Chapter 13 and 14 study guide evolution,Chisholm.

What is the major biological event (extinctions, species diversifications) that happened in the Palaeozoic, Mesozoic and Cenozoic eras

-The Paleozoic Era, which ran from about 542 million years ago to 251 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another. Plants became widespread. And the first vertebrate animals colonized land -During the Mesozoic, or "Middle Life" Era, life diversified rapidly and giant reptiles, dinosaurs and other monstrous beasts roamed the Earth. The period, which spans from about 252 million years ago to about 66 million years ago, was also known as the age of reptiles or the age of dinosaurs. -The other two are the Mesozoic and Paleozoic Eras. The Cenozoic spans only about 65 million years, from the end of the Cretaceous Period and the extinction of non-avian dinosaurs to the present. The Cenozoic is sometimes called the Age of Mammals, because the largest land animals have been mammals during that time.

Be able to use a cladogram to describe which species are closer and lesser related and which traits they share or don't share.

A cladogram is a chart that is composed of many different clades or branches. Don't worry - we'll explain that sentence in more detail in a minute. A cladogram might remind you of a family tree since it too has many different branches, but it's set up in a slightly different format than a typical tree. It functions similarly to a family tree since the organisms listed are all related, but it is much more than just that.

define and give an example of genetic drift

A large population is suddenly reduced or isolated by geography or a natural event, Large populations become small and a gene that was evenly distributed is not evenly distributed anymore. Example Native American is nearly completely lacking B blood type

define and give an example of Population

A population is defined as a group of the same species living in a similar geographical area. AN example is over eight million people living in New York City.

analogous vs. homologous

Analogies are the result of convergent evolution. Interestingly, though bird and bat wings are analogous as wings, as forelimbs they are homologous. Birds and bats did not inherit wings from a common ancestor with wings, but they did inherit forelimbs from a common ancestor with forelimbs.

What was the importance to science of Darwin's​ trip on the Beagle?

Charles Darwin's 5-year voyage on the HMS Beagle lasted from 1831 to 1836. During this voyage, Darwin collected thousands of specimens to be analyzed. To create theories about natural selection .The main purpose of the voyage was actually to observe the coasts of other continents.

Describe three sources of genetic varation in offspring

Crossing over during prophase I of meiosis, independent orientation of chromosomes at. metaphase I, and random fertilization of gametes during fertilization.

What mechanism did Darwin propose for how species change over time?

Darwin defined evolution as "descent with modification," the idea that species change over time, give rise to new species, and share a common ancestor. The mechanism that Darwin proposed for evolution is natural selection.

How was Darwins thinking influenced by Lyell's book "Principles of Geology"?

Darwin read the anti-evolutionary books of both the Frenchman Georges Cuvier, who believed in numerous separate creations following episodes of extinction, and his fellow Englishman Charles Lyell, who is remembered as the founder of modern geology. Lyell's Principles of Geology was published in three volumes: The first volume was presented to Darwin by the Beagle's captain, Robert FitzRoy, before the ship set sail. The second volume, sent to Darwin while he was at sea, was a diatribe against Lamarck's transmutational ideas. Darwin always saw himself first and foremost as a geologist, and Lyell's work inspired him as he labored to understand the geology of South America. But Lyell's attacks on evolution arguably inspired Darwin in precisely the opposite direction.

Describe some of Darwin's findings from the journey regarding extinct and extant species?

Darwin was also struck by a second pattern. In different parts of South America, many species appeared to have been replaced by species that were similar yet distinct. For example, the common rhea, an ostrich-like bird that Darwin had been studying—and eating!—in northern Argentina, is replaced south of the Rio Negro by a smaller, browner species. In this case, Darwin focused on "allied" species that replace each other geographically—that is, across space rather than time.

How were Darwin's ideas in "The origin of species" different than the ideas presented by Lamarck years earlier?

Darwin's Theory: Evolution by Natural Selection Darwin's theory was presented in his book The Origin of The Species. Organisms with useful variations (traits that enhance survival) reproduce at a higher rate. This leads to changes in species. Example: There are five bears living in a cold area. Two of these bears have thick fur, so they stay warm and survive. The other three bears that do not have thick fur die of frostbite. The two surviving bears mate and their children inherit the thick fur

what does disruptive selection look like and what is it?

Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values.

compare and contrast convergent vs. divergent evolution

Divergent evolution occurs when two separate species evolve differently from a common ancestor. ... Convergent evolution occurs when species have different ancestral origins but have developed similar features.

What sorts of evidence of evolution can be found in the fossil record?

Evidence for Evolution. Fossils provide solid evidence that organisms from the past are not the same as those found today; fossils show a progression of evolution. Fossils, along with the comparative anatomy of present-day organisms, constitute the morphological, or anatomical, record.

How are populations bottlenecks related to genetic diversity?

Genetic drift can cause big losses of genetic variation for small populations.Population bottlenecks occur when a population's size is reduced for at least one generation. Because genetic drift acts more quickly to reduce genetic variation in small populations, undergoing a bottleneck can reduce a population's genetic variation by a lot, even if the bottleneck doesn't last for very many generations. This is illustrated by the bags of marbles shown below, where, in generation 2, an unusually small draw creates a bottleneck.

what is the only way that new allels ( traits) appear?

Genetic variation in a population is derived from a wide assortment of genes and alleles. The persistence of populations over time through changing environments depends on their capacity to adapt to shifting external conditions. Sometimes the addition of a new allele to a population makes it more able to survive; sometimes the addition of a new allele to a population makes it less able. Still other times, the addition of a new allele to a population has no effect at all, yet the new allele will persist over generations because its contribution to survival is neutral.

How can genetic drift be prevented?

Having homogenous populations. Genetic drift is the phenomena of allele frequencies stochastically varying because alleles are "randomly" assorted. The only way the frequency of an allele will be stable is if it has a frequency of 0 or 1 — to avoid genetic drift a loci must be fixed.

describe postzygotic (hybrid sterility, hybrid viability)

Hybrid zygote abnormality is a type of postzygotic barrier in which hybrid zygotes fail to mature normally. Hybrid infertility is a type of postzygotic barrier in which hybrids are incapable of producing offspring. for example the mule. the mule cant reproduce

What fossils did he find in South America that supported these ideas?

In 1832, as the Beagle was exploring the Bahia Blanca along the coast of Argentina, Darwin discovered the bones of fossil mammals at two localities. In a place where armadillos abounded, he was especially struck by what looked like the outer shell of an extinct form of an armadillo. In another location, he found the bones of extinct giant ground sloths. (Armadillos and sloths belong to the Order Edentata, a primitive group of mammals restricted to the South American continent.) Why would fossil remains and modern species found on the same continent resemble each other so closely,

Does mutation or adaptation respond to an organism needs? Elaborate

Mutation can respond to an organism needs, but not directly when to fufill there needs. Adaptation- a change or the process of change by which an organism or species becomes better suited to its environment

What type of traits does natural selection act on?

Natural selection acts on the phenotype, the characteristics of the organism which actually interact with the environment, but the genetic (heritable) basis of any phenotype that gives that phenotype a reproductive advantage may become more common in a population.

how can you predict the effect of directional, disruptive and stabilizing selection on genetic diversity

Natural selection can cause microevolution (change in allele frequencies), with fitness-increasing alleles becoming more common in the population. Fitness is a measure of reproductive success (how many offspring an organism leaves in the next generation, relative to others in the group). Natural selection can act on traits determined by alternative alleles of a single gene, or on polygenic traits (traits determined by many genes). Natural selection on traits determined by multiple genes may take the form of stabilizing selection, directional selection, or disruptive selection.

Does natural selection adapt a population to the current of future environment?

Natural selection is survival to the fittest, the process of adaptaion does not change the genotype directly, this meaning that it can or cannot prepare for the future environment

What is the smallest biological unit that can evolve?

Populations as the units of Evolution A population is: A group of individuals of the same species, living in the same place, at the same time The smallest biological unit that can evolve The total collection of alleles in a population at any one time is the gene pool.

How do polygenic traits' phenotypes differ from single-gene traits

Single gene traits: controlled by a single gene that has two alleles (ex: widow's peak) - only two phenotypes are possible - widow's peak or no widow's peak. Polygenic traits: controlled by two or more genes. Has 2 or more alleles. One polygenic trait can have many possible genotypes and phenotypes!

What does stabalizing selection look like and what is it?

Stabilizing selection (not to be confused with negative or purifying selection) is a type of natural selection in which the population mean stabilizes on a particular non-extreme trait value.

describe prezygotic ( temporal, behavioral)

TEMPORAL- Species that breed during different times of the day, different seasons, or different years cannot mix their gametes.In North America the geographic ranges of the eastern spotted skunk and the western spotted skunk overlap but the easter spotted skunk mates in late winter and the western spotted skunk mates in late summer BEHAVIROAL- Courtship rituals that attract mates and other behaviors unique to a species are effective reproductive barriers, even between closely related species. Such behavioral rituals enable mate recognition-a way to identify potential mates of the same species Blue footed monkeys, mate only after a courtship display unique to their species. Part of the "script" calls for the male to high-step, a behavior that calls the female's attention to his bright blue feet

define and give an example of bottleneck effect

The Bottleneck Effect occurs when there is a disaster of some sort that reduces a population to a small handful, which rarely represents the actual genetic makeup of the initial population. This leaves smaller variation among the surviving individuals. Genetic bottlenecks are defined by the textbook as "events in which the number of individuals in a population is reduced drastically." Essentially, this is genetic drift at it's finest. It occurs when the true frequency of alleles of a certain population, is not accurately presented in the new population. There is no other way to avoid a bottleneck effect because having a certain phenotype or genotype does not matter. This can have an extreme effect on the genetic diversity of the population. AN EXAMPLE of a bottleneck effect: Northern elephant seals have reduced genetic variation most likely due to being hunted. Hunting reduced their population size to as few as 20 individuals at the end if the 19th century. Since then their population has rebounded to over 30,000 but the genes still carry the marks of their bottleneck. They have much less variation than a population of Southern Elephant seals that have not been hunted..

define and give an example of founder effect

The Founder Effect is defined as a type of bottleneck, "a type of genetic drift describing the loss of the allelic variation that accompanies founding of a new population from a very small number of individuals (a small sample of a much larger source population). This effect can cause the new population to differ considerably from the source population." . Unlike bottlenecks, which persist as long as the effective population size remains low, a founder effect is an instant event. occurs when there is a lack of genetic variation due to a small mating population. The Founder Effect happens when there is a dramatic decrease in genetic diversity caused by the development of small colonies of individuals, from the original population, that remain isolated to other colonies. An example of the founder effect comes from the Afrikaner population of Dutch settlers in South Africa. This population has an abnormally high count of Huntington's Disease (nerve cells in brain degenerate) because the original Dutch settlers carried the gene with a higher frequency that the rest of the Dutch population.

How does Hardy-Weinberg can be used to show if evolution is happening/not?

The Hardy-Weinberg Principle states the conditions necessary for a population to remain in Genetic Equilibrium. If all the conditions are not met then evolution will occur. Random Mating: Sexual selection will alter the Gene Pool. Large Population: Small populations lead to random fluctuations of the Gene Pool. No Mutation: Genetic mutations add new genes the Gene Pool. No Migration: Individuals entering or leaving a population adds or subtracts genes from the Gene Pool. No Natural Selection: All individuals in the population must have an equal chance at surviving and reproducing.

Define Artificial selection

The breeding of plants and animals to produce desirable traits. Organisms with the desired traits, such as size or taste, are artificially mated or cross-pollinated with organisms with similar desired traits. (Compare natural selection.)

Describe how using pesticides leads to pesticide resistant organisms, and how this is an example of artificial selection

The chemical arsenal we have developed in an attempt to rid our homes of rodents and our crops of insects is losing its power. We have simply caused pest populations to evolve, unintentionally applying artificial selection in the form of pesticides. Individuals with a higher tolerance for our poisons survive and breed, and soon resistant individuals outnumber the ones we can control.

define and give an example of gene pool

The combination of all of the versions of all of the genes in a species is called the gene pool of the species.The gene pool increases when a mutation changes a gene and the mutation survives (see How Evolution Works for details). The gene pool decreases when an allele dies out. For example, let's say that we took the 1,000 fruit flies described in the previous paragraph and selected five of them. These five fruit flies might possess a total of only three alleles at locus 1. If we then let those flies breed and reproduce to the point where the population is once again 1,000, the gene pool of this 1,000 flies is much smaller. At locus 1, there are only three alleles among the 1,000 flies instead of the original 20 alleles.

Does natural selection create variation?

The genetic variation that occurs in a population because of mutation is random — but selection acts on that variation in a very non-random way: genetic variants that aid survival and reproduction are much more likely to become common than variants that don't.

what does % DNA similarity tell us about species relatedness?

These hybrid segments of DNA can be used to determine the evolutionary relatedness of organisms by examining how similar or dissimilar the DNA base pair sequences are .The technique of DNA hybridization is based on two principles: the first, that double strands of DNA are held together by hydrogen bonds between complementary base pairs, and the second is that the more closely related two species are, the greater will be the number of complementary base pairs in the hybrid DNA. In other words, the degree of hybridization is proportional to the degree of similarity between the molecules of DNA from the two species.

why is this concerning in endangered species like cheetahs?

This event caused an extreme reduction of the cheetah's genetic diversity, known as a population bottleneck, resulting in the physical homogeneity of today's cheetahs. Poor sperm quality, focal palatine erosion, susceptibility to the same infectious diseases, and kinked tails characteristic of the majority of the world's cheetahs are all ramifications of the low genetic diversity within the global cheetah population.

what sorts of conditions tend to lead to genetic drift?

Unlike natural selection, genetic drift does not depend on an allele's beneficial or harmful effects. Instead, drift changes allele frequencies purely by chance, as random subsets of individuals (and the gametes of those individuals) are sampled to produce the next generation. Every population experiences genetic drift, but small populations feel its effects more strongly. Genetic drift does not take into account an allele's adaptive value to a population, and it may result in loss of a beneficial allele or fixation (rise to 1 0 0 % 100%100, percent frequency) of a harmful allele in a population. The founder effect and the bottleneck effect are cases in which a small population is formed from a larger population. These "sampled" populations often do not represent the genetic diversity of the original population, and their small size means they may experience strong drift for generations.

can individuals evolve? elaborate

Yes, because of mutations are sporadic .One common misconception about evolution is the idea that individuals can evolve, but they can only accumulate adaptations that help them survive in an environment. While it is possible for these individuals in a species to mutate and have changed made to their DNA, evolution is a term specifically defined by the change in DNA of the majority of a population. In other words, mutations or adaptations do not equal evolution.

Summarize darwins theory of natural selection in at least 5 steps

competition, adaption, variation, overproduction, speciation

What does directional selection look like and what is it?

directional selection is a mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.

what criteria is used to define organism as member of the same species

marsupial and placental

define and give an example of biological fitness

means the ability to survive to reproductive age, find a mate, and produce offspring. Basically, the more offspring an organism produces during its lifetime, the greater its biological fitness. Mr Chisholm brother and him, not a good example but the only one I can think of... the brother has 6 kids while he only had 1

define and give an example of gene flow

movement of new genes in a population Examples of this include a bee carrying pollen from one flower population to another, or a caribou from one herd mating with members of another herd. ... Genes can come in different forms called alleles.

define and give an example of sexual selection

natural selection arising through preference by one sex for certain characteristics in individuals of the other sex. For example, extravagant and colorful tail feathers or fins are likely to attract predators as well as interested members of the opposite sex.

define and give an example of Natural selection

natural selection is survival of the fittest, as time passes by special adaptation for survival arise causing new species to evolve. An example is the mice on the top the black volcano helping them adapt to their new environment by changing their coat color.

What types of evidence are used to classify organisms into groups?

taxonomy