APES Unit 3: Ch 3 & 4

Population

A group of individuals that belong to the same species and live in the same area

Species

A population or group of population whose memebers share characteristics and can bread with eachother and produce fertile offspring

Evolution

Change over time; gentic changes lead to changes in apperance, functioning or behavior over generations

Natural Selection

Traits that enhance survival and reproduction

Adaptation

The process where over time, characteristics(traits) that lead to better reproductive success

Mutation

Accidental changes in DNA that may be passed on the next generation

Directional Selection

Drives a feature in one direction

Stabalizing Selection

Favors intermediate traits; preserving the status quo

Disruptive Selection

Traits diverge in two or more directions

Divergent Evolution

Related species in different environments; experience different pressures, evolve different traits

Convergent Evolution

Unreleated species may evovle similar traits; because they live in similar environment

Artifical Selection

The process of selectipn conducted under human direction; producing the great variety of dog breeds and food crops

Biological Diversity (Biodiversity)

The variety of life across all levels of biological organization

Speciation

The process of generating new species from a single species

Allopatric Speciation

Species fromation due to physical seperation of population

Sympatric Speciation

Species form from population that become reproductively isolated within the same area

Phylogenetic Trees (Cladograms)

Show relationships among species, groups, genes, etc.

Fossil

An imprint in stone of a dead organism

Fossil Record

The cumulative body of fossils worldwide

Extinction

The disappearance of a species from Earth, when the environment changes faster than species can keep up

Indicator Species

Species that indicate change

Endemic Species

A species that only exists in a certain, specialized area

Background Extinction Rate

Extinction usually occurs one species at a time

Biosphere

The total living things on Earth, plus the area they inhabit

Community

Interacting species living in the same area

Ecosystem

Communities and nonliving material and forces they interact with

Population Ecology

Investigates the dynamic of population change

Community Ecology

Focuses on patterns of species diversity and interactions

Ecosystem Ecology

Studies living and nonliving components of systems to reveal patterns

Habitat

The type of environment in which an organism or group normally lives or occurs

Habitat Use

Each organism thrives in certain habitats but not others

Habitat Selection

The process by which organisms actively select habitats in which to live

Niche

An organism's use of resources

Specialists

Have narrow niches and specific needs, extremely good at what they do but vulnerable when conditions change

Generalists

Species with broad niches, use wide array of habitats and resources and can live in many different places

Population Size

Number of individual organisms at a given time

Population Density

Number of individuals in a population per unit area

Population Distribution (dispersion)

Spatial arrangement of organisms

Random

Haphazardly located individual's, with no pattern

Uniform

Individuals are evenly spaced; territoriality, competition

Clumped

Arranged according to availability of resources; most common in nature

Sex Ratio

Proportion of males to females; in monogamous species, 1:1 maximizes population growth

Age Distribution (structure)

The relative number of organisms of each age in a population

Age Structure Diagram (pyramid)

Show the age structure of population

Survivorship Curves

The likelihood of death varies by age

Type 1

More deaths at older age

Type 2

Equal number of deaths at all ages

Type 3

More deaths at younger age

Biotic Potential

An organism's capacity to produce offspring

K-Selected Species

Species with long gestation periods and few offspring

R-Selected Species

Species which reproduce quickly

Natality

Births within the population

Morality

Deaths within the population

Immigration

Arrival of individuals from outside the population

Emigration

Departure of individuals from the population

Exponential Growth

A population increases by a fixed percent

Limiting Factors

Physical, chemical, and biological attributes of the environment

Environmental Resistance

All limiting factors taken together, stabilizes population size

Density-dependent Factors

Limiting factors whose influence is affected by population density

Density-independent Factors

Limiting factors whose influence is not affected by population density

Carrying Capacity

The maximum population size of a species that it's environment can sustain

Competition

Both species are harmed; multiple organisms seek the same limited resources

Exploitative

One species benefits and the other is harmed

Mutualism

Both species benefit

Intraspecific Competition

Competition between members of the same species

Interspecific Competition

Competition between members of 2 or more species

Competition Exclusion

One species completely excludes another species from using the resource

Species Coexistence

Neither species fully excludes the other from resources, so both live side by side

Fundamental Niche

The full niche of species

Realized Niche

The portion of fundamental niche that is actually filled

Character Displacement

Competing species diverge in their physical characteristics

Exploitation

One member exploits another for its own gain

Predation

Process by which individuals of one species (predators) capture, kill, and consume individuals of another species (prey)

Parasitism

A relationship in which an organism depends on another (host)

Parasitoids

Insects that parasitize other intersects killing the host

Coevolution

Hosts and parasites become locked in a duel of escalating adaptation

Herbivory

Animals feed on the tissues of plants

Mutualism

Two or more species benefit from their interactions (+/+)

Symbiosis

Mutualism in which the organisms live in close physical contact

Mycorrhizae

Plant roots and fungi

Zooxanthellae

Coral and algae

Adaptive trait

A trait that confers greater likelihood that an individual will reproduce

Charles Darwin

English naturalist who proposed the concept of natural selection as a mechanism for evolution and as a way to explain the great variety of living thins

Demographers

A scientist who studies human populations

Ecology

The science that deals with the distribution and abundance of organisms, the interactions among them and the interactions between organisms and their abiotic environments

Ecotourism

Visitation of natural areas for tourism and recreation. May generate economic benefits

Logistic Growth Curve

A plot that shows how the initial exponential growth of a population is slowed and finally brought to a standstill by limiting factors

Natural Rate of Population Change

The rate of change in a populations size resulting from birth and death rates alone, excluding migration

Population Distribution

The spatial arrangement of organisms within a particular area

Russel Alfred Wallace

English naturalist who proposed, independently of Charles Darwin, the concept of natural selection as a mechanism for evolution and as a way to explain the great variety of living things

Tundra

A biome that is nearly as dry as a desert but is located at very high altitudes along the northern edges of Russia, Canada, and Scandinavia. Extremely cold winters with little day light and moderately cool summers with lengthy days characterize this landscape of lichens and low, scrubby vegetation

Tropical Rainforest

A biome characterized by year-round rain and uniformly warm temperatures. Found in Central America, South America, southeast Asia, west Africa, and other tropical regions. Tropical rainforests have dark, damp interiors; lush vegetation; and highly diverse biotic communities

Tropical Dry Forest

A biome that consists of deciduous trees and occurs at tropical and sub-tropical latitudes where wet and dry seasons each span about half the year. Widespread in India, Africa, South America, and northern Australia

Trophic Level

Rank in the feeding hierarchy of a food chain. Organisms at higher trophic levels consume those at lower trophic levels

Trophic Cascade

A series of changes in the population sizes of organisms at different trophic levels in a food chain, occurring when predators at high trophic levels indirectly promote populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check.

Temperate Rainforest

A biome consisting of tall coniferous trees, cooler and less species rich than tropical rainforest and milder and wetter than temperate deciduous forest

Temperate Grasslands

A biome whose vegetation is dominated by grasses and features more extreme temperature differences between winter and summer and less precipitation than temperate deciduous forest

Temperate Deciduous Forest

A biome consisting of midlatitude forests characterized by broad-leafed trees that lose their leaves each fall and remain dormant during winter. Thes forests occur in areas where precipitation is spread relitvely evenly throughout the year: much of Europe, eastern China, and eastern North America

Succession

A stereotypical series of changes in the composition and structure of an ecological community through time

Secondary Succession

A stereotypical series of changes as an ecological community develops over time, beginning when some vent disrupts or dramatically alters an existing community