Unit 7: Chapter 24 Flashcards
macroevolution
evolutionary change above the species level
anagenesis
phyletic evolution
transforms one species into another
cladogenesis
branching evolution
the splitting of a gene pool
gives rise to one or more new species while retaining the original species
biological species
reproductively compatible
they cannot interbreed with other species
their offspring are fertile
reproductive isolation
the existence of biological factors or barriers that impede two species from producing viable, fertile hybrids
two types of biological factors
prezygotic and postzygotic
five kinds of prezygotic barriers
habitat isolation
temporal isolation
behavioral isolation
mechanical isolation
genetic isolation
habitat isolation
two species occupy different habitats
temporal isolation
two species breed at different times of day or season
behavioral isolation
certain courtship rituals of behaviors prevent species from mating with others
mechanical isolation
physical differences prevent successful mating
gametic isolation
the sperm of one species can’t fertilize eggs of another
prezygotic barriers
impede mating or hinder fertilization if mating does occur
postzygotic barriers
prevent the hybrid zygote from developing into a viable, fertile adult
three types of postzygotic barriers
reduced hybrid viability
reduced hybrid fertility
hybrid breakdown
reduced hybrid viability
genes of the different parent species interact and impair the hybrid’s development
reduced hybrid fertility
hybrids can still be sterile even if they survive
hybrid breakdown
some first generation hybrids are sterile but the second generation is not
allopatric speciation
gene flow is interrupted when a population is divided into geographically isolated subpopulations
reproductive isolation must be established
sympatric speciation
speciation takes place in geographically overlapping populations
happens through polyploidy and autopolyploidy and allopolyploidy
polyploidy
the presence of extra sets of chromosomes due to accidents during cell division
autopolyploidy
an individual has more than two chromosomes sets derived from the same species
allopolyploidy
individual has multiple sets of chromosomes derived from different species
adaptive radiation
the evolution of diversely adapted species from a common ancestor
occurs due to introduction to new environmental opportunities and challenges
punctuated equilibrium
periods of continuity punctuated by sudden change
heterochrony
evolutionary change in the rate or timing of developmental events
can have a significant impact on body shape
allometric growth
the proportioning that helps give a body its specific form
paedomorphosis
the rate of reproductive development accelerates compared to somatic development
a sexually mature species may retain body features that were juvenile structures in an ancestral species
speciation
the origin of new species
