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42 terms

CH. 5 - Evolution, Biodiversity, and Population Ecology

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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.