Unit 5 Evolution of Biodiversity

species richness

the number of species in a given area

species evenness

the relative proportion of individuals within the different species in a given area

phylogeny 

the branching pattern of evolutionary relationships

branch point

where speciation took place, like when one species led to the evolution of one or two more species

evolution

a change in the genetic composition of a population over time

microevolution

evolution below the species level

ex. the different types of apples

macroevolution

evolution that gives rise to new species, genera, families, classes or phyla

genes

a physical location on the chromosomes within each cell of an organism

genotype

the complete set of genes in an individual

phenotype

a set of traits expressed by an individual

ex. eye color

mutation

a random change in the genetic code produced by a mistake in the copying process

recombination

the genetic process by which one chromosome breaks off and attaches to another chromosome during reproductive cell division

artificial selection

the process in which humans determine which individuals breed, typically with a preconceived set of traits in mind

ex. some weeds and bacteria will become resistant to herbicide and antibiotics

natural selection

the process in which the environment determines which individuals survive and reproduce

Wallace and Darwin synthesized it

fitness

an individual’s ability to survive and reproduce

adaptation

a trait that improves an individual’s fitness

gene flow

the process by which individuals move from one population to another an thereby alter the genetic composition of both populations

ex. declining Florida panthers gained genetic diversity after Texas panthers were introduced

genetic drift

a change in the genetic composition of a population over time as a result of random mating

ex. the less common black mice may not find a mate and therefore the gene for black mice will be lost

bottleneck effect

a reduction in there genetic diversity of a population caused by a reduction in its size

extinction

the death of the last member of a species

founder effect

a change in genetic composition of a population as a result of descending from a small number of colonizing individuals

ex. a small grp of Amish settlers from Germany carried a mutation that increased

allopatric speciation

the process of speciation that occurs with geographic isolation

sympatric speciation

the evolution of one species into two, without geographic isolation

geographic isolation

physical separation of a grp of individuals from others of the same species

reproductive isolation

the result of two populations within a species evolving separately to the point that they can non longer interbreed and produce viable offspring

genetically modified organism (GMO)

an organism produced by copying genes from a species with a desirable trait and inserting them into another species

range of tolerance

the limits to the abiotic conditions that a species can tolerate

fundamental niche

the suite of abiotic conditions under which a species can survive, grow, and reproduce

realized niche

the range of abiotic and biotic conditions under which a species actually lives

distribution

areas of the world in which a species lives

niche generalist

a species that can live under a wide range of abiotic or biotic conditions

niche specialist

a species that is specialized to live in a specific habitat or to feed on a small group of species

mass extinction

a large extinction of species in a relatively short period of time

sixth mass extinction: anthropocene, human caused extinction