Ch.25 Flashcards
What is gradualism?
Species diverge slow and steady overtime
What is punctuated equillibrium?
Long periods of stasis, then moment of quick change
- little to no morphological change
What happens if have both gradualism and punctuated equilibrium?
Genetic changes are gradual
Morphological changes are spurts
- the genetic changes is gradual and then there is enough changes that it looks like a spurt or morphological change
How many gene changes result in a new species?
1-> few -> a lot of genes change
What is Microevolution?
Changes overtime in a gene pool
What is Macroevolution?
Patterns of evolutionary change over long periods of time
- big change in organisms
What are the mechanisms for Macro and Micro evolution?
Mutations
Natural selection
Genetic drift
Genetic flow
What is speciation and its mechanism?
Development of new species
Mech: reproductive isolation
- allopatric
- sympatric
What is Macroevolution and the effects of it?
Patterns of evolution over large time scales
New biochemical processes
- photosynthesis
New structures
- endoskeleton, early animals had external skeleton
New groups of organisms
- terrestrial vertebrates
- mammals: mammalary glands
- flowering plants
- Prokaryotes -> eukaryotes (bacteria to all organisms)
Increase in diversity of “short” time periods (bursts)
- adaptive radiation
What are examples of Macroevolution?
The emergence of terrestrial vertebrates through a series of speciation events
The impacts of mass extinction on biodiversity
The origin of key adaptations like flight
What is adaptive radiation?
Lost of diversification over short period of time
- periods of evolutionary change in which groups of organisms form many new species who adaptations allow them to fill different ecological roles in their community
Rapid emergence of many species from a single species in “short” time
Large increases in diversity of life have resulted from ________that followed mass extinctions
Adaptive radiation
When does adaptive radiation occur? 4 ways.
- After a mass extinction
- After development of major new structures (photosynthesis, backbone)
- After migration into new area with little competition (the new fishes and bird in Galápagos Islands)
- Specialization ( diff/new food sources)
why is evolution NOT goal oriented?
Populations do not evolve to do something, if they don’t survive they, new forms arise by modification of the existing structures (changes in genes) and then they survive
what are the three key points of evolution that support it is NOT goal oriented
It is for organisms suited for life in their environment
There are many shared characteristics of life
There is diversity of life (all undergo cellular respiration)
