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| it is the change in the allele (trait) frequency within a population overtime. In other terms, it is the change in how often a genotype/ phenotype occurs in a population over time. |
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| is a group of interbreeding species living in the same area. This group is always made of individuals of the same species that have their own alleles. Reproduction in the group of individuals allows for mixing of genes (increasing genetic diversity) |
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| is the study of changes in allele frequencies of a population, or the study of evolution. |
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| is all of the alleles (genes) of a population. Like the genes found in the population of a farmers heard of cattle. |
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| exists when the characteristics of one individual differs from the typical characteristics of the species (we call this variety) Variation can be caused by many things, including: mutations, sexual reproduction, exprosure to carcinogens (causing mutations), crossing over, migration of individuals into or out of the population, or even genetic drift (random chance). it is the variation in genes that makes sexually reproducing organisms "better" than asexually reproducing organisms. |
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| is very important term in describing evolution. it refers to any characteristic OR behavior that improves the chances of survival for an organism. BUT, individuals are BORN WITH the genes for their adaptations, they do not"develop" these adaptations over a life time (unless their genes are mutated by something in their enviroment). Thus, adaptations are caused by the natural genetic variation in populations- which enables some individuals in the population to be better able to survive. unfortunatly, non-scientists and some scientists too, inappropriately use the description, "adapt tp" when describing organisms behaviors or characteristics. |
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| is an adaptation that results when the coloring/ shape of the organism enables it to blend into its enviroment |
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| is another adaptation that results when the color of an organisms reminds/ warns the other that they are not good to et of that they are deadly/harmful if eaten. Poison dart frogs are one of the more well -known species that rely on warning coloration to avoid being eaten. as a result, they have no need to use energy to hide from their predators. |
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| is another adaptation that results when one organism that is NOT poisonous/ dangerous- resembles another organism that has warning coloration or some kind of protection. this organism relies on predators "knowing" to avoid the warning coloration/ shape. |
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| is a change in genes (it can be good or bad) |
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| is a change in genes (trait or behavior) that ALWAYS improves an organisms chance of survival (always good) |
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| Lamarke's theory of acquired characteristics |
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| this explanation is for how evolution occurs states that individuals acquire characteristics because of their environment and transmit them to their offspring. |
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| is a mechanism (explanation for how it occurs) of evolution. it explains that evolution occurs in populations because of adaptations of individuals based on the genetic diversity in a population. |
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| bacteria populations have natural genetic variation. when you get a bacterial infection, the population that infects you will have variation eve though they do not do sexual reproduction. you take an antibiotic prescribed by your doctor to kill bacteria causing the infection (killing them should eliminate the symptoms you feel because the bacteria are reproducing out of control and your body is trying desperately to fight them. the antibiotic will kill MOST of the bacteria but because of genetic variation, some already have an adaptation/ mutation that allows them to survive and reproduce without being affected by the antibiotic. The surviving bacteria reproduce and you get the infection again. So, with the infection again, you return to the doctor and he/ she may prescribe the same antibiotic. you follow the instructions for taking this antibiotic but you dont get better. this happens because the bacteria that have reproduced, causing this second round of the infection, had an adaptation (resulting from natural genetic variation) that let them be resistant to this antibiotic which is why they survived. and the population has evolved! in order to fight this infection you will need to take a different antibiotic (one that is able to kill this evolved population.) |
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| the evolutionary example of insects going through natural selection as a result of pesticide exposure works the same way as as just described for bacteria and antibiotics: there is genetic variation in the population, so that some individual insects have genes that make them better able to survive exposure to the pesticides (resistant to the pesticides), they survive and reproduce so that the next generation will have mostly individuals with this resistance (the population has evolved and the pesticide is no longer effective in killing them). |
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| exists in the historical record of populations left in bones and shells (fossils). unfortunately, not all once living species have been fossilized (the organism has to die in a very specific way- usually near or in water so that sediments can be placed on top of it turning it to stone using minerals and pressure. Also, only bones and hard shells can become fosssils, soft body tissue does not fossilize. However, soft tissues can leave imprints in the mud or become frozen enabling us to study such extinct species. |
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| an embryo is the early development of an organism (in humans from about week 1 after fertilization through about 8 weeks) all organisms go through some kind of embryo like development. |
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| when different organisms have the SAME STRUCTURE but with a different function, these structures are called homologous structures. for example, vertebrate forelimbs ar all made of the same bones but some are used for walking, some for swimming, some for flying... |
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| describes how different species as different as whales and bats must have had a common ancestor ir oder for them to have similar bone structure. |
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| when organisms have a structure that no longer serves a a function, in the organism but it did have or must have had a function for its ancestors that structure is vestigial. for example, the human appendix, the eyes of naked mole rats, who live their entire life underground and the pelvis of whales. |
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| reproduction isolation is occurring if a population loses the ability to reproduce with some of its members, and as a result, goes through evolution. for example, some individuals in a population can have a different mating behavior than others. |
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| a mutation that results from nondisjunction during meiosis. |
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| a pattern of evolution that occurs when a population enters a new environment and individuals in the population encounter competition for resources. in this new environment, some individuals will have genes that enable them to better compete/ survive and reproduce. |
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| Stasis (another pattern of evolution) |
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| this pattern of evolution occurs when a population has adaptations that are very well suited for its environment AND it's environment hasn't changed much over time, so there has been little "pressure" to change the gene pool. |
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is a pattern of evolution that results when unrelated species evolve similar traits even though they live in different parts of the world. this happens because the geographically isolated areas have similar ecology and climate, this, similar ecological
"pressures" on the individuals, so over time, the populations may begin to appear similar. |
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| occurs when there is a short period of rapid change just after a population becomes isolated and after that period of rapid change, the population then changes very slowly. this pattern would explain why there would be missing gaps in the fossil records. |
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| is a type of natural selection that occurs when an extreme phenotype is flavored (they survive best) as an adaptation allowing organisms with this phenotype to survive better and reproduce so in future generations the number of individuals with that extreme phenotype increases. we have already discussed some of the best examples of directional selection including giraffes- long necks. |
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| occurs when the average phenotype is favored as an adaption allowing organisms with this phenotype to survive better and reproduce so in future generations the number of individuals with the average phenotype increases. there arent as many good examples of this type of selection but the size of human infants is an example because smaller infants and larger infants died and over time an average infant size has survived. |
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| occurs when two extreme phenotypes are favored (they survived best) as an adaptation allowing organism with these extreme phenotypes to survive better and reproduce so in future generations the number of individuals with the 2 extreme phenotypes increases and the average decreases. |
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| this type of selection was originally described by charles darwin, it occurs in populations where males and females differ significantly in appearance. usually it is the male of the species that brightly colored and the female is dull colored to protect the eggs/ offspring at the nest. |
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