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Chapter Four and Five
Evolution. ect.
42
Environmental Studies
Undergraduate 3
02/28/2011

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Term
Biological Evolution
Definition
consists of genetic change in organisms across gernations. change often leads to change in the appearance
Term
Natural Selection
Definition
the process by which traits that enhance survival and repoduction are passed or more frequently to future generations than those that do not, altering genetic makeup of a population
Term
Charles Darwin/ Alfred Russel Wallace
Definition
They each proposed the concept of natural selection as a mechanism for evolution and as a way to explain the great variety of living things.
Term
adaptive trait/ adaptation
Definition
species will evolve to posses characteristics that lead to better and better success in a given enviroment
Term
mutations
Definition
accidental alterations that arise during DNA replication
Term
artificial selection
Definition
the process of selection conducted under human direction
Term
biological diversity/ biodiversity
Definition
refers to the sum total of all organisms in an area, taking into account the diversity of species, their genes, their populations, and their communities
Term
population
Definition
group of individuals of a particular species that live in the same area.
Term
species
Definition
particular type of organism/ population/ share certain characteristics and can freely breed with one another and produce fertile offspring.
Term
speciation
Definition
new species are generated. due to physical seperation of populations over some geographic distance
Term
phylogenetic trees
Definition
treelike diagrams that explain relationships between among species, major groups of species, populations, or genes.
Term
fossil record
Definition
the cumulative body of fossils worldwide
Term
extinction
Definition
the disappearance of a species from earth
Term
mass extinction events
Definition
killed off massive numbers of species at once
Term
biosphere
Definition
cumulative total of living things on earth and the areas they inhabit
Term
population ecology
Definition
investigates the quantitative dynamics of how individuals within a sepcies interact with one another
Term
community ecology
Definition
interactions among species, from one to one interactions to complex interrelationships involving entire communities.
Term
niche
Definition
a species...reflects its use of resources and its funcitonal role in a community.
Term
specialist
Definition
organisms vary in the breadth of their niche. species with narrow breadth and thus very specific requirements are said to be...
Term
generalist
Definition
those with broad tolerance, able to use a wide array of habitats or resources
Term
population size
Definition
expressed as a number of indivisuals
Term
population density
Definition
describes the number of individuals within a population per unit area
Term
population distribution
Definition
describes the spatial arrangement of organisms within an area, random, uniform, or clumped
Term
limiting factors
Definition
physical, chemical, and biological characteristics of the environment that restrain population growth
Term
logistic growth curve
Definition
rises sharply at first, then drifts as limiting factors become stronger
Term
density independent
Definition
factors are limiting factors whose influence is not affected by population density
Term
k- selected/ r-selected
Definition
k-stabilize near carrying capacity/ r-focus on quantity not quality
Term
resource partionting
Definition
when species divide because they use their resources in different ways
Term
mutualism
Definition
when species benefit from each other
Term
symbiosis
Definition
species in close physical contact/ mutation
Term
community
Definition
assemblage of species living in the same place at the same time
Term
producers
Definition
the first trophic level. plants. energy
Term
consumers
Definition
organisms that consume producers. primary. secondary trophic level. grazing deer/ cattle
Term
decomposers
Definition
detritivores/ consume non-living things.
Term
keystone species
Definition
animal that has a strong impact on life. holds the structure together
Term
succession
Definition
if a disturbance is severe enough to eliminate all or most of the species in a community, the affected site will undergo a somewhat predicatable series of changes that ecologists cal...
Term
secondary succession
Definition
begins when a disturbance dramatically alters an existing community but does not destroy life all together
Term
pioneer species
Definition
animals that are well adapting for colonization, they arrive first and colonate
Term
invasive species
Definition
can alter a community substantially/ one of the central ecological forces into todays world
Term
restoration
Definition
restore it back to its natural position
Term
biome
Definition
a major regional complex of similar communities/ a large ecological unit recognized primarily by its dominant plant type and vegetation structure
Term
deciduous
Definition
lose their leaves
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