U3: C16: Evolution Flashcards
Gene pool
total of all alleles in a population
evolution
change in gene pool, via (natural selection, mutation, genetic drift, genetic shift)
Theories of evolution x 4
- Lamarcks: inheritance of acquired characteristics
- Darwin: natural selection
- Neodarwin
- Punctuated equilibrium
Inheritance of acquired characteristics
- is a theory of evolution, by Lamarcks.
- it believed that used traits evolved, and unused traits -atrophied.
- this theory is wrong, traits are inherited not acquired
Darwin’s natural selection
beliefs
is a theory of evolution
- few offspring survive and reproduce
- chance variations due to mutation or recombination, that increase fitness (success for reproduction), will be selected for
- survival of the fitness leads to increase of those favorable genes in gene pool
- adaptation to environment cause organisms to separate into different species
- macroevolution, takes long period of time, and stable
Neodarwinism
is a theory of evolution
- that modifies natural selection so that not all traits had to be selected for, instead occur by gene population trends
Punctuated equilibrium
is a theory of evolution
- evolution occurs in rapid bursts rather then gradually over time (ex: dinosaurs and mammals)
Homologous structures
share common evolutionary origin and similar in structure, but may appear completely different. (ex: bat wings and mammalian arms)
Analogous structures
different evolutionary origin but structure serves same function (dolphin fins and shark fins)
Vestigial structures
remnant of organs that have lost ancestral function
Hardy Weinberg Equilibrium
1. predicts
2. formula
(key pt)
- phenotypicf allelic frequencies in a nonevolving population
- p + q = 1, p^2 + 2pq + q^2 = 1 (p = dominant, q = recessive) (pq = heterozygous)
- there is 2x as many genes as individuals in a population bc each individual has 2 autosomal copies of each gene.
5 criteria of Hardy Weinberg Equilibrium
- large population size
- no mutations that affect the gene pool
- mating is random
- no net migration of individuals into our out of a population
- genes in a population are all equally successful at reproducing (no natural selection)
There is only brown and blue eyes in the population. If blue eyes is recessive and 36% of the population has blue eyes, find the pheonotypic frequency and gene frequency.
36% q^2 therefore q = .6
* q + p = 1, therefore p = .4
1. qq (blue eyes) = 36%
pp (brown eyes) = 16%
pq (heterozygous) = 2pq = 48%
2. 36% bb = 36% b allele, and 0% B allele
16 % BB = 0 % b allele, and 16% B allele
48% bB = 24% b allele, and 24% B allele
therefore 60% b allele, and 40% B allele
Microevolution
violates the (Hardy Weinberg)
- GENETIC DRIFT: random change in gene pool due to chance, it is more pronounced in small populations also referred to as founder effect, results from natural barriers or catastrophic events. (large population size)
- mutation (no mutations that affect the gene pool)
- assortive mating (mating is random)
- GENE FLOW: migration of individuals leading to loss or gain of genes, therefore changing the populations gene pool. (no net migration of individuals into our out of a population)
- natural selection (genes in a population are all equally successful at reproducing)
Natural Selection Modes
change in population over long period of times (1000s-1 million years)
- Stabilization: elimination of extremes
- Directional: adaptive pressure lead to emergence of dominance of an initially extreme phenotype
- Disruptive: both extremes selected for over the norm.
- Group: natural selection acting on the group not the individual, explains altruism
Altriuism
sacrifice the fitness of individual to beneift the group (family), which have similar genes with the individual. When the benefit outweighs the cost, this behavior is selected for.
fitness vs inclusive fitness
- ability to pass your genes, or reproduce
2. # of alleles passes on to the next generation, even if only indirectly through altruistic behavior.
In order to be the same species it must meet 3 criteria
- interbreed
- produce fertile, viable offspring
- do this randomly
bottleneck
severe reduction i population size (from catastrophes)
genetic drift
random changes in allele freq (effect of genetic drift increases as population size decreases)
Speciation
different species, bc reproductive isolation
- prezygotic (no zygote formation)
- postzygotic (zygote can’t form viable offspring)
Name the evolution patterns
what causes similarities bw 2 species
- divergent
- parallel
- convergent
divergent evolution
same lineage, evolving apart to be more different
-produces homologous structures (bat wings and horse hoofs)
parallel evolution
same lineage, evolving closer together to be similar, using similar mechanisms/ mutations
convergent evolution
different lineage, evolving closer together to be similar, using different mechanisms
-produce analogous structures (bat wings and butterfly wings)
K selection
Natural selection, Fitness
- producing few number of offspring that mature slowly with lots of parental care
- sigmodial growth curve, carrying capacity (max number of organisms that an environment can maintain) level off
R selection
Natural selection, Fitness
- producing large number of offspring that mature rapidly with little parenting care. High brood mortality rate
- population growth curve are exponential, generally found in unpredictable, rapidly chancing environment.
Origin of life Development 1. organic molecules 2. RNA 3. protocells 4. prokaryotes 5. eukaryotes
- organic molecules created by atm gases zapped by lightning, which falls into the ocean to make primordial soup. Miller’s experiment proved this in the lab
- RNA world hypothesis: simple organic molecules formed RNA polymers that can self replicate (having enzymatic activity as well as serving as a template)
- Protocells: aggregates of RNA, proteins inside lipid envelopes
- Prokaryotes: first anaerobic heterotrophs bc early atm blocks the light req for photosynthesis, then anaerobic autotrophs that undergoes photosynthesis and makes oxygen, the aerobics that utilize oxygen.
- Eukaryotas: evolved by endosymbiosis, where a big cell engulfed a smaller cell and then developed a mutualistic relationship. Hetertrophs engulfed mitochondria, autotrophs engulfed chloroplast.
