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What is taxonomy?
Identification,naming and classification of species
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Biological vs morphological species
concepts- what are they
- Biological
- species concept: recognizes species based on genetic interbreeding. A biological species members can interbreed
- with each other in nature to produce fertile offspring
- -Advantages: strong
- evolutionary significance, genetically based
- -Disadvantages:
- large information requirement. What abut
- asexual species or fossils?
- Morphological
- species concept: recognizes species based on differences in appearance
- -Advantages:
- low information requirement, easily understood by everyone
- -Disadvantages:
- some very different organisms have similar appearances, and other organisms in
- interbreeding populations may look very different from each other
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What are prezygotic reproductive
barriers, and what are the types (be able to recognize from examples)?
Prezygoticreproductive barriers: preventing mating or fertilization between species
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What are the postzygotic barriers and generally what do they involve?
- 1.
- temporal
- isolation: individuals do not mate at the same time of year
- 2.
- habitat
- isolation: individuals do not live in the same place and therefore do not
- encounter one another to mate
- 3.
- behavioral
- isolation: individuals do not use the same cues to mate (ex. Fireflys blinking
- patterns)
- 4.
- mechanical
- isolation: sexual organs are incompatible
- 5.
- gametic
- isolation: sperm and egg do not fuse due to cellular incompatibility (surface
- recognition)
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Allopatric vs sympatric speciation
- Allopatric speciation: speciation due togeographical isolation
- Sympatric speciation: speciation withoutgeographical isolation
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What has to happen for speciation to occur using the biological species concept?
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What are the two ideas about the rate of speciation? Which is
supported by the evidence?
Rate ofspeciation: two contrasting patterns1. gradual paceof speculation: big changes (speciation) occur by the steady accumulation ofmany small changes2. puncturedequilibria: long periods of little noticeable changes interrupted (punctuated)by brief periods of rapid change
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What is exaptation?
When oldstructures are used for new functions
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What is paedomorphosis?
Retention of juvenile in and adult
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What are homeotic genes, and why do they explain major changes
in body form in evolution?
Homeotic genes: regulate the rate, timing andspatial pattern of development
-a homeotic gene mutation can drastically changebody plans
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What is macroevolution?
majorevolutionary change. The term applies mainly to the evolution of wholetaxonomic groups over long periods of time.
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4 eras for life on Earth: names, relative order, what marks their start/end, relative time span, major landmarks (only the information provided in class)
- Precambrian era: 46000-542 Million yrs ago
- -very long-4.1 billion yrs
- -age of prokaryotes
- -algae and aquatic invertabrates
- -oldest animals and eukaryoktes
- Paleozoic era: 542-241 million yrs ago
- -second longest -291 million years
- -most animal groups appear
- -colonization of land
- -age of invertabrates and amphibians
- -ends in Permian extinction (96% marine animals died)
- Mesozoic era: 241-65 million yrs ago
- -3rd longest ~186 million yrs
- -age of dinosaurs
- -flowering plants appear near the end
- -ends in Cretaceous extinction, which opened the
- way for mammals to diversify
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- Cenozoic era: 65 million yrs ago to present
- -shortest
- -age of mammals
- -origin of man
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Why are plate tectonics important in understanding the distribution of species on Earth?
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What are mass extinctions? Why are they often followed by
adaptive radiation?
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Linnaeus’ system for naming organisms: binomial
Binomial:
-italicized
-genus capitalized, species not
0must be unique for each species
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Taxonomic hierarchies, and their relationship to one another
(nested system from Domain to species).
Species in genus are more closely related thatthose in the same class
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Relatedness based on DNA sequences or proteins
- -traits must be homologous (from common
- ancestor), not analogous
- -molecular systematics use DNA or RNA or amino
- acids sequences to determine relationships among organisms
- 0the more recently two species their nucleotides
- and amino acids sequence should be
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Basis of cladistic analysis- what is parsimony, and how do you use it to make decisions about common ancestors?
- Cladistics: groups of organisms by common
- ancestory
- Clade: ancestral species and all its evolutionary
- descendents
- -to identify clades, scientists compare an
- ingroup with and outgroup (which tells them what the ancestors looked like)
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Potential exam question: Provide and explain two reasons why scientists need more than one species concept.
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