Term
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Definition
| Incorrect form of evolution. From Jean-Baptiste Lamarck. Suggested that acquired characteristics were passed on to offspring (Ex. a giraffe's neck got longer by stretching to reach leaves. It's offspring acquired these traits). Genetics does not work this way. |
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Definition
| Naturalist on the HMS Beagle. Their voyage lasted 5 years with the mission of mapping S. American coast. Darwin collected plants and animals and was deeply affected by the diversity he encountered. When the voyage was over he sought an explanation for the origin of species. His enduring idea is summarized in Darwin's Postulates. |
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Term
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Definition
1. (This one came from Thomas Malthus) The ability of a population to expand is infinite, but the ability of the environment to support populations is finite.
2. Organisms within populations vary, and this variation affects the ability of organisms to survive and reproduce.
3. Variations are transmitted from parents to offspring. |
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Term
| Birds of the Galapagos (results of study) |
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Definition
| The finches of the Galapagos islands show us how natural selection works. In the 70s there was a sever drought on the islands. This affected seed availability, and many birds died of starvation. During drought, larger beaked birds were at an advantage because small beaked birds have trouble with large seeds.As a result, the mean beak size in the population increased. However, natural selection can produce change or maintain status quo. Large beaked birds have a higher juvenile mortality, and so selection favored an intermediate size beak. |
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Term
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Definition
| A state in which natural selection will maintain stasis (no change). |
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Term
| Types of natural selection |
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Definition
Directional selection: shifts the frequency towards a particular characteristic.
Stabilizing selection: when selection prefers an intermediate quality, increasing the frequency at the intermediate phenotype. |
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Term
| Who does selection act upon? |
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Definition
| Selection acts upon individuals that are competing with other individuals within populations (that means two members of the SAME population compete with each other. |
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Term
| What two things are individuals competing for? |
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Definition
| Survival and reproductive success. |
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Term
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Definition
| It is contextual. It is in comparison to others in the group. It can happen at a specific place and time. There is no end goal/optimal form. It can be having more offspring now, or surviving until reproduction is possible. |
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Term
| Selection maximizes whose fitness? |
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Definition
| It maximizes individual fitness, not group fitness. |
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Term
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Definition
| Was used to argue for group selection over individual selection. An example of reproductive restraint was seen in birds: they did not lay as many eggs as they could, as too many birds would equal starvation for the group, argued Wynne-Edwards. |
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Term
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Definition
| Lack's response to reproductive restraint, said that when there are too many nestlings, they all risk starvation. Thus the optimal clutch size is selected for. |
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Term
| How does natural selection produce complex changes? |
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Definition
| Natural selection allows for the cumulative retention of small changes.Complex adaptations arise through many small steps, with each being favored by selection (example: eye) |
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Term
| Examples of rapid evolution |
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Definition
| Domestication of dogs produced the variety of dog breeds that we now know in the last few thousand years. Radiation of Galapagos finches happened over the course of 500,000 years. |
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Definition
| Fleeming Jenkin asked how variation is maintained, and where novel variations come from. The problem was that Darwin did not know the mechanics of inheritance. |
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Term
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Definition
| Conducted experiments on the inheritance of peas. Showed how inheritance was not about blending. |
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Term
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Definition
| A segment of chromosomal material that produces a recognizable effect on phenotype and segregates as a unit during gamete formation |
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Term
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Definition
| One of two alternative forms of a gene |
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Term
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Definition
| Results in the same phenotype in heterozygous and homozygous forms |
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Term
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Definition
| Expressed in the phenotype only under homozygous conditions |
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Term
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Definition
| Are defined by a single pair of alleles. |
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Term
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Definition
| The combination of alleles that characterizes an individual at the same set of genetic loci |
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Term
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Definition
| The observable characteristics of an individual. Individuals with the same phenotype can have different genotypes. |
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Term
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Definition
| a cell which forms the body; any cell which is not a gamete |
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Term
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Definition
| a sex cell, such as a sperm or egg |
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Term
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Definition
| describes cells that have pairs of each chromosome. Somatic cells are diploid |
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Term
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Definition
| a cell that only has one copy of a chromosome. Sex cells are haploid |
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Term
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Definition
| pairs of chromosomes. Are only in diploid cells |
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Term
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Definition
| the process of division of somatic cells, producing new diploid cells |
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Term
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Definition
| the process of cell division which produces haploid gametes |
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Term
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Definition
| a fertilized ovum (egg). It is formed by the fusion of gametes. When gametes fuse, they create a cell with a full set of chromosomes, rather than only 1 copy. |
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Term
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Definition
| a portion of the cell which contains chromosomes. |
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Term
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Definition
| the original parents, initial generation |
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Term
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Definition
| offspring of original parents |
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Term
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Definition
| the generation of which F1 are the parents |
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Term
| How is variation maintained? |
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Definition
| Variation is hidden as recessive alleles in heterozygous individuals. Selection acts on the phenotype, but heterozygous individuals also carry the allele that codes for an alternative phenotype. |
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Term
| What traits are allowed to segregate independently? (that is, they are not inherited together) |
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Definition
| Only traits which are on different chromosomes can segregate independently (with the exception of crossing-over) |
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Term
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Definition
| Particular site on a chromosome where a gene is located. Loci are lined up like beads on a string. Genes on the same chromosome tend to stay together. |
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Term
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Definition
| the tendency for genes on the same chromosome to stay together |
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Term
| Crossing over/recombination |
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Definition
| Bits of one chromosome can be swapped between members of a homologous pair when chromosomes tangle and break during meiosis. The closer two loci are, the more likely they are to stay together. |
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Term
| When can crossing over occur? |
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Definition
| This can only occur during meiosis. |
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Term
| Which evolves faster, asexual or sexual species? |
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Definition
| Sexual species, as they can have a novel combination of traits that is different than either parent. |
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Term
| What are genes composed of? |
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Definition
| Genes are composed of DNA. |
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Term
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Definition
| double helix of sugar-phosphates joined by sequences of bases: adenine thymine guanine cytosine. Vast number or sequences with the same stability. |
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Term
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Definition
| Genes (composed of DNA) code for proteins. Proteins are manufactured in cells, and genes instruct how they are built. Some genes have more than instructions for building proteins, they also have regulatory functions for when, where, and which proteins should be manufactured (regulatory functions) |
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Term
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Definition
| The proportion of a particular gene in a population |
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Term
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Definition
Only holds when all genotypes equally likely to produce gametes.
p2 +2pq +q2 = 1
where p and q are allele frequencies
and p2 and 2pq and q2 are genotype frequencies |
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Term
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Definition
Examples: height and weight
Affected by genes at many loci, each locus has a small effect on phenotype |
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Term
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Definition
Examples: finger number and tongue rolling
affected by genes at a single loci |
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Term
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Definition
| Arise spontaneously, are "mistakes" made in DNA replication. Most are fatal, but some can be neutral. Very few lead to DNA changes that can be adaptive. |
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Term
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Definition
| section of DNA skipped during replication |
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Term
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Definition
| sections of DNA replicated at least twice |
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Term
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Definition
| sections of DNA replicated in the wrong order |
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Term
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Definition
| chromosomes read in incorrect order |
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Term
| Explanation of chihuahuas from wolves |
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Definition
| Size of wolves dictated by continuous traits, large wolves have much more + alleles for size, and few - alleles. As they are selected against though (in the case of dogs, by breeding) - traits become much more prominent. Hidden variation explains the chihuahua problem. |
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Term
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Definition
| Occurs for continuous traits. When the effect of each locus is small, environmental variation will blur genetic differences. New combinations with more - alleles will be outside initial range of variation. |
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Term
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Definition
| Domestication, can select for small dogs or big poultry |
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Term
| How is variation maintained? |
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Definition
| It is often hidden and protected. Even when selection is strong, there are loci (sometimes more than one per trait) which remain in the population, but are not allowed to produce phenotypic differences. Mutation also introduces variation at low rates. |
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Term
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Definition
Recombination/crossing-over
Mutation (at low rates)
Reshuffling of multi-locus gene combinations |
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Term
| Selection of flexible behavior |
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Definition
| Selection can produce behaviors which vary under different situations. For example the soapberry bug has different mating strategies depending on cost/benefit ratio. This flexible strategy is selected for when there are variable conditions, however, it is selected against when the flexible strategy leads individuals to make mistakes. |
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Term
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Definition
| Arise when the same genes affect multiple traits. This means that when selection acts on one trait, it affects other correlated traits. This means that selection can also create MALADAPTIONS |
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Term
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Definition
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Term
| When does natural selection produce optimal adaptations? |
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Definition
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Term
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Definition
| The state in which equilibrium is not yet achieved, and so adaptations will be selected for or against. |
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Term
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Definition
| The randomness of selection. Has greatest affect on small populations (think statistics! You want a larger sample size for normal distribution). Also known as Founder effect. |
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Term
| Local vs. Optimal adaptations |
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Definition
| Some adaptations look poorer than others, for example, compound eyes which are not as effective as lens eyes. Remember cumulative retention, selection changes existing traits. |
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Term
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Definition
| Has to do with optimal vs. local adaptation. Natural selection is like a climber with the rule "always go up." In some cases this works out and produces the best outcome. Other times you go so far up a path but don't reach an ideal solution, if you could go evolutionarily backwards, you would change directions somewhere before continuing up. However, you can't go backwards evolutionarily. A species may produce a local optimum, but not the global optimum. |
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Term
| Physical and chemical limitations on adapatation |
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Definition
| Heavy animals need strong bones, but strong bones are heavy. Thus there are no heavy flying animals. Similarly, male mammals do not lactate because the hormones that facilitate milk production inhibit testosterone production. |
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Term
| Are populations and species fixed or dynamic? |
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Definition
| Populations and species are dynamic, not fixed types. Intermediates can breed with neighboring intermediates, but separate intermediates cannot interbreed. |
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Term
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Definition
| Movement of genes from one population to another, in or out |
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Term
| Biological species concept (and problems) |
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Definition
Reproductive isolation maintains boundaries. Gene flow causes species to adapt as a unit. Without gene flow, species diverge and adapt to their own habitat.
Problem 1: Gene flow can occur between "good" species. Medium finches mate with large ground finches, why aren't they one species?
Problem 2: Species remain homogeneous without gene flow, some don't mix, but don't diverge either. |
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Term
| Ecological species concept |
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Definition
| Natural selection maintains species. Selection favors certain phenotypes. Hybrids do poorly (small population of hybrids do not grow). Selection maintains differences between species |
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Term
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Definition
| External barrier, reproductive isolation |
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Term
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Definition
| partial isolation, selection leads to speciation |
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Term
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Definition
| no isolation, selection leads to speciation. There needs to be variation and an OPEN NICHE |
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Term
| How speciation types relate to biological vs. ecological species concept |
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Definition
Allo = biological
Para = intermediate (though Snyder says ecological)
Sym = ecological |
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Term
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Definition
| A factor that leads to hybrids doing poorly. Hybrids are not preferred as mates (sexual isolation) |
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Term
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Definition
| Hybrids have more competition in the ecological niche. Hybrids are displaced and don't necessarily fit a particular niche or space. |
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Term
| How character displacement reinforces species boundaries. |
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Definition
| When species coexist, intermediate individuals face more competition. Selection exaggerates differences between species, as seen with Darwin's finches. |
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Term
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Definition
| The science of classifying organisms into different categories. Heirarchical structure reflects real relatedness between organisms. Phylogenetic tree is a hypothetical hierarchy of evolutionary relationships |
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Term
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Definition
| the evolutionary history of a population of taxon |
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Term
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Definition
| a theory of classification that differentiates between shared ancestral and shared derived traits. Concerned with the order of branching phylogenetic lineages |
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Definition
| A group of species with a common evolutionary ancestry |
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Term
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Definition
| Ancestral traits, similarities due to inheritance from a common ancestor |
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Term
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Definition
| structures that are superficially similar and serve similar functions bet have no common evolutionary relationship. The result of convergent evolution |
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Term
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Definition
| Nonhomologous similarities in different evolutionary lines |
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Term
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Definition
| appeared recently in homology and is shared by a relatively small group of closely related taxa |
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Term
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Definition
| a trait which did not appear as recently as derived features and so is evident in a larger number of species. |
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Term
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Definition
| phylogenetic diagrams based on shared characteristics and includes visual depictions of time. |
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Term
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Definition
| an error in reasoning that assumes that the way things are is the way they are meant to be, and that natural is automatically good. |
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Term
| Why study primates? Homology reason |
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Definition
| We evolved from something like modern apes. Understanding modern apes will allow us to understand our ancestors |
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Term
| Why study primates? Analogy reason |
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Definition
| We're similar to other primates in terms of morphology, physiology, and behavior |
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Term
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Definition
FEATURES OF HANDS & FEET
Opposable big toe
grasping hands
sensitive finger tips
flat nails
FEATURES OF SENSORY ORGANS
highly developed sense of vision
eyes moved forward in head
stereoscopic vision
unspecialized olfactory senses
FEATURES OF LIFE HISTORY
small litters
long pregnancy
long juvenile period
long mother infant bond
long life span
LARGE BRAIN
LIVE IN GROUPS |
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Term
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Definition
One major division of primates:
Have snout & rhinarium
more acute sense of smell (also known as prosimians) |
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Term
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Definition
Flatter noses without rhinarium
less reliance on smell
generally corresponds to anthropoids |
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Term
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Definition
Prosimians, but haplorrhini
they are taxonomic outliers |
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Term
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Definition
PROSIMIANS (STREPSORRHINE, exception: tarsiers)
- lemurs
- lorises
ANTHROPOIDS (HAPLORRHINES)
-New world monkeys
-old world monkeys
-Apes
----Lesser apes
----Great apes |
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Term
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Definition
| an organisms size, shape, and composition |
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Term
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Definition
| The process by which an equilibrium state is produced |
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Term
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Definition
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Term
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Definition
| the ability to produce offspring |
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Term
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Definition
| all the genes carried on all the chromosomes |
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Term
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Definition
| genes on different chromosomes |
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Term
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Definition
| specify structure of proteins |
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Term
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Definition
| determines the conditions under which the message encoded in a protein coding gene will be expressed |
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Term
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Definition
| three letter "words" of base combinaitions which specify a particular amino acid |
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Term
| Process of translating DNA to proteins |
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Definition
DNA -> mRNA -> ribosome
ribosome reads from mRNA and takes material from tRNA to build a protein |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| the reconciliation of darwin and Mendel, explaining how variation can be maintained with selection and how inheritance occurs |
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Definition
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Term
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Definition
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Term
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Definition
| when one allele is lost in a population, making all members identical at that particular locus. |
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Term
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Definition
| when a population diversifies to fill many niches |
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Term
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Definition
| actively defending territory from members of own species |
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Term
| Assumptions of Hardy weinberg |
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Definition
random mating
no gene flow/no immigration
no genetic drift/infinite population
no mutations
natural selection is not acting |
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