Hypothesis
Specific, testable, rejectable statements
Organismal level
Individuals
Population level
Individuals of the same species
Community level
Populations of multiple different species
Ecosystem level
Community and all of its abiotic factors
Biosphere
All ecosystems
Differential survival/reproduction
The quality of a heritable trait to influence the survival and reproduction of the individual. Required for natural selection
Adaptation
A heritable trait that increases the relative fitness of individuals having the trait.
Genetic homology
similar gene sequences between individuals of different species
Developmental Homology
similarities in morphology of embryos of different species
Structural Homology
similarities in structure of body parts of different species.
Contrivance
Adaptation that exists because of the modification of an original or previous adaptation in an ancestor
Exaptation
Adaptation that exists in an ancestor which will eventually become a contrivance (exaptation is the basis for contrivance)
Vestigial trait
A trait the entire species has that is no longer used or has no use in the
present environment, but was likely an adaptation for an ancestor.
Atavism
a trait possessed by only a few members of the population that is no longer
used, but was likely an adaptation for an ancestor.
Homoplasy
different from homology. where organisms have traits in common, not because of a common ancestor, but as a result of convergent evolution or another factor.
Genome
all of the hereditary information within an individual (includes non-gene
stretches of DNA)
Gene pool
all the alleles of all the genes within a population. Each individual has only a
small set of the genes in the population, unless the population is made of clones.
Genotype
all of the alleles of all the genes within an individual or may refer to a
specific set of alleles of a set of genes under study (compare Phenotype).
Genes
section of DNA found on chromosomes that encodes for a polypeptide, which, in
turn, causes (directly or indirectly) a trait (phenotype), may also regulate the activity of other genes.
Locus
the location of a gene on a chromosome. In a population the locus for a specific gene is considered to be the same throughout.
Alleles
particular versions of a gene that occur at the same locus on homologous
chromosomes.
Homologous pairs of chromosomes
One copy of the same chromosome from each parent (2 sets).
