AP Environmental Science Module Three Lesson Four Overview

Diversity and Change Within Ecosystems

image of an island with text that reads Diversity and Change Within Ecosystems

In lesson 4 we will look at how organisms and ecosystems change over time.

Objectives and Checklist

By the end of this lesson, you will be able to:

Define and explain climate shifts, species movement and ecological succession.
Explain the importance of biodiversity and how natural selection/evolution works to increase ecosystem diversity.
Describe and give an example of each of the 4 ecosystem services.

Key Terms

primary succession: Succession (ecological change) that occurs on land that does not have suitable soil
secondary succession: Succession (ecological change) that occurs on land that has already been established
pioneer species: species with the ability to colonize new areas rapidly
mid successional plant: Plants that are semi-tolerant of shade, usually fast-growing and longer-lived
early successional plants: Sun-loving, fast-growing pioneer plants are short-lived
late successional plants: Shade tolerant plants, hardwoods
limiting factors: Factor that limits the growth, abundance, or distribution of the population of a species in an ecosystem
climax community: Fairly stable, self-sustaining community in an advanced stage of ecological succession
convergent evolution: process by which unrelated species become more similar as they adapt to the same kind of environment
divergent evolution: Process by which the same species becomes more different as they adapt to different types of environments
stabilizing natural selection: a type of natural selection in which the average form of a trait (heterozygous) is favored
directional natural selection: Occurs when natural selection favors one allele; occurs in the direction of the homozygous trait
disruptive natural selection: Occurs when natural selection favors the 2 homozygous (or extreme) traits and does not favor the heterozygous or average trait
adaptation: Any heritable trait that enables an organism to survive through natural selections and reproduce better under prevailing environmental conditions
gene pool: all of the alleles in a population
natural selection: The process by which traits that enhance survival and reproduction are passed on more frequently to future generations than those that do not, thus altering the genetic makeup of populations through time
selective breeding: Occurs when natural selection favors the two extremes (homozygous) and not the average (heterozygous)
speciation: formation of a new species
genetic drift: Changes in the gene pool due to having a small population
adaptive radiation: process by which a single species or small group of species evolves into several different forms that live in different ways
biodiversity: variety of life in an ecosystem
species diversity: number of different kinds of organisms within a community
genetic diversity: variety of different genes within a species
ecological diversity: Variety of ecosystems and ecological communities
ecological tolerance: This describes the range of conditions that an organism can tolerate and survive. Some of these conditions include: temperature, level of salinity, and amount of sunlight available

AP Environmental Science Module Three Lesson Four Overview

Objectives and Checklist

Key Terms

Reference List

Resources

Image Citations

Video Citations