-
Linnaeus hierarchical classification scheme
Kingdom to class,order genus and species
-
a group of related species
genus
-
Is the main process that increases the frequency of adaptive traits through time
Natural selection
-
The three operation of natural selection
variation,heritability,and differential reproductive sucess
-
every species is composed of a great variety of individuals,some of which are better adapted to their environment than others
variation
-
offspring inherit traits from their parents,at least to some degree and in some way
heritability
-
better-adapted individuals generally produce more offspring over the generations than poorer-adapted individuals, the frequency of adaptive traits gradually increases in subsequent generations
differential reproductive
-
greater reproductive success in a particular environment
adaptive
-
theory that disadvantageous traits will generally decline in frequency or even disapperar eventually
maladaptive
-
a particular trait seems to be positively favored and the average value shifts over time toward the adaptive trait
directional selection
-
the average value does not change,but natural selection removes the extremes
normalizing selection
-
occurs when a heterozyous(varied) combination of alleles (genes) is positively favored
balancing selection
-
the allele of a gene pair that is always phenotypically expressed in the heterozygous form
dominant
-
an allele phenotypically suppressed in the heterozygous form and expressed only in the homozygous form
recessive
-
-
observable appearance
phenotype
-
Mendel's units of heredity were what we now call
genes
-
each member of a gene pair or group is called an
allele
-
if the two genes,or alleles for a trait are the same the organism is
homozygous
-
if the two genes for a characteristic differ the organism is
heterozygous
-
the genes of higher organisms are located on ropelike bodies called
chromosomes
-
cellular reproduction
mitosis
-
reproductive cells are formed
meiosis
-
deoxyribonucleic acid
DNA
-
direct the formation of proteins
messenger RNA
-
uses the information on the mRNA to make proteins
Ribosome
-
sorting of chromosomess in meiosis
segregation
-
the exchange of sections of chromosomes between one chromosome and another
crossing-over
-
change in the DNA sequence
mutation
-
various random processes that affect gene frequencies in small relatively isolated populations
genetic drift
-
the process whereby genes pass from one population to another through matching and reproduction
gene flow
-
the variation in gene freqency from one end of the region to the other is
cline
-
a population that consists of organisms able to interbreed and produce fertile and viable offsprings
species
-
the creation of a viable offspring from two different species, may be more possible than once thought
hybridization
-
the development of a new species may occur if one subgroup of a species finds itself in a radically different environment
speciation
|
|