exam 4: chapter 27

If the frequency of the dominant gene is 0.7, what is the frequency of the recessive gene?

0.3 (or 1.00 - 0.7)

The earliest forms of life on earth are found in rocks that are estimated to be

3.5 billion years old.

microevolution

A change in the gene pool that involves the relative frequencies of alleles in a population over a number of generations.

Adaptation

A characteristic that improves an individual's ability to survive and reproduce in a particular environment.

population

A group of individuals of the same species that live in the same area and interbreed.

Fossil

A preserved remnant or impression of an organism that lived in the past.

explain why natural selection is the only mechanism that leads to adaptive evolution

Although gene flow and genetic drift can increase frequency of advantageous alleles in a population, they can also decrease the frequency of advantageous alleles. Only natural selection can consistently increase the frequency of advantageous alleles.

cladistics

An approach to systematics in which organisms are placed into groups called clades based primarily on common descent.

adaptive radiation

An evolutionary pattern in which many species evolve from a single ancestral species

Which fossil evidence is considered an intermediate between reptiles and birds?

Archaeopteryx

the three-domain system

Bacteria, Archaea, Eukarya

How does breeding domestic animals, such as dogs, provide support for Darwin's theory of evolution by natural selection?

Breeding dogs shows the process of natural selection. All dogs come from wolves and when breeders pick certain attributes they like, nature does the rest by allowing the dogs with the best attributes suitable to survive in their environment populate, and, as a result, variety is produced. The different breeds can technically be considered "different species" because of the diversity that is created over time.

how do the bottleneck effect and the founder effect influence microevolution

Catastrophes such as hurricanes, floods or fires may kill large numbers of individuals leaving a small surviving population that is unlikely to have the same genetic makeup as the original population. It may cause populations to have low levels of genetic variation due to the legacy of the genetic drift that occurred when the population was small.

gene pool

Consists of all copies of every type of allele at every locus in all members of the population.

Explain how Darwin's voyage on the Beagle influenced his thinking

Darwin's journey began in 1831 and was a 5 year trip from Western Europe to South America, New Zealand, around the Cape of Good Hope in southern Africa and back to Europe. He realized from his experiences on the ship that Earth was very old and was constantly changing.

cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Charles Darwin

English naturalist. He studied the plants and animals of South America and the Pacific islands, and in his book On the Origin of Species by Means of Natural Selection (1859) set forth his theory of evolution.

phylogeny

Evolutionary history of a species or group of species.

When Darwin returned from his voyage on the HMS Beagle, he began to contemplate how one species could become another species. What was it about the Galapagos Finches that helped him develop his ideas about evolution?

He noticed a difference in the beaks of the finches. One had a thin, delicate beak for insects. The other had a big, heavy beak that can be used to crack nuts. He figured that the different geographical areas is what accounted for differences. And, over time, those differences became more profound.

Who was the scientist that developed a theory of evolution by natural selection that was identical to Darwin's?

In June 1858, the scientist/naturalist Alfred Russel Wallace. He had been talking to Darwin for a while. He had exactly the same idea as Darwin, though he claimed the idea came to him while he was delirious with a Malarian fever. Unlike Darwin, however, he did not have 20 years of evidence to back it all up.

epigenetic inheritance

Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence.

describe at least two examples of natural selection known to occur in nature

Insects against pesticides Sickle cell anemia and Malaria

Darwin's theory implies that there should be connections between the great animal groups, but these transitions were not known in the fossil record until the discovery of "Archeopteryx". What two animal groups is "Archeopteryx" a combination of?

It appeared to be like a bird with claws, jaws, feathers, and a tail. It is thought to be part reptile, part bird.

explain the significance of the Hardy-Weinberg to natural populations

It can be used to test whether or not evolution is occurring in a population. Public health scientist use it to estimates how many people carry alleles for certain inherited diseases (PKU)

What did the new technology to map the sea floor in the 1960's reveal about the continents? How did this help explain the global distribution of species?

It showed continents had shifts and were still moving. New rocks comes from deep below the crust and float away, carrying continents with them. Amphibians then, for example, traveled on different fragments that broke off, which explained the distribution of species.

Compare Lamarck's and Darwin's Ideas about how evolution takes place

Lamarck suggested that the characteristics, or traits, developed during a parents organism's lifetime are inherited by its offspring while Darwin suggested that animals go through evolution due to natural selection

describe how mutations contribute to genetic diversity

Mutations that are not repaired can become a permanent part of the genetic makeup of the cell. If these mutations occur in reproductive cells, they can be passed on to the next generation. The mutation is then a part of the heritable variability of the population. The new trait is now subject to the forces of natural selection and will become more permanent if it confers a selective advantage

Which of the following is true about natural selection? It always selects for more complex forms. It assures the survival of each fit individual. It acts on genotypes rather than phenotypes. It always selects for forms that are a mutated variation. On average, it favors the survival of young with adaptive characteristics.

On average, it favors the survival of young with adaptive characteristics.

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

How did Marie Currie's discovery of radioactive elements, like Uranium, help support Darwin's theory?

She discovered some rocks have uranium that decay over time at steady rate (radiation). There is a method of measuring changes in radioactivity, which helps to show how old rocks are. One rock's crystals were shown to be 562 million years old, which supports Darwin's theory because that shows there is enough time for natural selection and evolution to produce fossils which eventually leads to plants and animals.

Analagous Structures

Similar function but different structure - does not show common ancestry - Ex: butterfly wing and bat wing)

homologous structures

Structures in different species that are similar because of common ancestry.

allopatric speciation

The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.

sympatric speciation

The formation of new species in populations that live in the same geographic area

inheritance of acquired characteristics

The hypothesis that organisms' bodies change during their lifetimes by use and disuse and that these changes are inherited by their offspring

When Darwin published "The Origin of Species" in 1859, what was the most controversial part of the book for most people?

The most controversial part was the implication were not created by God, but descended by apes. Church leaders attacked it and thought it was offensive and denied the story of creation as told in the Bible. He implied life was simple at first, and then became more complex.

Taxonomy

The scientific study of how living things are classified

punctuated equilibrium

The theory that species evolve during short periods of rapid change

How has DNA sequencing and modern genetics supported Darwin's theory?

Two researches built models to show the structure of complex molecules and DNA. The chains that circle the rod and entwine with each other represent the double helix. By understanding DNA and its double helix structure, we know that a gene taken from one animal can be put inserted another. For example, a gene in jellyfish that make them luminous can be implanted in a rat can make them too. DNA fingerprinting can establish if a man is the father of a child. It can also show if one animal is related to another. For example, it shows that kangaroos are closely related to koalas, that shrews have bats as cousins, and that elephants are like sea cows. Modern genetics confirm that all life is related, supporting Darwin's theory of natural selection and evolution because it shows how species are related through genetics.

genetic drift

a change in the gene pool of a small population due to chance -there are two ways that a population shrinks down to a size where there is a genetic drift (bottleneck and flounder)

explain the five conditions required for the Hardy-Weinberg equilibrium to natural populations

a very large population no gene flow between populations no mutations random mating no natural selection

explain how artificial selection is similar to natural selection

artificial selection: 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. ex. plant breeders natural selection: the process where organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution. The similarities are that in both, only certain individuals in a population produce new individuals

explain how biogeography supports evolution

biogeography: the study of geographic distribution of species When Darwin visited the Galapagos he saw that animals there resembled similar animals on South American mainland Yet, there was diversity in them that proves evolution. For example, some marsupials (mammals that complete embryonic development outside the uterus; pouch) were different.

explain how comparative anatomy supports evolution

comparative anatomy: the comparison of body structures you can see how the limbs of humans, cats, whales, bats descended from a common ancestor and diversely adapted (variations on a common theme)

Almost all living organisms use DNA, ATP, and the same DNA triplet code. This is an example of evolution based on _______________

comparative biochemistry

explain how comparative embryology supports evolution

comparative embryology: branch of embryology that compares and contrasts embryos of different species to show how they are related comparing early stages of development reveals similarities not visible in adult organisms -ex. all vertebrate embryos have a development stage in which structures called pharyngeal pouches appear on the side of the throat (fish, frogs, snake, birds) all look the same and more distinctive features develop later

transitional links

evidence of evolution, typically fossils, that bear a resemblance to two groups that in the present day are classified separately

The organisms examined by Darwin on the Galapagos Islands that were most important in his development of the theory of natural selection were

finches

explain how fossil evidence supports evolution

fossil evidence: the ordered sequence of fossils as they appear in the rock layers, marking the passage of geologic time. It supports evolution because it shows gradual changes in species, and reveals how different organisms came to be what they are ex. young strata are on top of older ones, so the position of fossils in the strata reveal their relative age (ages of fossils can be confirmed with radiometric dating). The oldest fossils are prokaryotes (3.5 billion years ago) and fossil evidence shows they are the ancestors of all life and paleontologists have found a series of transitional fossils providing evidence that one group of birds desenended from a branch of dinosaurs and whales have forelegs in the form of flippers, but with the bones of ancestral legs

What evidence for evolution uses impressions of plants and animals pressed into sedimentary rock?

fossil record

bottleneck effect

genetic drift due to a large reduction in population size due to disasters such as earthquakes, floods, and fire that may kill large numbers of individuals, producing a small surviving population that is unlikely to have the same genetic makeup as the original population. -by chance, some allele may be over or underrepresented by among the survivors -ex. cheetahs: genetic variability is very low (same genes helped them to survive), so they cannot adapt to new environments or disease (loss of individual variation)

flounder effect

genetic drift resulting from the establishment of a small, new population who's gene pool differs from that of the parent population -(individuals on island, genetic makeup doesnt match the gene pool of larger population where they originally came from). If the colony succeeds, random drift will continue to affect the frequency of allele until the population is large enough for genetic drift to be minimal ex. the founder effect definitely contributed to the evolutionary divergence of the finches and other organisms that arrived as strays on the remote Galápagos Islands

taxon

group or level of organization into which organisms are classified

macroevolution

large-scale evolutionary changes that take place over long periods of time

Fitness of an individual

measured by the number of fertile offspring produced throughout its lifetime

What is the term used to describe the accumulation of small changes in the gene pool of a species over time?

microevolution

explain how molecular biology supports evolution

molecular biology: branch of biology that deals with the structure and function of macromolecules (e.g. proteins and nucleic acids) essential to life scientists can compare DNA and see how many nucleotide sequences match up and if the 2 species share a common ancestor (greater the difference, less likely to share a common ancestor) -ex. chimps and humans

If the Hardy-Weinberg equilibrium is met, what is the net effect?

no evolution because the alleles in the population remain the same

how does non-random mating affect genetic diversity

non-random mating: any degree of preferential matings between individuals that results in particular genotypes mating more frequently than would be -results in genotypes not occurring in frequencies predicted by H.W. equilibrium

prezygotic isolating mechanisms

occurring before breeding; produces a fertilized egg, or zygote

postzygotic isolating mechanisms

operate after fertilization has occurred to ensure that the resulting hybrid remains infertile

How is the Hardy-Weinberg equilibrium estimated?

p^2+2pq+q^2=1 p and q represent frequencies of alleles D and d

vestigial structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.

Which of these conditions is NOT among the requirements of the Hardy-Weinberg equilibrium? no selection of one genotype over another small population with genetic drift no net mutations sexually reproducing and random mating population no net migration of alleles into or out of the population

small population with genetic drift

gradualistic model

speciation occurs after population isolation, with each group continuing slowly down its own evolutionary path

distinguish between stabilizing selection, directional selection, and disruptive selection. Give an example of each

stabilizing section: when individuals near the center of the curve have higher fitness than individuals at either end of the curve. An example would be birth weight. Babies that are born too small can lose heat too easily and may die, whereas babies being born too large can lead to complications during childbirth and the death of the mother or the baby. directional selection: when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end. Example is beak sizes in finch populations. disruptive selection: when individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle. Example is peppered moth in England. The peppered moth may be a light color or a dark color, with very few individuals being a color in between the two extremes.

systematics

study of the diversity of life and the evolutionary relationships between organisms

phylogenetics

the analysis of evolutionary, or ancestral, relationships between taxa

Lamarck's theory of evolution included the idea that: the continual stretching of giraffe's necks to reach leaves led to longer necks. species are only produced through special creation. species are fixed and unchanging over time. organisms are acted on by the environment. local catastrophes cause mass extinctions of species.

the continual stretching of giraffe's necks to reach leaves led to longer necks.

Speciation

the formation of new and distinct species in the course of evolution.

Darwin's Theory of Evolution

the idea that living species are descendants of ancestral species that were different from present-day ones and that natural selection is the mechanism for evolutionary change.

shared derived traits

traits that organisms have acquired from their ancestors and share with other members of the group

Anatomical features that are fully developed and functional in one group of organisms but reduced and functionless in a similar group are termed _________

vestigial

gene flow

where a population may gain or lose alleles when fertile individuals move into or out of the population or when gametes are transferred between populations -tends to reduce differences between populations (ex. humans today move more around the world than in the past, and gene flow has become an important agent of evolutionary change in previously isolated human populations)