Chapter 11 Bio

Adaptation

a heritable trait or behavior in an organism that aids in its survival in its present enviroment.

founder effect

a magnification of genetic drift in a small population that migrates away from a large parent population carrying with it an unrepresentative set of alleles

1. Figure 11.7 Do you think genetic drift would happen more quickly on an island or on the mainland?

island because there is a smaller population and it is easier for genes to spread to organisms because there is less of them

Describe the basic principles of the theory of evolution

1. Indivduals within a species vary, also known as variation, some of the variations are heritable. Each species has traits determined by inheritance. Inherited traits passed from parents to offspring determine the characteristics of the offspring. Most species produce more offspring each year than the environment can support. Only surviving individuals breed and can pass on their genes to the next generation. Lastly survival of the fittest, Indivduals reproduce, adding their genes to the succeeding generations. The traits that helped these organisms to survive will be passed on to their offspring, also known as natural selection.

Alfred Russel Wallace and Charles Darwin both described the process of evolution by natural selection independently (at the same time in history). Describe the three basic principles of natural selection.

1. Most characteristics are inherited 2. More offspring are produced than able to survive. 3. Offspring with more favorable traits will survive and have more offspring than those indivduals with less favorable traits.

18. Why do scientists consider vestigial structures evidence for evolution?

A Vestigal structure is an example of a homologous structure that has apparently been reduced through evolution to a non-functional state because its function is no longer utilized by the species exhibiting it.

What was Jean-Baptiste Lamarck's explanation for evolutionary change? Why doesn't this work with what we know today about the way traits are inherited?

He proposed that characteristics acquired over the course of an individual's lifetime could be passed to the offspring. This doesn't work with what we know about the way traits are inherited because he didn't have evidence for it, for example if a dog cuts its ears short after being born, it will not mean that their puppies will also have short ears. And also with the study of genetics, Mendel was able to prove that genes are the only traits that can be passed on that can not be affected by the outside world.

Describe the basic difference between allopatric and sympatric speciation

In allopatric speciation, groups from an ancestral population evolve into separate species due to a period of geographical separation. In sympatric speciation, groups from the same ancestral population evolve into separate species without any geographical separation.

The bones in the fore-limbs (arms) of all animals with backbones are homologous structures. They are anatomically similar (one upper arm bone, two lower arm bones) because the common ancestor also had similar arm bones. Is the current diversity of arm (fore-limb) structure in animals with backbones an example of convergent evolution or divergent evolution?

It's convergent evolution because there are similar structures within the animals and their ancestors

How can homologous structures and vestigial structures be used to demonstrate shared ancestry (that different species are descended from a common ancestor)?

The main difference between homologous structures and vestigial structures is that homologous structures are the similar anatomical structures inherited from a common ancestor whereas vestigial structures are the anatomical structures which have reduced their size as they are no longer used

Is the process of adaptation something that happens to an individual organism or to a population? In other words, can an individual change their phenotype to fit their surroundings OR does the overall phenotype of the population change in response to the selective pressures of the surroundings? Hint: think about Lamarck vs. Darwin

The process of adaptation happens to a population. The overall phenotype of the population changes in response to the selective pressures of the surrounding . According to natural selection individual organisms or phenotypes that possess favorable traits are more likely to survive and reproduce

How can molecular biology (DNA and protein sequencing) be used to demonstrate shared ancestry?

The sequences of the molecule in the different species must be compared so that the number of amino acid or nucleic acid bases that differ can be counted. ... Depending on the rate of substitution, molecules may be used to determine ancient relationships or relatively recent ones.

17. Describe natural selection and give an example of natural selection at work in a population.

The theory of natural selection stems from the observations that some individuals in a population survive longer and have more offspring than others, thus passing on more of their genes to the next generation. For example, a big, powerful male gorilla is much more likely than a smaller, weaker gorilla to become the populations silverback, pack leader. This silverback will have more mates and father more offspring sharing half of his genes. These offsprings will grow big and strong. Over time the genes for large size in the population will grow and the population will grow in size.

Explain how a natural disaster such as a forest fire or tsunami could result in the "bottleneck effect".

a sudden change in the environment may reduce the size of the population which can cause the bottleneck effect. Its named that because the individuals that due survive have greatly reduced genetic diversity compared to the original population since fewer individuals means there are fewer genotypes.

10. Which situation would most likely lead to allopatric speciation? a. A flood causes the formation of a new lake. b. A storm causes several large trees to fall down. c. A mutation causes a new trait to develop. d. An injury causes an organism to seek out a new food source.

a. A flood causes the formation of a new lake.

13. The word "theory" in theory of evolution is best replaced by ________. a. fact b. hypothesis c. idea d. alternate explanation

a. fact

divergent evolution

an evolution that results in different forms in two species with a common ancestor

convergent evolution

an evolution that results in similar forms on different species

12. Which variable increases the likelihood of allopatric speciation taking place more quickly? a. lower rate of mutation b. longer distance between divided groups c. increased instances of hybrid formation d. equivalent numbers of individuals in each population

b. longer distance between divided groups

7. In which of the following pairs do both evolutionary processes introduce new genetic variation into a population? a. natural selection and genetic drift b. mutation and gene flow c. natural selection and gene flow d. gene flow and genetic drift

b. mutation and gene flow

2. Which scientific concept did Charles Darwin and Alfred Wallace independently discover? a. mutation b. natural selection c. overbreeding d. sexual reproduction

b. natural selection

14. Why are alternative scientific theories to evolution not taught in public school? a. more theories would confuse students b. there are no viable scientific alternatives c. it is against the law d. alternative scientific theories are suppressed by the science establishment

b. there are no viable scientific alternatives

4. What is the difference between micro- and macroevolution? a. Microevolution describes the evolution of small organisms, such as insects, while macroevolution describes the evolution of large organisms, like people and elephants. b. Microevolution describes the evolution of microscopic entities, such as molecules and proteins, while macroevolution describes the evolution of whole organisms. c. Microevolution describes the evolution of populations, while macroevolution describes the emergence of new species over long periods of time. d. Microevolution describes the evolution of organisms over their lifetimes, while macroevolution describes the evolution of organisms over multiple generations.

c. Microevolution describes the evolution of populations, while macroevolution describes the emergence of new species over long periods of time.

6. Galápagos medium ground finches are found on Santa Cruz and San Cristóbal islands, which are separated by about 100 km of ocean. Occasionally, individuals from either island fly to the other island to stay. This can alter the allele frequencies of the population through which of the following mechanisms? a. natural selection b. genetic drift c. gene flow d. mutation

c. gene flow

8. The wing of a bird and the arm of a human are examples of ________. a. vestigial structures b. molecular structures c. homologous structures d. analogous structures

c. homologous structures

3. Which of the following situations will lead to natural selection? a. The seeds of two plants land near each other and one grows larger than the other. b. Two types of fish eat the same kind of food, and one is better able to gather food than the other. c. Male lions compete for the right to mate with females, with only one possible winner. d. all of the above

d. all of the above

9. The fact that DNA sequences are more similar in more closely related organisms is evidence of what? a. optimal design in organisms b. adaptation c. mutation d. descent with modification

d. descent with modification

Explain how the Amish (Dutch settlers in America) have experienced the "founder effect".

founder affect is when a new colony is started by a few members of the original population. Since the Amish population is small in size and they marry amongst themselves, there is reduces genetic variation from the original population.

Is genetic drift more important in small populations, large populations, or both?

genetic drift occurs in all populations of non-infinite size, but are the strongest in small populations.

Mutation

heritable changes in genetic information

21. How does the scientific meaning of "theory" differ from the common, everyday meaning of the word?

in science a theory is a widely accepted and rigorously tested statement, to where the everyday use is more of a guess

19. Why do island chains provide ideal conditions for adaptive radiation to occur?

islands are great for adaptive radiation, because the species can arrive all together and slowly disperse through the chain of the island and then they can evolve and adapt to their new environment however different they may be form the original or even new sister species

Macroevolution

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

What is the ultimate source of all genetic variation (new alleles)?

mutations

The textbook recognizes four factors that change populations (mechanisms of evolution). What are they?

natural selection, mutation, genetic drift, and migration (gene flow)

What can the geographic distribution of species tell us about their relatedness? For instance, if species are found in areas that were once part of the same continent (or found on the same island archipelago), might this mean they share a common ancestor?

patterns in the distribution of living and fossil species tell us how modern organisms evolved from their ancestors.

homologous structures

structures that are similar in different species of common ancestry

If two related bird species live in the same area but the males are colored differently and sing different songs, would this more likely be a result of allopatric speciation or sympatric speciation?

sympatric speciation

Microevolution

the changes in a populations genetic structure

Variation

the variety of alleles in a population

genetic drift

the effect of chance on a populations gene pool

natural selection

the greater relative survival and reproduction of individuals in a population that have favorable heritable traits, leading to evolutionary change

bottleneck effect

the magnification of genetic drift as a result of natural events or catastrophes

Evolution

the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.

20. Two species of fish had recently undergone sympatric speciation. The males of each species had a different coloring through which females could identify and choose a partner from her own species. After some time, pollution made the lake so cloudy it was hard for females to distinguish colors. What might take place in this situation?

the two species would begin to breed with each other and if they can produce good, strong, fertile offspring they would continue to mate but if not then the species would adapt to be able to tell he other species apart

22. Explain why the statement that a monkey is more evolved than a mouse is incorrect.

this statement is incorrect because the monkey and the mouse both are evolving to different goals and they need different things so you cannot compare them

Could gene flow increase variation in a small population?

yes it can, while gene flow between between genetically distant populations can reduce the genetic difference between populations.