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Evolution

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August Weismann
chopped tails off of mice, bred together. All 22 generations of offspring had tails
Artificial classification groups made by humans
Domain, Kingdom, Phylum, Class, Order, Family, Genus
Bottleneck Effect (genetic drift)
environmental "disaster" dramatically reduces population size (random); survivors repopulation and allele frequencies differ from original poulation
gene pool
all of the available alleles (and genes) in a population
Behavioral Isolation
mating behaviors and courtship rituals keep different species distinct (Assortative mating- like mates with like- only within same population (species))
monophyletic group
one related group within same cladogram (all same ancestral line)
Creationism
a creator made/designed all organisms as is (no changing of species over time)
Relative Dating
undisturbed fossils in sedimentary rock layers (deeper- older/simpler; upper layers- newer/more complex)
Use and Disuse
body parts/structures that are needed or used become more developed over time, while those not used are less developed and will eventually disappear
Disruptive selection
eliminates intermediate phenotypes; selectes for "extremes" to reduce competition
How is fitness measured?
By number of offspring
Jean Baptiste Lamarck
first to explain how/why species change over time
systematics
doesn't consider evolutionary ancestry- uses "checklist" method- compares number of similarities; more check marks in common- more common groups; produces phylogenic tree
Thomas Malthus
Essay on Principles of Population- resources will determine how big a population gets
Theoplorastus
student of Aristotle- classifies plans and stem structure (herbaceous-herb: soft green and juicy stem; one thick stem- trunk-tree; many woody stems- shrub- bush)
overproduction
a popluation produces more offspring than the environment can support
not "good" species
if they can mate successfully with each other and produce reproductively able offspring (gene flow between neighboring populations esablishes SUBSPECIES)
Selection
some member selected for; others against (predators, climate conditions, antibiotic resistance, pesticide resistance)
cladistics
produces clade; classification using evolution; tries to establish an order on clade of how orgnisms develop over time
hybrid breakdown
offspring dont' survive to adulthood
competition
the entire population competes for the same limited resources
Adaptive radiation
founding population occupies an island, groups with different variations spread out (radiate) and occupy enviornments to which they are best adapt
Non-random mating (Assortive)
choosing a mate based on a characteristic; may be based on sexual selection (sexual dimorphism- males and females look different)
Comparative embryology
look at embryological development between species- compare/contrast (lots of similarities- common ancestor)
Natural Selection
Overproduction, Competition, Variation, Survival of the Fittest, Speciation
taxonomy
classifying and naming organisms
sympatric species
groups of different species that live in the same geographic region
hybrid sterility
offspring don't make gametes (meiosis errors)
Mechanical isolation
male and female reproductive organs don't fit together
Genetic drift
changes in size of population from large to small; new allele frequencies differ from original population
Species
can reproduce with each other and make viable offspring that can also reproduce- only naturally existing classification group
Prezygotic Isolating
mechanisms that prevent a zygote (fertilization) from forming
Aristotle
first to classify; based on habitat (land dwellers, sea dwellers, air dwellers)
Alfred Russell Wallace
independently came to same conclusions as Darwin about evolution (natural selection)
Modern Synthesis Theory
combination of Darwin and Mendel's ideas: beak shape/size and feather colors among Darwin's finches povide evidence for evolution
Fossil Record
compare remains of organisms that were once alive to ones that are alive today (look at structural (anatomical) characteristics)
Absolute dating
use radioactive isotopes (carbon has half-life of 5,760)
Industrial Melanism
The frequency of dark (melanistic) and light (amelanistic) peppered moths correlates with the level of pollution in the environment
Homologous structures
structures that are "built similar" and formed the same way during development but have slightly different functions. Point to common ancestor (divergent evolution)
Gene Flow
new genes entering; if favorable then their frequency increases
artificial selection
animal/plant breeder chooses desirable traits and breeds organisms together to get the desired trait
How can natural selection maintain variation?
Can maintain color variations based on environment and predation; Heterozygote advantage (ex: sickle cell anemia nad malaria
Post- Zygotic
fertilizaiton happens but:
Hardy-Weinberg
large population, random mating, no immigration or emigration (gene flow), no mutation, no selection
speciation
overtime the population may change enough so that a new species forms
variation
no all members are identical; some variations give survival advantage: ADAPTATIONS- traits that have survival advantage
Charles Lyell
Principles on Geology- the earth is a very old planet that is constantly changing; slowly- gradualism
cladograms
start with an outgroup- organism that is least related; establishes order of evolution by development of new (derived) characteristics; ends with organism being studied
Ecological isolation
species live in same ecosystem, but distinct niche (dont' overlap so don't interbreed)
Embryo breakdown
doesn't develop properly
mutation
permanent change in DNA- favorable mutation (adaptive value)- its frequency will increase; if mutation is not favorable it may be eliminated
Vestigial Structures
used to have a function, but not any more
Geographic Isolation
species or populations become separated by a geographic barrer; prevents gene flow between groups (and if long enough- two groups may become different species)
Inheritance of Acquired Characteristics
newly acquired traits are passed to offspring
Stabilizing selection
intermediate (average) phenotype is most adaptive and is selected for
survival of the fittest
organisms with the adaptations for their environment are most fit and are selected for. Organisms without these adaptations are selected against and may die (their traits are removed from the population)
Temporal isolation
separated by time (seasons); breeding seasons don't overlap and so don't encounter one another when they reproduce
population not individual changes over time
natural seleciton directly works on the phenotype and indirectly works on the genotype
Directional selection
a specific trait (phenotype) is the most adaptive and is selected for over all others
polyphyletic group
organisms that developed similarly due to convergent evolution (not related points of divergence)- adaptations; derived characteristics
Linnaeus
classifies by structure; picks Latin; uses scientific names Genus species
Founder Effect (genetic drift)
happens when species populate an island; new allele frequencies don't represent original population
allopatric speciation
geographic isolation isolates gene pools, each gene pool is affected by a different environment and different selection mechanisms
Prevention of gamete fusion
cell surface proteins prevent fertilization
Analogous structures
built totally differently but have same function- ocnvergent evolution (environment determined best adaptations)

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