1.
age pyramids: graphical representations of populations' ages..
2.
alfred wallace: Scientist who also introduced natural selection.
3.
allopatric speciation: The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.
4.
Artificial selection: selection by humans for breeding of useful traits from the natural variation among different organisms.
5.
Biodiversity: the variety of species living within an ecosystem.
6.
carrying capacity: largest number of individuals of a population that a environment can support.
7.
charles darwin: Created the theory of evolution and introduced natural selection.
8.
clumped distribution: distribution where many members of the population live close together.
9.
communitites: all of the populations that live in an area.
10.
community ecology: The study of how interactions between species affect community structure and organization.
11.
density-dependent: Referring to any characteristic that varies according to an increase in population density.
12.
density-independent: limiting factors that affect the population, regardless of the size(abiotic).
13.
directional selection: occurs when natural selection favors one of the extreme variations of a trait.
14.
disruptive selection: natural selection that favors individuals with either extreme of a trait.
15.
ecosystem ecology: The study of energy flow and the cycling of chemicals among the various biotic and abiotic components in an ecosystem.
16.
ecosystems: All the living and non-living things that interect in an area.
17.
evolution: Consists of genetic change in population of organisms across generations.
18.
exponential growth: occurs when the individuals in a population reproduce at a constant rate.
19.
galapagos islands: a group of islands in the Pacific off South America explored by Charles Darwin and Alfred wallce.
20.
geographic speciation: geographic barriers to gene flow leads to evolution of reproductive isolation by natural selection.
21.
habitat: Place where an organism lives.
22.
k-selected: organisms that reproduce later in life, produce fewer offspring, and devote significant time and energy to the nurturing of their offspring.
23.
limiting factors: environmental factors that restrict population growth.
24.
logistic growth: Population growth that is controlled by limited resources.
25.
mass extinctions: mass destruction of most species.
26.
Mutation: Accidental changes in DNA.
27.
natural selection: Is the process by which traits that enhance survival and reproduction ate passed on more frequently to future generations than those that do not.
28.
niche: A species use of resources and its functional role in a community including the environment it needs to survive, its consumption of certain foods, and its interactions with other organisms.
29.
phylogenetic tree: a family tree that shows the evolutionary relationships thought to exist among groups of organisms.
30.
population: a group of organisms of the same species populating a area.
31.
population ecology: The study of populations in relation to the environment, including environmental influences on population density and distribution, age structure, and variations in population size.
32.
r-selected: organisms that reproduce early in life and often and have a high capacity for reproductive growth.
33.
random distribution: distribution in which the location of members in a population is totally random.
34.
specialists: species that have narrow niches.
35.
speciation: formation of a new species.
36.
species: group of similar organisms that can breed and produce fertile offspring.
37.
Stabalizing selection: average steady version of the trait.
38.
surviviorship curves I: Humans with higher death rates at older ages.
39.
survivorship curve II: Is intermediate and indicates equal rates of death at all ages.
40.
survivorship curve III: Toads with the highest death rates at young ages.
41.
sympatric speciation: The formation of new species in populations that live in the same geographic area.
42.
uniform distribution: a distribution whose shape is evenly distributed throughout the values it takes.
