Biology Evolution

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Spontaneous Generation/Abiogenesis

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the idea that life can arise from nonlife

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Biogenesis

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idea that life can only arise from previous life (proved by Redi and Peasteur with the curved flask)

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Arachaebacteria

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The first cells, didn't need oxygen or sunlight (chemosynthesizing)

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Cyanobacteria

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The first photosynthetic organisms. They put an abundance of oxygen in the atmosphere.

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Endosymbiosis

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The process of how eukaryotes evolved. Mitochondrion and chloroplasts both had DNA and ribosomes which meant they were seperate prokaryotic cells that lived in close relation which eventually became one cell.

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Fossils

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The preserved evidence of a living organism. Only occured if the organism was buried quickly before decomposition and in sedimentary rock. (paleontology) Can be found in amber, sediments, or ice. Significance: previous life is different, morphological changes, environmental changes

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Relative dating

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comparing layers of fossils: deeper the older unless disturbed

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Radio Metric Dating

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Using decay of radioactive isotopes to measure age (half life of an isotope)

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Homologous Structures

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anatomically similar structures. Singificance: appear to be inherited from a common ancestor

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Analogous Structures

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structures among different organisms that have the same function but different structure. Significance: similar environments promote similar adaptations but not from common ancestry

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Vestigial structures

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structures that are reduced forms of functional structures in other organisms. Significance: perhaps used in previous generation

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Natural Selection

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The environment selects favorable traits in organisms over time. Darwin's theory of Evolution (survival of the fittest) Consists of 4 basic principles.

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Variation

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Individuals in a population differ from one another
example: beetle could be green or brown

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Heritability

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variations are in herited from parents because some traits are not inherited example: diet differences

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Overproduction

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populations produce more offspring than can survive example: not all beetles can grow to maturity

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reproductive advantage

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some variations prove to be more successful than others

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Fitness

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An organism's ability to survive

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Adaptation

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Traits that increase an organism's fitness

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Hardy-Winberg Equilibrium

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a mathemtical equation that assumes a species is not evolving (shows if it is at an equilibrium)

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Allopatric speciation

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a physical barrier separates 1 population into 2 or more

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Sympatric barrier

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speciation occurs without a physical barrier

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Mimicry

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ability to mimic another organism's image

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Camouflage

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ability to blend into surroundings

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Stabilizing selection

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When selective pressured select against the two extremes and for the average.

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Disruptive selection

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When selection pressured act against individuals in the middle of the trait distribution

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Directional selection

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One extreme of the trait distribution experiences selection against it.

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Gene pool

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entire collection of genes among a population

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Allelic frequency

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percentage of a particular allele in a gene

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Genetic equilibrium

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a population in which the frequency of alleles does not change from generation to generation (changes in genetic equilibrium lead to evolution or speciation)

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Speciation

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evolution of a new species, starts with a barrier which leads to reproductive isolation

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gradualism

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idea that species originate through a gradual buildup of adaptations

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Punctuated equilibrium

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when speciation occurs quickly in rapid bursts, with long periods of stability inbetween

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Convergent evolution

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distantly related organisms evolve similar traits because of similar environmental selection pressures

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Divergent evolution

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also called adaptive radiation, occurs when change from a common ancestor increases as time passes which leads to homologous/vestigial structures

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Artificial selection

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selection by humans, intentional breeding for specific traits

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Gene flow

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transfer of genes from one population to another

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Conditions for Hardy-Weinberg

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1. No mutations
2. No genetic drift
3. No gene flow
4. No natural selection
5. Random mating

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Genetic drift

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random change in allelic frequencies in a population (small)