Chapter 13
Darwinian Evolution
·
Before
Darwin, species were considered as “unchangeable” – although many scientists
had begun to privately question this notion.
·
Darwin
was one of the first to publically challenge that species were fixed and
unchanging
o
Resulted
from the observations he made while on the ship HMS Beagle.
o
22
years after his return, in 1858, he published On the Origin of Species by Means of Natural Selection
o
Never
used the term “evolution!”
o
Principles
of Darwinian Evolution
§
More
individuals are born into a population than can survive on
_______________________
§
Members
of a population differ from one another _____________________
§
Some
of these differences give individuals ___________________
§
These
individuals will tend to pass these advantages onto their offspring
§
Over
time, the population will change
o
Natural
Selection works on the same principle as ________________________
Evidence of Evolution
·
Fossils
·
Biogeography
·
Comparative
Anatomy
·
Molecular
Biology
Causes of Evolution
· Definition of evolution
o “change _______________”
o “change in ___________________________ in a population over time”
· Individuals DO NOT evolve – _____________ evolve
o So how do populations change?
· Sources of change
o Mutation is the ultimate source
o Immigration and emigration alter ______________________
o Sexual reproduction leads to different combinations of alleles, which may lead to a new expression of traits
o Natural selection – not all individuals have equal _________________
o Genetic drift (common in small populations)
o Bottlenecks
o Non-random mating
Natural
Selection & Evolution
· Natural selection leads to ______________ evolution
o Individuals that are better suited to survive and breed pass their traits on to future generations
o “Survival of the fittest” refers to ______________ fitness
§ The likelihood that an individual will contribute to the next generation
· Selection can occur in several different manners
o ______________ Selection
o ______________ Selection
o ______________ Selection
· Sexual selection is obvious in many animals
o Females choose males with certain traits more frequently
Terminology: systematics, taxonomy,
classification, binomial nomenclature, genus, specific epithet, species,
monophyletic group, cladistics, synapomorphic
character, cladogram, Darwinian evolution, natural
selection