Unit 2 Study Guide

Vocabulary flashcards covering key terms and definitions from Unit 2 lecture notes on biodiversity, ecosystems, species interactions, evolution, and ecological succession.

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem. Three types: ecosystem, species, genetic.

Species Biodiversity

Represents the number of different species living in an area.

Genetic Biodiversity

The total number of genetic characteristics in the genetic makeup of a species (higher gen. biodiversity makes populations more resistant to disturbance).

Ecosystem Biodiversity

Refers to the variety of ecosystems found in a given area.

Habitat

The natural home or environment of an animal, plant, or other organism.

Ecosystem

A biological community of interacting organisms and their physical environment. (abiotic + biotic).

Specialist Species

Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food (e.g., pandas).

Generalist Species

Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions (e.g., cockroaches, mice, rats, and human beings).

Biodiversity Hotspots

Relatively small areas of land that contain an exceptionally high number of species and are at high risk from human activities.

Ecosystem Services

Important environmental benefits, such as clean air to breathe, clean water to drink, and fertile soil for growing crops, that ecosystems provide (have a monetary value to humans).

Provisioning Services

Benefits of biodiversity that humans use, including lumber, fur, meat, crops, water, and fiber.

Regulating Services

The service provided by natural systems that helps regulate environmental conditions (e.g., trees removing carbon from atmosphere and roots filtering ground water).

Supporting Services

The basic ecosystem processes, such as nutrient cycles and soil formation, that are needed to maintain other services like agriculture (e.g., bees, moths pollinating agricultural crops).

Cultural Services

Ecosystems provide cultural or aesthetic benefits to many people (e.g., tourists willing to pay to visit nature, or scientists conducting research that leads to new knowledge).

Anthropogenic

Caused by humans.

Ecological

Relating to or concerned with the relation of living organisms to one another and to their physical surroundings.

Island Biogeography Theory

Explains how species come to be distributed among oceanic islands.

Limited Resources

The condition of there not being enough resources to fulfill the needs of all organisms in a given area (food, shelter, water).

Invasive Species

Plants and animals that have migrated to places where they are not native. Often outcompete natives (e.g., zebra mussel, asian carp, kudzu vine).

Native Species

Species that normally live and thrive in a particular ecosystem.

Zebra Mussel

A small freshwater mollusk with zigzag markings on the shell. Introduced to US by large ships traveling over from Europe. Reproduce rapidly and outcompete natives for algae (food source).

Colonization

The process of a species migrating to a new habitat such as an island.

Ecological Tolerance

The ability of a species to survive and reproduce under a range of environmental circumstances (generalists are more tolerant compared to specialists).

Range of Tolerance

Range of chemical and physical conditions that must be maintained for populations of a particular species to stay alive and grow, develop, and function normally.

Natural Disturbances/Disruptions

All natural events that destroy or damage an ecosystem; fires, hurricanes, tornadoes, droughts, floods.

Anthropogenic Disturbances/Disruptions

Human-caused disturbances to ecosystems. Often negatively impacts biodiversity. Timber harvesting, pollution, overgrazing, introducing invasive species, and development.

Periodic

Describes an event that occurs or repeats at regular intervals (e.g., seasons, night & day).

Episodic

Describes an event that happening in parts or segments or that kicks off a flow of related events (e.g., eutrophication, overhunting by humans).

Random

Something that occurs randomly (e.g., hurricanes, lightning strikes, etc.).

Migration

Movement of organisms from one habitat to another. Sometimes permanent (when their habitat is destroyed or disturbed) or temporary (for mating, feeding, or seasonal reasons).

Sea Level

The average level of the ocean's surface at any given time. Has changed significantly over time based on amount of glacial ice and polar ice.

Geologic Time Scale

Scale used by paleontologists to represent evolutionary time.

Resistance

Measure of how much a disturbance can affect the flow of energy and matter in an ecosystem. Ecosystems with high resistance are not as vulnerable to natural and anthropogenic disturbances.

Resilience

The rate at which an ecosystem returns to its original state after a disturbance. The more resilient, the faster an ecosystem returns to its normal state after a disturbance.

Adaptation

A characteristic that improves an individual's ability to survive and reproduce in a particular environment.

Genetic Diversity

A measure of the genetic variation among individuals in a population (higher gen. diversity leads to greater rate of evolution).

Genotype

An organism's genetic makeup.

Phenotype

An organism's physical appearance, or visible traits.

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Leads to evolution of new traits (microevolution) and new species (macroevolution).

Evolution

Changes in a species over time driven by natural selection. Can lead to new traits or entirely new species. INDIVIDUALS DO NOT EVOLVE. SPECIES EVOLVE.

Speciation

The formation of new and distinct species in the course of evolution.

Species

A group of similar organisms that can breed and produce fertile offspring. Different species cannot breed with each other.

Reproductive Isolation (Sympatric Speciation)

Differences in behavior or morphology that prevent organisms from breeding with each other (e.g., different mating calls in birds or different structures in flowers in plants).

Geographic Isolation (Allopatric Speciation)

Two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water. This prevents them from breeding with each other and leads them to evolve into different species.

Ecological Succession

Gradual change in living communities that follows a disturbance.

Primary Succession

Succession that occurs on surfaces where no soil exists (bare rock being colonized by moss & lichen, broken down into soil, & eventually colonized by grasses and shrubs).

Secondary Succession

Succession following a disturbance that destroys a community without destroying the soil (often times a fire or windstorm).

Pioneer Species

Hardy, first species to populate an area during primary or secondary succession (e.g., moss & lichens, small grasses, shrubs, and small trees).

Climax Species

Species that move into an area at later stages of ecological succession. Slower growing species that include large trees.

Keystone Species

A species that has an unusually large effect on its ecosystem. It influences the survival of many other species in an ecosystem, often by creating habitats (e.g., beavers) or controlling herbivores (e.g., wolves).

Indicator Species

Species that serve as early warnings that a community or ecosystem is being degraded (think of the canary in the coal mine).