Evolution
Terms
undefined, object
copy deck
- 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)