Ch. 18 Flashcards
Evolution and Origin of Species
Adaptation
A structural, “physiological”, or behavioral trait that enhances and organisms survival and reproduction in its environment
Jean Baptiste Lamarck
published book that detailed evolutionary change mechanisms
suggested change within lifetime, wrong
Natural Selection
Prolific reproduction of favorable traits because they can survive better in the environment
When did Darwin travel on the HMS Beagle
1831 to 1836
Seed eating finches
larger, thicker beaks
Insect eating finches
spear like beaks
Three principles that operate in nature
- characteristic of organisms are inherited
- more offspring are produced than are able to survive, therefore they are in competition for limited resources
- offspring vary regarding their characteristics and those variations are inherited
Three principles lead to changes in population that Darwin termed
decent with modification
On the Origin of Species Author and Date
Charles Darwin
1858
Natural selection can only take place if there is what in the population
variation
Differences must have
genetic basis
genetic diversity is established by
sexual reproduction and mutations
Mutations
Change in DNA
can reduce fitness
Adaptations increase
fir to the environment
Divergent evolution
two species that evolve in diverse directions from a common point
Convergent evolution
bat and insect wings are used for flight, but evolved separately and do not share common ancestry
Evidence of evolution
fossils, anatomy and embryology, convergence of form, biogeography
Homologous structures
similar appendages, synonymous parts
Vestigial structures
structures that appear to have no function, residual parts from a past ancestor
Homoplasy
similar characteristics that occur independently of evolutionary relationship
Convergence of form
unrelated animals (arctic fox and bird)
display seasonal white phenotypes to blend in
no common ancestry but selection pressure from predators are similar
Endemic species
species found in one place, no where else
