kick up.

c. A leech attaching to the bottom of your food.

a. Mutualism

b. Commensalism

c. Parasitism

What are the two processes autotrophs use to introduce usable energy into an ecosystem?

Photosynthesis & Chemosynthesis

What is the difference between a primary and secondary consumer?

Primary consumers eat producers. Secondary consumers eat primary consumers.

What do detritivores and decomposers eat?

Nonliving organic matter

What is a scavenger?

Large detritivores, such as vultures.

Describe the ten percent rule.

Each trophic level contains just 10% of the energy of the trophic level below it.

What does biomass describe?

The total amount of living tissue each trophic level contains

What is a keystone species?

A species that has a strong or wide reaching impact on a community.

What is an invasive species?

Organisms introduced into an area where they are not naturally found.

What is the difference between primary and secondary succession?

Primary: when changes in a species composition in an area over time happens in a place with no life and no soil.

Secondary: when changes in a species composition in area over time happens in a place where a natural disaster happened.