macroevolution - exam 4 Flashcards
macroevolution
major evolutionary changes over a longer period of time
above population level
how can you assess the time interval between speciation events
use fossils & molecular data
causes of changes in diversity
intrinsic properties of the species
large scale changes in climate or environment
gradualism
slow & steady change
punctuated equilibrium
periods of little change interrupted by rapid periods of short change
adaptive raadiation
periods of time when many new species formed
often happen when there are ecological niches to fill (after extinctions or new land)
conditions for adaptive radiation
availability of ecological niches
isolation or dispersal
rapid evolution
ecological release
new adaptive traits
stable environment
reduced gene flow
conditions that promote rapid evolution
high mutation rates
short generation time
strong selective pressures
ecological release
when species experience a decrease in competition or predators
undergo ecological release
allows them to exploit new resources
how many mass extinctions
5
in the 6th
consequences of mass extinctions
open up niches for new species
