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Describe the conditions of primitive earth.
- very hot and hostile
- lots of geologic activity
- most of the planet's water was in the form of vapor
- as the planet cooled, water began to fall as rain
List the three most widely accepted theories for where the first organic material came from.
- chemical reaction due to geothermal events
- comet or meteorite deposited the organic matter here
- atmospheric reaction created organic material
Where did life begin?
in the water
What type of organism migrated to land first?
What did algae develop that allowed them to survive on land?
What organisms followed plants onto land?
What type of invertebrates likely came onto land first?
List two reasons that organisms would migrate onto land.
- in search of food
- to avoid predators
As fish adapted to stay on land longer and longer, they gave rise first to ______ and later to _______ species.
List in order the major classes of organisms that migrated to land.
List the four Pre-Darwin ideas discussed in class.
- the earth is very young, age measured in 1,000's
- all organisms are specially created, no new species will be added, and no existing species will vary
- any ability to adapt is the work of a creator
- all observations should support the current world view
What did Linneaus contribute to the study of organismal evolution?
What does taxonomy examine?
relationships between organisms
study of the fossil record
Who was an early pioneer in paleontology?
What did Cuvier notice about the fossil record?
that some animals were disappearing
The idea that any time an animal goes extinct it must be due to a major disaster or geologic event is the:
Theory of Catastrophism
Who developed the Theory of Gradualism?
Explain the Theory of Gradualism.
extinction and other biological events happen slowly over time
What were Lamarck's two theories?
- use and disuse - animals lose characteristics they do not use and develop characteristics they require
- individuals inherit the acquired traits of their ancestors
Where did Darwin sail?
around the southern hemisphere
Darwin left on a voyage in 1831 aboard what ship?
the HMS Beagle
What two tasks was Darwin supposed to be doing while on his voyage.
- serving as ship naturalist
- finding evidence to support Creationism
Where did Darwin do a majority of his research?
the Galapagos Islands
True or False - The Galapagos Islands were useful to Darwin due to the ample variation in habitat among the islands.
What two species did Darwin concentrate his efforts upon?
tortoises and finches
What two things did Darwin observe?
- observed enough similarity to assume a common ancestor
- observed enough disparity to assume adaptation
Upon returning to England, Darwin wrote what text?
Theory of Evolution
True or False - Darwin published Theory of Evolution upon returning to England.
False - Darwin did not publish it until much later in life
What were the four Post-Darwin ideas discussed in class?
- the earth is very old, age measured in billions of years
- species are related by descent
- adaptations are related to environment, change, and random mutation
- observations should reflect the natural world
What are the three preconditions for natural selection?
- members of a population have variations that can be passed to offspring
- within a population, more offspring will be produced than the environment can support
- some organisms will have adaptive characteristics that make them more fit, and more likely to pass on their genes
What is the carrying capacity?
the number of organisms an area of resources can support
What are the outcomes of natural selection?
- over time, an increasing number of individuals should have the "fitter" characteristics
- members of a population will become more and more fit, with regards to their environment, with each passing generation
In what two ways does the fossil record support evolution?
- ability to observe the change in a species over time - horses
- ability to see links between species - Archaeoptyerx
Can we use genetic information to support evolution?
yes, by means of DNA testing
How do we use anatomic evidence to support evolution?
- by comparing evidence of similar bones with different uses in species
- notably, the forearm in vertebrates
What is a homologous structure?
a structure that is anatomically similar due to a common ancestor
What are analogous structures?
structures that serve the same function, but with different morphology
What is a vestigial structure?
a structure that is fully developed and used in one species, and underdeveloped or not used in another
Give an example of an analogous structure.
bird wing and a bat wing
Give two examples of vestigial structures.
- appendix in humans
- coccyx in humans
- wings in ostriches
What is a population?
all the members of a species in a given area
What are population genetics?
the study of genetic change in a population
What is the gene pool?
the total of all alleles, in all the individuals, for a population
What is microevolution?
the accumulation of small changes in alleles in the gene pool that happens over a relatively short time
How do peppered moths demonstrate microevolution?
Their color reacts to changes in the environment due to industrialization. The shift happens faster than normal selection of traits.
List five causes of microevolution.
- environmental change
- genetic mutation
- gene migration
- non-random mating
- genetic drift
Explain genetic mutation.
- mutations lead to an initial increase in variation
- some mutations will be more successful than others
- mutations that are more successful will be passed on more often and variation will decrease
Explain gene migration.
occurs when breeding individuals migrate to another population
When a black male migrates and breeds with a white woman, he adds his alleles to the "white" gene pool. This is an example of:
What is random mating?
mating that occurs without phenotypic preference
What is non-random mating?
mating that is not due to chance, occurs as a result of phenotypic preference
What are the two types of non-random mating discussed in class?
- assortive mating - based on similar phenotype
- sexual selection - males compete for females
How can genetic drift cause microevolution?
the allele frequency can change due to chance or other geophysical factors
What happens when a bottleneck effect occurs?
a large population, for whatever reason, only has a few individuals who successful produce the next generation, quickly lowering the allele variation of the population
What is the founder effect?
occurs when a founding member of a isolated population has a rare allele that would be uncommon in a larger population, but because of the small, isolated group becomes more prevalent
Give a modern day example of the founder effect.
dwarfism and polydactyl in Pennsylvania Amish
Define natural selection.
survival of those possessing the greatest ability to adapt to biotic and abiotic conditions
What is directional selection?
occurs when on extreme phenotype is favored and the population shifts, over time, towards that phenotype
How does stabilizing selection work?
populations shift, over time, towards the intermediate phenotype and away from extremes
When both extremes of phenotype are favored and the population shifts away from the middle towards them, you have this type of selection.
What is a species?
members of a shared gene pool that are able to breed and create viable offspring
What is speciation?
separation of a species into two new species
When speciation occurs due to a random allele change, you have what kind of speciation?
When speciation results due to a physical or geographic barrier between members of the parent species you have this kind of speciation.
The differences in Old World and New World monkeys are the result of ________ speciation.
True or False - Isolation is/are a set of circumstances that work to keep species separate.
Organisms that cannot physically mate or produce viable offspring exhibit this type of isolation.
List the four types of prezygotic isolation.
When organisms reach fertile periods at different times of the year, they are said to exhibit this type of isolation.
Members of a species who live in different environments are _______ isolated.
When a specific courtship pattern fails to impress a female, mating does not succeed due to _________ isolation.
Mechanical isolation occurs when reproductive structures are:
When two organisms create a hybrid offspring that are infertile or fail to mature to reproductive age we see this type of isolation.
What are the two types of postzygotic isolation discussed in class?
- decreased hybrid viability
- decreased hybrid fertility
Decreased hybrid viability occurs when a hybrid organism doesn't:
survive to reproductive age
When a hybrid organism is not capable of reproducing it demonstrates this type of postzygotic isolation.
decreased hybrid fertility
Why can't mules reproduce?
they possess an odd number of chromosomes which prevents correct gamete formation