AP Environmental Science: Modules 8-14 Review

biodiversity

the variety of life in a particular habitat or ecosystem, including the number of species, genetic diversity, and ecosystem diversity.

Genetic Diversity

The measure of the genetic variation among individuals in a population.

Population Bottleneck

A drastic reduction in the amount of genetic diversity carried by surviving individuals that occurs when a large population declines sharply in number.

Species Diversity

A measure that indicates the number of species in a region or in a particular ecosystem.

Habitat Diversity

The variety of habitats that exist in a given ecosystem.

Specialists

Species that can only live under a narrow range of biotic or abiotic conditions.

Generalists

Species that can live under a wide range of biotic and abiotic conditions.

Ecosystem Diversity

The variety of ecosystems that exist in a given region.

Species Richness

The number of different species in a given area of an ecosystem, such as a pond, the canopy of a tree, or a plot of grassland.

Species Evenness

The relative proportion of individuals within the different species in a given area, indicating whether an ecosystem is dominated by one species or if all species have similar abundances.

Ecosystem Service

The process by which life-supporting resources such as clean water, timber, fisheries, and agricultural crops are produced.

Provisions

Goods produced by ecosystems that humans can use directly, such as lumber, food, crops, medicinal plants, natural rubber, and furs.

Regulating Services

Processes by which natural ecosystems help to regulate environmental conditions, such as tropical rainforests and oceans removing carbon from the atmosphere.

Support Systems

Natural ecosystem services that would be extremely costly for humans to generate, such as crop pollination, natural pest control, and water filtration.

Cultural Services

Cultural and aesthetic benefits provided by ecosystems that have instrumental value because people are willing to pay for them (e.g., National Parks).

Aquaculture

The farming of fish, shellfish, and seaweed.

Island Biogeography

The study of how species are distributed and interacting on islands.

Species Area Curve

A description of how the number of species on an island increases with the area of the island.

What factors determine the number of species on islands?

• Rates of colonization

• Rates of extinction

• Area of an island

Distance from the island to a mainland source of species

Why are certain species on islands particularly vulnerable to invasive species?

Many species that are native to islands have evolved into specialists that can have a narrow diet and have not developed defenses against predators or pathogens. When invasive species are introduced, most being generalists, they outcompete native species or consume the native species who do not have developed defenses against the invasive predator, declining the native species numbers.

Ecological Tolerance

The suite of abiotic conditions (such as extremes of temperature, humidity, salinity, sunlight, and water flow) under which a species can survive, grow, and reproduce; also known as the fundamental niche.

Fundamental Niche

The complete suite of abiotic conditions under which an individual or species can survive, grow, and reproduce.

Realized Niche

The range of abiotic and biotic conditions (including competition, predation, herbivory, and parasitism) under which a species actually lives.

Geographical Range

The areas of the world in which a species lives.

Periodic Disruptions

Disruptions that occur regularly on a predictable schedule, such as cycles of day and night.

Episodic Disruptions

Disruptions that occur somewhat regularly, such as cycles of high and low rain occurring every $5\text{ to }10\text{ years}$.

Random Disruptions

Disruptions that occur with no regular pattern, such as volcanic eruptions and hurricanes.

Intermediate Disturbance Hypothesis

The hypothesis stating that ecosystems experiencing intermediate levels of disturbance will favor a higher diversity of species than ecosystems with high or low disturbance levels.

Evolution

A change in the genetic composition of a population over time.

Microevolution

Evolution occurring at the population level, such as the development of different varieties of apples and potatoes.

Macroevolution

Evolution where genetic changes give rise to new species or larger categories of organisms including new genera, families, classes, or phyla.

Evolution by Artificial Selection

The process of evolution where humans determine which individuals to breed, typically with a preconceived set of traits in mind.

Evolution by Natural Selection

The process of evolution where the environment determines which individuals survive and reproduce.

Fitness

An organism's ability to survive and reproduce.

Adaptations

Traits that improve an individual's fitness.

Evolution by Random Processes

Processes that alter the genetic composition of a population over time without being related to differences in fitness among individuals.

What are the 5 random processes:

• Mutation

• Gene Flow

• Genetic Drift

• Bottleneck Effect

• Founders Effect

Mutation

A change in the DNA sequence of an organism's genome, which can lead to new traits.

Gene Flow

The movement of genes between populations due to migration of individuals or gametes. This process increases genetic variation within a population and can alter allele frequencies.

Genetic Drift

a mechanism of evolution characterized by random, chance fluctuations in the frequency of gene variants (alleles) in a population over time

Bottleneck effect

a sharp, chance-driven reduction in the size of a population—often caused by natural disasters or human actions—that severely shrinks its genetic diversity

founders effect

a type of genetic drift that happens when a small group of individuals separates from a larger main population and establishes a new, isolated colony

Allopatric Speciation

The speciation process that occurs when a subset of individuals is separated by geographic isolation and eventually develops reproductive isolation.

Sympatric Speciation

The evolution of one species into two species without any geographic isolation, typically occurring through polyploidy.

Genetically Modified Organism (GMO)

An organism produced by copying genes with a desirable trait from one species and inserting them into another species of plant, animal, or microbe.

Ecological Succession

The predictable replacement of one group of species by another group of species over time in a community.

Primary Succession

Ecological succession that begins in terrestrial communities on newly exposed surfaces with bare rock and no soil.

Pioneer Species

Early successional organisms such as algae, lichens, and mosses that can colonize bare rock and survive with little to no soil.

Secondary Succession

Ecological succession that occurs in areas that have experienced disturbances removing vegetation, such as forest fires or hurricanes, but have retained their soil.

Climax Community

The historically described final stage of ecological succession, such as the oldest forests.

Keystone Species

A species that is not very abundant in an ecological community but has large, disproportionate effects on it.

Indicator Species

A species that demonstrates a particular characteristic of an ecosystem, often used to assess whether ecosystems have been negatively impacted by humans or are rebounding.