CH. 5 - Evolution, Biodiversity, and Population Ecology

42 terms by R-pastor 

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evolution

Consists of genetic change in population of organisms across generations.

Mutation

Accidental changes in DNA.

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.

charles darwin

Created the theory of evolution and introduced natural selection.

alfred wallace

Scientist who also introduced natural selection.

galapagos islands

a group of islands in the Pacific off South America explored by Charles Darwin and Alfred wallce.

directional selection

occurs when natural selection favors one of the extreme variations of a trait.

Stabalizing selection

average steady version of the trait.

disruptive selection

natural selection that favors individuals with either extreme of a trait.

Artificial selection

selection by humans for breeding of useful traits from the natural variation among different organisms.

Biodiversity

the variety of species living within an ecosystem.

species

group of similar organisms that can breed and produce fertile offspring.

population

a group of organisms of the same species populating a area.

speciation

formation of a new species.

allopatric speciation

The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.

geographic speciation

geographic barriers to gene flow leads to evolution of reproductive isolation by natural selection.

sympatric speciation

The formation of new species in populations that live in the same geographic area.

phylogenetic tree

a family tree that shows the evolutionary relationships thought to exist among groups of organisms.

mass extinctions

mass destruction of most species.

communitites

all of the populations that live in an area.

ecosystems

All the living and non-living things that interect in an area.

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.

community ecology

The study of how interactions between species affect community structure and organization.

ecosystem ecology

The study of energy flow and the cycling of chemicals among the various biotic and abiotic components in an ecosystem.

habitat

Place where an organism lives.

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.

specialists

species that have narrow niches.

clumped distribution

distribution where many members of the population live close together.

uniform distribution

a distribution whose shape is evenly distributed throughout the values it takes.

random distribution

distribution in which the location of members in a population is totally random.

surviviorship curves I

Humans with higher death rates at older ages.

survivorship curve II

Is intermediate and indicates equal rates of death at all ages.

survivorship curve III

Toads with the highest death rates at young ages.

age pyramids

graphical representations of populations' ages..

exponential growth

occurs when the individuals in a population reproduce at a constant rate.

logistic growth

Population growth that is controlled by limited resources.

carrying capacity

largest number of individuals of a population that a environment can support.

limiting factors

environmental factors that restrict population growth.

density-dependent

Referring to any characteristic that varies according to an increase in population density.

density-independent

limiting factors that affect the population, regardless of the size(abiotic).

r-selected

organisms that reproduce early in life and often and have a high capacity for reproductive growth.

k-selected

organisms that reproduce later in life, produce fewer offspring, and devote significant time and energy to the nurturing of their offspring.

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