Studied by 1 personWhat is evolution in biology?
process of biological changes by which descendants come to differ from their ancestors
Who was Charles Darwin?
Wrote “One the Origin of Species”
Observed many species on the Galapagos Islands
What were his main observations/studies?
Noticed the variation of traits among similar species
Species found on the island looked diff from those found on nearby islands
Galapagos tortoises and finches
He believes that these species adapted to their environment
What is the difference between variation and adaptation?
difference in physical traits of an individual from those of other individuals
vs
a feature that allows an organism to survive better in its environment
What is biological fitness?
ability to survive and produce more offspring
What is natural selection?
mechanism of evolution, individuals that have beneficial adaptations produce more offspring
( environment is selective agent)
How is it connected to evolution?
It can explain how natural selection occurs
natural selection is the mechanism of evolution
What is the selective agent in natural selection?
environment
What are some examples of natural selection?
giraffes evolving long necks for food
jaguars (check the slides)
What is artificial selection?
When humans change a species by breeding it for certain traits
(humans are the selective agent)
What is the selective agent in artificial selection?
humans
What are some examples of artificial selection?
Dog breeding
What are the four principles of natural selection?
Overproduction - population creates more offspring that can survive and reproduce
Variation - individuals in a population differ from each other
Adaptation - Some individuals in a population get a trait that makes them better able to survive
Descent w Mod. - organisms with a beneficial adaptation are more likely to survive and reproduce and pass on that trait
What are some misconceptions about natural selection and evolution?
That they are the same thing
organisms are always getting better through evolution
What are the sources of evidence for evolution and HOW do they support the theory of evolution?
fossils
embryology
geography
anatomy
(HOW) Fossils
Show the progression of evolution
prove the existence of now extinct past species which are related to present day species
(HOW) Embryology
Similar patterns in embryonic development provide evidence that organisms have descended from a common ancestor
(HOW) Biogeography
grouping of uniquely similar organisms are found in a pattern that prove that they evolved from a common ancestor
(HOW) Anatomy
provides evidence by homologous structures
What are fossils?
the preserved remains of plants and animals whose bodies were buried in sediments
What is biogeography?
the study of geographical distribution of organisms
What is comparative anatomy?
study of the body structures of different species in order to understand the adaptive changes they have undergone
Homologous structure
similar structures but diff function
(body parts of diff species) Ex: Cat and Human Arm
Analogous structure
structures that perform a similar function but aren’t similar in origin
Ex: bat wings and insect wings
Vestigial Structures
Remnants of organs or structures that had a function in an early ancestor
Ex: ostrich wings
Which of these structures can serve as evidence for evolution and why?
What are the other sources of evolution besides natural selection?
Mutations
Gene Flow
Genetic Drift
Sexual Selection
What is allele frequency?
Ratio of one allele to the total number of the alleles for that gene in the gene pool
How does genetic variation occur in a population?
Mutation:
M: can be passed on to offspring
M: increases genetic variation in a gene pool
Gene flow
increases the genetic variation of receiving population
What are the two processes that can allow genetic drift to occur?
Bottleneck effect: genetic drift that occurs after an event greatly reduces the size of a population
Founder effect: genetic drift that occurs after a small number of individuals colonize a new area
What is sexual selection?
occurs when certain traits increase mating success
Intrasexual
involves competition among males
Intersexual
Males display certain traits that attract the female
5 factors that lead to Evolution
Natural Selection
Genetic Drift
Gene Flow
Mutation
Sexual Selection
Who was Alfred Wallace?
Helped Darwin research and theorize on evolution
What are the two methods of dating fossils?
Relative Dating
Radiometric Dating
What is speciation?
the rise of two or more species from one existing species
What is reproductive isolation and the three causes of it? (give an example)
occurs when members of different populations can no longer mate successfully, the final step in becoming two separate species
Behavioral
Geographic
Temporal
Behavioral Isolation
caused by diffs in courtship or mating behaviors
Geographic Isolation
physical barriers that divide a population into 2 or more groups
Temporal Isolation
when timing prevents reproduction between populations
What are mass extinctions vs background extinctions?
occurs suddenly, usually because of a catastrophic event
vs
extinction that occurs continuously but at a very low rate
What is taxonomy?
a system of naming and classifying organisms based on shared characteristics and universal rules
What is the order of classification? (Kingdom → Phylum → Class, etc.)
Kingdom
Phylum
Class
Order
Family
Genus
Species
What methods do scientists use to classify species?
fossil
dna sequence
physical features
