Bio Anthro

Front 1

1. Give a brief definition of evolution (in the sense of an observable fact).

Back 1

Change in the frequency or magnitude of heritable characteristics of a population of organisms
over generations

Front 2

2. Give an example of evolution that has actually been observed.

Back 2

Change in frequency of dark and mottled moths in Manchester before to after the Industrial
Revolution.

Front 3

3. Explain what Darwin observed during his travels on the Beagle that convinced him that evolution had occurred. Describe both the observations and his reasoning about them.

Back 3

Animals and plants were well adapted to their environments, yet similar to others in nearby areas. That is, a species on an island would be adapted to the island, but would seem to be a variant of a similar species with a different adaptation on the nearby mainland coast. Similar species are often found near each other, and more different ones are often found further away, even if the distant environments seem similar. This suggested to Darwin that the similar species were similar because they both arose from some ancestral form found in that area that then changed slightly to fit each location.

Front 4

4. Define catastrophism.

Back 4

The view that geological strata and fossils are explicable by a series of huge events unlike any in known history, like world-covering floods that killed and buried all living things, which then started anew.

Front 5

5. Is Darwin’s theory of evolution catastrophist, or uniformitarian? Why?

Back 5

Uniformitarian, because it involves only processes that we observe today (reproduction of offspring that imperfectly resemble their parents, many not surviving or reproducing, etc.), but acting over a long time

Front 6

6. List and briefly explain the three conditions (“postulates”) that underlie Darwin’s theory of evolution.

Back 6

1. More organisms are born than survive and reproduce.
2. Individuals vary in ways that affect how well they survive and reproduce.
3. Offspring tend to resemble their parents.

Front 7

7. If Darwin’s three conditions or postulates are true, what happens?

Back 7

Natural selection. If the selection is directional, it causes evolution. If the selection is stabilizing,
no evolution occurs.

Front 8

8. Imagine a study of a population of a certain species of flea living in a container in a lab. The researchers make every measurement and observation imaginable of every individual flea over 500 generations, and absolutely nothing about the population of fleas changes over time.
a. Did evolution occur?
b. Did natural selection occur? Explain.

Back 8

a. No. OR None that could be detected
b. Yes. The most successful type must have already been the most common type, so no change occurred. This is called stabilizing selection.

Front 9

9. If we find a watch, we can justifiably infer a watchmaker. What is so different about living things that we don’t necessarily have to infer a designer? Explain briefly.

Back 9

Living things reproduce themselves imperfectly, making all three postulates possible, and thus making the process of evolution possible – in fact, inevitable. Watches do not reproduce, so there can be no variation in how well they survive and reproduce, so there can be no natural selection, so they cannot evolve; they must be made by a watchmaker.

Front 10

10. Imagine that while studying mythical Malawi marsh mice, Dr. Smith observes that adult mice with longer-than-average tails have twice as many babies than do mice with average or shorter tails. On the other hand, their principle predator usually catches the mice by their tails, so mice with shorter-than-average tails are 10% more likely to survive to adulthood. Dr. Smith plans to collect detailed census data of these mice for the next twenty years.
a. Assuming that no other factors come into play, should Dr. Smith expect the average length of the mice’s tails to stay the same, get longer, or get shorter?
b. Why?
c. Assuming that no other factors come into play, by the end of the project, should Dr. Smith expect the mice to be better adapted to avoid predation, or less well adapted?

Back 10

a. The tails should get longer.
b.The longer-tailed mice leave many more offspring, but have only a slightly lower rate of survival. Even though slightly fewer longer-tailed mice survive to adulthood, those that do survive leave many more offspring each than do the average and shortertailed
mice. These additional offspring of the survivors more than make up for the fact that each long-tailed mouse was a bit less likely to survive long enough to breed.
c. They will be worse adapted to avoid predation – but better adapted to leave offspring.

Front 11

11. Explain what is meant by the phrase “Selection acts on individuals, and affects populations”.

Back 11

Selection is the process that determines which individuals survive and reproduce, and how much.
It acts on specific individuals that live, die, mate often or rarely, etc. It affects populations in that the heritable features of the individuals that do reproduce remain common or become more common in the next generation. That is, the frequency of traits in the population may change, or the average type in the population may change.

Front 12

12. Why does evolution often result in strange, cobbled-together features, like the trouble-prone knees and backs of humans?

Back 12

Because evolution can only work by modifying whatever came before. Natural selection is simply
the accumulation of whichever variants of existing features cause the organism to leave more offspring. So evolution only causes changes that are improvements to reproductive success at every step. This accumulation of tiny improvements may not lead to a particularly good solution.

Front 13

13. What is punctuated equilibrium?

Back 13

The notion that the traits of populations tend to stay roughly the same for a long time (periods of “equilibrium”), but occasionally evolve rapidly to a new, stable configuration (in events of rapid change that “punctuate” the usual periods of equilibrium).

Front 14

14. Is evolution a slow process, or a fast one? Explain.

Back 14

People who study living organisms find that evolution can be fast, with notable changes occurring in just one or a few generations, as in the case of the Galapagos finches during a drought. But they find that these changes often reverse themselves, as the finches did when the weather returned to normal. People who study fossils usually see evolution as slow. This is
because they have few specimens, widely spaced in time. The rapid, back-and-forth changes seen in living organisms probably did occur, but by looking at just a few examples over a long period, these changes are averaged out, and the long-term rate of change looks slow. [A graph?]

Front 15

15. Macroevolution is

Back 15

Evolution that creates new species.

Front 16

16. According to the biological species concept, what allows species to remain different from
each other, or evolve further apart? Explain.

Back 16

Reproductive isolation between the species
OR Lack of gene flow between the species
OR There is no exchange of genes between the species … so their genes do not get mixed together, which would keep them similar; without gene flow, nothing prevents them from evolving in different directions

Front 17

17. According to the ecological species concept, what is the key process that allows species to remain different from each other?

Back 17

Stabilizing selection (“Natural selection” is also technically correct, but not complete. Stabilizing selection is indeed one kind of natural selection, but natural selection can also be directional, and directional selection is not what underlies the ecological species concept.)

Front 18

18. According to the ecological species concept, how does the process you named in question 3 keep species different from each other?

Back 18

The common type of each species survives and reproduces better than any hybrids or intermediate types.

Front 19

19. What is a chronospecies (or paleospecies)?

Back 19

A kind of organism that is sufficiently different from its ancestors as the result of evolutionary change within a single line of descent, that is, as a result of anagenesis
OR a species that arose due to accumulated change in a single population or species, rather than a split into populations of two kinds that live at the same time. Chronospecies are arbitrary divisions of a continuous sequence of change.

Front 20

20. Describe the situation required for allopatric speciation to occur.

Back 20

Two populations that are geographically isolated from each other (and thus reproductively
isolated from each other) which experience different conditions, so that one or both change enough to become a species distinct from the other.
OR Two populations that live in different territories, preventing gene flow between them.

Front 21

21. What is meant by punctuated equilibrium?

Back 21

A pattern of changing rates of evolution in which species evolve slowly or not at all for long periods of time (periods in which they are in “equilibrium” with their conditions), but occasionally evolve rapidly to a new equilibrium state (a “punctuation” event).

Front 22

22. Fill in the blanks. Mendel’s “particles” of inheritance are now called ________ which often come in two or more variant forms called ______________.

Back 22

genes, alleles

Front 23

23. The ability to roll one’s tongue is thought to be a simple Mendelian trait, like pea seed color.
About 70% of Europeans can roll their tongue; about 30% cannot. Based on this, you can infer that the allele for tongue-rolling is (circle one):
Dominant
Recessive
Co-dominant
Can't tell

Back 23

can't tell

Front 24

24. In humans, free-hanging earlobes (F) are dominant, and attached earlobes (a) are recessive.
Bob is homozygous dominant.
a. Bob’s genotype (with regard to earlobes) is?
b. Bob’s phenotype (with regard to earlobes) is?
c. Bob’s girlfriend Jane is heterozygous. Fill in and fully label the Punnett square below to represent the gametes that Bob and Jane produce, and the genotypes and phenotypes of the offspring they could have.
d. Jane gives birth to a son with attached earlobes. What can you conclude?
e. Bob’s neighbors, Mr. and Mrs. Jones, both have free-hanging earlobes. Can they have a child with attached earlobes? Explain.

Back 24

a. FF b.Free-hanging
c. Fa/FF Punnet square, all Free hanging
d. Bob is not the biological father.
e.Maybe: Both parents have at least one F allele, singe they have the dominant free-hanging trait. If both are both heterozygotes (Fa), then they can have a child with attached earlobes. The offspring could get the recessive a allele from each parent, resulting in a genotype of aa. With only the recessive alleles, the offspring would express the attached earlobe trait. But if one or both parent is homozygous (FF), then the offspring necessarily will get an F allele, and so will express the dominant free-hanging trait; they cannot produce an aa child.

Front 25

25. Through the process of ________, the sequence of ______ in a long segment of __________ determines the sequence of______ in a long segment of __________, which in turn, through the process of ______, determines the sequence of ________ in a __________.

amino acid, base (or nucleotide base), carbohydrate, catalyst, centromere, chromosome, division (or cell division), meiosis, mitosis, DNA, RNA, mRNA, tRNA, nucleus, protein, reduction, replication, reproduction, ribosome, transcription, translation, transmission

Back 25

transcription, nucleotide bases, DNA, nucleotide bases, mRNA, translation, amino acids, protein

Front 26

26. Errors occasionally occur in the processes in Q1.
a. Are these errors likely to affect the next generation in some way?
b. Why or why not?

Back 26

a. no
b. The processes above affect only the proteins synthesized in one cell. They do not affect the genetic code that offspring inherit.

Front 27

27. What are the two types of cell division called?

Back 27

mitosis and meiosis

Front 28

28. What is the overall difference between the two types of cell division?

Back 28

mitosis results in two daughter cells genetically identical to the parent cell (OR both diploid) meiosis results in gametes that have only half the complement of DNA (OR they are haploid)

Front 29

29. What is the result of crossing over?

Back 29

It produces gametes that carry chromosomes that combine parts of both chromosomes of the parent. OR It reshuffles the alleles of a parent so that the offspring can get any combination of the parent’s alleles. OR other ways of saying this.

Front 30

30. Why would natural selection be expected to favor organisms that were developing sexual
reproduction and crossing over?

Back 30

Because both increase the variability of the offspring (OR the number of new combinations produced in the offspring, etc.). This gives selection more alternatives to weed out or favor, which would allow the population to evolve more rapidly in response to changing conditions. Organisms that evolve more rapidly are more likely to succeed and persist in changing conditions.

Front 31

31. Mendelian genetics initially seemed to apply only to dichotomous or discontinuous traits. How can Mendel’s model explain continuously variable traits?

Back 31

Continuously variable traits are controlled by many pairs of loci, not just one pair. Each pair of
loci follows Mendel’s simple rules, but because many pairs are involved, there are many
combinations that result in many different genotypes. Because variations in the environment cause some variation in the phenotypes that result from each genotype, the gaps between the many possibilities are filled in, creating continuous variation, rather than distinct types.

Front 32

32. Explain how two parents that are 5’ 8” tall could have a child who grew to 6’ 2” tall, even if
the environments in which they were raised, their medical care, etc. were all the same. Provide an explanation that routinely occurs in real life, not an extremely unlikely mutation.

Back 32

Height is a polygenic trait (OR is controlled by numerous loci OR alleles OR genes) Each parent has a mix of alleles (OR genes), some contributing to tallness, others to shortness, resulting in their medium height. By chance, the offspring could get mostly the alleles (OR genes) that contribute to tallness from each parent, resulting in a genotype with more alleles for tallness than in either parent.

Front 33

33. What is a point mutation, and what changes can it cause?

Back 33

A point mutation is a change (OR error) in a single nucleotide base in a copy of DNA created by
replication. OR an error in which a single base gets copied incorrectly during DNA replication.
If the change is in a segment of “junk” DNA, it has no effect. If it is in a gene, it may still have
no effect if it changes a codon to a different one for the same amino acid. If the change alters a
codon to one for a different amino acid, it changes one amino acid in the primary structure of
the protein produced by the gene. This may affect the protein’s function to any degree from not at all to very severely. If the change creates a “start” or “stop” codon, the allele produces a truncated protein, usually affecting its function drastically. Most changes are neutral or for the worse, but in rare cases, the altered protein functions better or performs a new, useful function.

Front 34

34. Define evolution in population genetic terms.

Back 34

Evolution is a change in allele frequencies in a population from one generation to the next (OR across generations, etc.)

Front 35

35. Being homozygous for the recessive h allele results in hitchhiker’s thumb; having the
dominant S allele produces straight thumbs. These are the only two alleles at this locus. Say
that in the whole population, the frequency of h alleles is 80%.
a. What is the frequency of S alleles?
b. Say we observe a population of 500 males and 500 females (1000 people total). They all form couples and have kids. Assuming that having hitchhiker’s thumbs or straight thumbs has no effect on survival or reproduction, what are the frequencies of each possible genotype among the offspring? Explain with a Punnett square.
c. Say each couple has two offspring, for a total of 1000 kids. About how many of them would you expect to have straight thumbs?

Back 35

a. 20% (Because 80% + 20% = 100%)
b. S=20% h=80% (just times them together)
c. About 360 are expected to have straight thumbs. Straight thumbed people have genotype SS or Sh (or hS, which is the same). In the Punnett square above, we see that 4% of the offspring should be SS, 16% should be Sh, and 16% should be hS . So the number of straight-thumbed individuals in the population of 1000 should be 1000 x (0.04+0.16+0.16) = 360.