Evolution

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for 50% of the radioactive material to decay Length of decay = = life duration • #of ¹/2 lives Scanned with CamScanner F 4 9 -Embryology comparison the similarities of embryos as they develop suggest common ancestry among different organisms -comparison of structures comparing the fassil structures of organisms. in very different parts of the world suggest a common ancestor analogous structures - body parts found in different organisms that are for the same function but are completely different in their evolutionary origins. homologous structures - body parts found in different but related organisms that are adapted for different functions. vestigial structures - have no direct function in modern species. but had a major function in ancestral species. -molecular similarities : compares the genetic (DNA) and the chemistry (protelns) of organisms. Natural Selection ↳ the process by which individuals with inherited characteristics well-suited to the environment leave more offspring than other individuals with Schrif less-suited characteristics. 1. every organism has the be potential to produce many offspring during its lifetime 2. individuals that have superior physical or behavional attributes are more likely to survive than individuals with inferior qualities. 3. by surviving, those species have the opportunity to reproduce and pass on their favorable characteristics. ↳as these characteristics increase in the population, the population will gradually change of over time.... natural selection depends on the environment; acts on existing heritable variation ↳ caused by random mutations. Scanned with CamScanner Variation and Patterns of Evolutione pres the raw material for natural selection; there have to be differences within a population → some individuals must be more fit than others. biological fitness - being able to survive + pass favorable traits to your offspring Where does variation come from? therefore change 1. mutation: random changes to DNA; changes in protein may change phenotype" 2. sexual reproduction: random combination of genes. Gene Flow ↳movement of individuals + alleles in and out of populations. -Seed + pallen distribution by wind and insects -migration of animals; causes genetic mixing across regions + reduces differences between populations. Genetic Drift ↳ the change in the frequency of a genetic variant by chance 1. Founder's Effect when a few individuals from a population colonize to a different isolated area. Their genes are then similar and each member of the colony has less variety pilate 2. Bottleneck Effect: when a large population is drastically reduced by a disaster, famine, natural disaster loss of habitat... Joss of variation by chance ↳population grows afterward with less variety Patterns of Evolution. 1. Divergent Evolution when one species evolves into two or more with clifferent characteristics; describes evolution towards clifferent traits in closely related species. adaptive radiation: one species gives rise to many different species in response to the creation of new environments. exs Scanned with CamScanner CO 12. .. Convergent evolution : unrelated species evolve similar traits even though they are not closely related; these traits have different origins. yet perform the same function ex: fins of a shark and fins of a dolphin 3. Coevolution : the mutual evolutionary influence between 2 species ↳when two species evolve in response to change in each other ↳ they are closely connected to one another by a syvebieticce 4. Gradualism: evolution proceeds in small gradual steps over a long period of time 5. Punctuated Equilibrium: stable periods of no interrupted by rapid evolution. Taxonomy classifying organisms bids Kingdom Phylum Pease Class come Order over Family For Genus Great Species Spaghetti • change (equilibrium) • makes up the scientific name; first word is genus, species, always lower case always capitalized, second is and onderlined/italicized Scanned with CamScanner