Unit 5 Flashcards
spontaneous generation
life can be generated by non-life
biogenesis
all living things come from other living things
morphology
study of shape or physical characteristics of an organism
phylogeny
evolutionary history of an organism
chemosynthesis
inorganic molecules in the early sea combined to form amino acids –> proteins –> cells
homologous structure
structures with similar underlying structure and similar embryonic origin; current functions may be different
analogous structure
structures with similar functions and similar superficial appearance but not the same embryonic origin
coevolution
evolution in two interdependent species in which changes in one group influence changes in the other
niche
specific function a species serves in a habitat or ecosystem
Cambrian explosion
period of rapid speciation among multicellular organisms that occurred about 500 million years ago
natural selection
process by which the environment determines the organisms/traits best adapted to a given environment at a particular time
artificial selection
process of breeding organisms for a particular trait
trait
physical/behavioral characteristics
fitness
degree to which an organism’s traits allow it to survive and reproduce
adaption
evolutionary process by which the genetic makeup of a population changes so that the population becomes better able to survive and reproduce; inherited trait that increases an individual’s fitness
transitional species
fossil species that represent an intermediate stage in the evolution of one species to another
vestigial sturctures
body parts that one time were necessary but now are reduced in size and have no specific function
gene pool
total genetic information available in a population to create the next generation
allele frequency
frequency of certain alleles in populations, change all the time–> when they change = evolution
Hardy-Weinburg genetic equilibrium
observation that the proportions of alleles in the gene pool do not change over time in a population that is not evolving
genetic variation
genetic diversity that is essential to natural selection; produced by mutation, sexual reproduction, and gene flow
directional selection
selection that favors one extreme expression of a trait
negative selection
natural selection that disfavors a particular trait so it becomes very rare in a population
sexual selection
the choice of a mate based on specific and often exaggerated or elaborate characteristics