Evolution Exam Study Guide
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Charles Darwin
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Darwin saw that organisms produce more offspring than is required to replace themselves, so population sizes should increase rapidly (think about the number of frogspawn laid each year, or how many eggs a spider lays).
Darwin saw for himself, and confirmed his observation with others, that population numbers tend to stay at about the same level (you don’t see a doubling of the number of frogs or mice in your garden each year do you?)
Resources, such as food, water or places to sleep or mate, are limited. A major influence on
Darwin observing this fact was his reading the work of Thomas Malthus who published a paper stating that the human population was increasing at a rapid pace and would soon run out of food, water and space. These are three simple facts which Darwin put together to draw a simple conclusion: individuals compete with each other for scarce resources.
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Fitness
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In biology, an adaptation, also called an adaptive trait, is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection.
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They provide the variation in organisms that other recombination methods do not. A beneficial mutation, leading to a small change in same trait, that is even marginally reproductively successful to the organism that possesses it will be selected for and passed on thus changing the organisms population over time, regardless of how small the change. This is evolution, change in populations over time.
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Natural selection, a concept first theorized by Charles Darwin, is the adjustment of genes throughout generations based on factors that help it survive. Sometimes this is survival of the fittest or the organisms that are better suited to the environment in other ways.
Ex: In an ecosystem, some giraffes have long necks and others have short ones. If something caused low-lying shrubs to die out, the giraffes with short necks would not get enough food.
After a few generations, all the giraffes would have long necks.
Ex: Galapagos finches all have different types of beaks. During drought, the finches with the larger beaks survived better than those with smaller beaks. During rainy times, more small seeds were produced and the finches with smaller beaks fared better.
7. Carles Lyell (1797-1875), the famed Scottish geologist and paleontologist befriended the Charles
Darwin and strongly influenced his thought. In particular, Darwin's reading of Lyell's Principles of
Geology prompted him to think of evolution as a slow process in which small changes gradually accumulate over immense spans of time. In this founding document of modern geology, Lyell emphasized natural law. It makes sense, he said, to assume that geological processes acting in the past were much the same as those we see today — forces such as sedimentation in rivers, erosion by wind, or deposition of ash and lava by volcanic eruptions. This is the principle of uniformitarianism, the reasonable assumption that the forces that acted in the past are of the same sort as those we see acting today.

In emphasizing these natural processes, he undermined the claims of earlier geologists many of whom had a distinct tendency to explain geological formations in terms of biblical floods. In the same way, Darwin constructed an explanation of the origin of living things in terms of natural processes.
8. Catastrophism: Natural disasters such as floods and volcanic eruption shape landforms and cause species to either adapt or go extinct.
Gradualism: Slow changes effect landforms and land shapes forcing a species to slowly adapt.
Uniformitarianism: geological processes are the same throughout time. The same geological process are happening now that had happened millions of years ago.
9. Lamarck – theory of acquired characteristics (look it up  )
10. Variation is any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation). Variation may be shown in physical appearance, metabolism, fertility, mode of reproduction, behavior, learning and mental ability, and other obvious or measurable characters.
Ex: human height, Mendel’s pea plants, Galapagos finch beaks and tortoise shells
11. Low vegetation = longer neck; high vegetation = shorter neck
12. Evolution – change over time
13. Species - a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. (have to be able to breed together to be considered a species
Humans = Homo sapiens (Homo = genus; sapiens = species)
14. In biology, populations are groups of individuals belonging to the same species that live in the same region at the same time. Population density is a measure of the number of organisms that make up a population in a defined area.
15. Descent with modification is the term Darwin used for evolution. It explains both the unity of life and the diversity of life. The unity of life comes from descent; offspring resemble their parents, even over many generations. But organisms are not identical to their parents, they are also modified in the process; and this - over long periods of time - explains the diversity of life.
So for example, the homology between the forelimbs of a human, a bat, a porpoise, and a horse are explained by descent with modification. They have the same pattern of bones because all of those animals descended from a common ancestor, but the bones are not identical because they were modified for different functions -- grasping, flight, swimming, and running.
16. 1.) More individuals are produced each generation that can survive 2.)Phenotypic variation exists among individuals and the variation is heritable. 3.)Those individuals with heritable traits better suited to the environment will survive. 4.) When reproductive isolation occurs new species will form.

17. Farmers chose cattle with beneficial traits such as larger size or producing more milk, and made them breed; and although they may have known nothing about genes, they knew that the beneficial traits could be heritable. The farmers selected for certain traits in their cattle and probably noticed that the offspring were becoming more and more productive with each generation.
18. Don’t do
19. Darwin's Observations:
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There is a variation of characteristics/traits within a population
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Traits are passed from parent to offspring (heredity)
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Organisms produce more offspring that are able to survive (overproduction)
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Due to the lack of resources, some offspring may not survive
20. the branch of biology that deals with the geographical distribution of plants and animals.
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The study of one type of evidence of evolution is called embryology, the study of embryos. An embryo is an unborn (or unhatched) animal or human young in its earliest phases. Embryos of many different kinds of animals: mammals, birds, reptiles, fish, etc. look very similar and it is often difficult to tell them apart. Many traits of one type of animal appear in the embryo of another type of animal. For example, fish embryos and human embryos both have gill slits. In fish they develop into gills, but in humans they disappear before birth. This shows that the animals are similar and that they develop similarly, implying that they are related, have common ancestors and that they started out the same, gradually evolving different traits, but that the basic plan for a creature's beginning remains the same.
22 and 23. A common example of homologous structures in evolutionary biology are the wings of bats and the arms of primates. The opposite of homologous structures are analogous structures, which are similar structures between two taxa that were not present in the last common ancestor but rather, evolved separately.
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24. In humans the vermiform appendix is a vestigial structure; it has lost much of its ancestral function.
Vestigiality refers to genetically determined structures or attributes that have apparently lost most or
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all of their ancestral function in a given species, but have been retained through evolution.
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Ex: hipbone in whales and tailbone in humans

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25. Natural selection is the mechanism by which phenotypes and genotypes change for a population over many generations. In other words, it describes the underpinnings of evolution. The central precept of natural selection is that variation exists in a population and that because certain individuals (with certain traits) are better at staying alive, they have a better chance of surviving and are more efficient at passing on their genes.
Over the course of generations, natural selection can cause directional change in a trait, favor the extremes in a trait, or reduce variation in the population.
Natural Selection Operates on Phenotype
The traits that an individual expresses, its phenotype, are what will give that individual an advantage or
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disadvantage in the struggle to survive and reproduce. Natural selection operates on phenotype. Unequal mortality or reduced reproductive success across populations are associated with variation in phenotypes.
It is the animal with the longer legs that will be faster and better able to run away from predators.
It is the male with the brighter plumage that will be more attractive to females looking for a mate.
Directional selection selects occurs when

natural selection favors one extreme; disruptive selection occurs when natural selection favors both extreme phenotypes
29. Stabilizing selection occurs when an intermediate phenotype is favored during natural selection
30. A bottle neck is a drastic reduction in population
(volcanoes, earthquakes, landslides etc). The allele frequencies of the population before and after the bottle neck is different (therefore evolution) which may result in genetic drift and allele fixation (since the population is so small).
31. Founder effect - I n population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
32. Both natural selection and genetic drift lead to evolution process by varying the gene frequency of a population over time. Both these processes are involved in evolution and are not mutually exclusive. However, natural selection is the only process, which selects the best adaptive organism to the environment, and genetic drift reduces the genetic variation. These variations in genes or alleles are inheritable and genetic variation can be resulted by mutation, gene flow and sex.
33. Reproductive - is a mechanism that keeps species from mating with others.
Behavioral - s an important evolutionary mechanism that helps members of the same species identify each other as proper mates.
Geographic - is a term that refers to a population of animals, plants, or other organisms that are separated from exchanging genetic material with other organisms of the same species.
Temporal - Temporal isolation is genetic isolation achieved due to temporal differences in breeding.
For example, one population would be temporally isolated from another if it's breeding season was in the fall while the other's was in the spring.
34. divergent evolution is when 2 different species share the SAME ancestral origins (or a common ancestor) but have evolved differently

convergent evolution is when species with DIFFERENT ancestral origins have developed similar features. e.g. sharks and dolphins. they have a different ancestral origins but have developed similar features such as fins to suit their niche.
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The diversification of a group of organisms into forms filling different ecological niches.
36. Logistic and exponential growth