environmental variation
variation among individuals is sometimes due to differences in the environment
evolutionary/phylogenetic tree
models the process of evolution as a branching tree w/ a common trunk balances that split off
descent w/ modification
evolutionary changes that have accumulated over time since 2 groups split from each other
nodes
points where one species splits into 2
genetic variation
when genetic material is transmitted from the parents to offspring
evolution
a change in the genetic makeup of a population from one generation to the next
root
the base of the tree, representing the common ancestor of all the groups
selective pressure
describes the full set of environmental conditions, both biotic and abiotic, that allow some organisms to survive and reproduce better than others
natural selection
how population changes over time, but also how they become exquisitely adapted to their environment
tree of life
evolutionary tree of all organisms and has three major branches: bacteria, archaea, eukaryotes
alleles
different forms of a gene
disruptive selection
operates in favor of extremes and against intermediates
dirctional selection
leads to a change in a trait in a population overtime
stabilizing selection
acts against extreme phenotypes and favors intermediate phenotypes
new mutations
harmful and eliminated by natural selection, NO long term evolutionary impact
neutral mutations
does NOT affect survival and reproduction
beneficial mutations
common and result in adaptation to the environment
convergent evolution
process where 2 different species evolve similar traits in response to similar selective pressures
vertebrates
animals like us that have skulls
entomologist
a scientist who studies insects
biodiversity
biological diversity
1st darwin postulate
members of a species vary from one another
2nd Darwin Postulate
some phenotype variation is heritable or passed on to the next generation
3rd Darwin postulate
states that in nature, organisms frequently compete for resources
4th Darwin Postulate
states that variations that increase survival and reproduction will be passed on to individuals in the next generation
intra-sexual
sexual selection focuses on interactions between 1 sex
inter-sexual
selection focuses on interactions between male and females
sexual selection
form of selection that promotes traits that increase an individuals ability to find and attract mates
fitness
ability of an individual to survive and reproduce in the environment in which it lives
on the origin of species
book that brought evolution, natural selection, and adaption to public attention
artificial selection
process where humans select for traits
adaptations
traits of organisms that closely fit their environments