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General Biology 2 Exam 1 at PCC


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In many insects, wing mutations which prevent flight are selected against. In 4 of the environments below, this would be true, but one environment would select FOR the flightless condition. Which one?

A) An island with strong winds that blow s
E) A cage with slippery walls that prevent climbing, & an electrified bug-zapper at the top which kills insects on contact
Which of the following did Darwin NOT understand about natural selection?

A) Variation is common in a population

B) The source of that variation

C) Competition exists in populations

D) Populations overproduce o
B) The source of that variation
The gene pool can best be described as the

A) Genes found only in isolated populations

B) Group of genes responsible for polygenic traits

C) Total number of gene loci that occur in each species

D) Total aggreg
D) Total aggregate of genes in a population at any given time
Which of the following is/are likely to have been produced by sexual selection?

A) Different sizes of male & female cones in pines

B) Bright colors in female flowers

C) Male lion's mane

D) A, B, and C
C) Male lion's mane
Most copies of harmful recessive alleles in a population are carried by individuals that are

A) Heterozygous

B) Homozygous

C) Polyploidy

D) Haploid

E) Polymorphic
A) Heterozygous
An African butterfly species exists in 2 striking different color patterns, each of which resembles other species distasteful to birds

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection<
C) Diversifying (disruptive) selection
Peacocks with more eyes in their tails mate more often than those with fewer eyes

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection

D) Stabilizing selection

E) Sex
E) Sexual Selection
Most Swiss starlings produce 4-5 young in each clutch

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection

D) Stabilizing selection

E) Sexual selection
D) Stabilizing selection
Pathogenic bacteria in many hospitals are antibiotic resistant

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection

D) Stabilizing selection

E) Sexual selection
B) Directional selection
In a species of snail, cream & brown morphs are common, while intermediate coloration is relatively rare

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection

D) Stabilizing
C) Diversifying (disruptive) selection
From the fossil evidence, it appears that horses have increased in size over time

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection

D) Stabilizing selection

E) Sex
B) Directional selection
The average birth weight for humans is 7 pounds

A) A random selection

B) Directional selection

C) Diversifying (disruptive) selection

D) Stabilizing selection

E) Sexual selection
D) Stabilizing selection
When we say that 1 organism has greater fitness than another, we specifically mean that it

A) Lives longer than others of its species

B) Competes for resources more successfully than others in its species

C) Mates more fr
D) Leaves more viable offspring than others of its species
What evidence supports the idea that the earth has had a rich & varied fauna & flora?
Fossil record
Define evolution by natural selection as a biologist would. Then, explain to a 12 year old what evolution is.
Biologist explaination:

Evolution occurs when natural selection causes changes in relative frequencies of alleles in the gene pool.

12yr old explaination:

organisms that are better for surviving will survive
Darwin proposed his theory of evolution by natural selection based on several observations & inferences. Name 2 of these.
- similiar adaptations in different parts of the world

- Beetles around the world differ

- Overproduction of offspring

- Finches on some islands were better capable of surviving

- species similarities and differences

- gradualism

- competition
Why was the work of Miller(/Urey) important to the work of Orgle & Fox? What is the importance of experiments by these men?
The work of Miller(/Urey) helped lead Orgle & Fox to discovering how the genetic system could have originated.

The experiments of these men are important because they show us the steps in the rise from an abiotic world to the cell.
What are the assumptions of the Hardy-Weinberg equillibrium model?
> Large population

> No gene flow

> Random mating

> No mutation (net)

> No natural selection (stable environment)
Name 3 ways in which all cells are ALIKE.
-genetic material


-cell membrane

-use ATB

-repoduce by some mechanism
What is the unit of evolution?
In a population that is in H-W equilibrium, the frequency of an allele (1 of 2 morphs) is 0.3. What % of the population is heterozygotic for this gene?

2*(freq 1 allele)(freq 2 allele)


Briefly characterize the 3 domains of life.
Archaea> all prokaryotic and live in extreme environments

Eukarya> true nucleus, prokaryotes, eukaryotic cells

Bacteria> unicellular, prokaryotes, live in extreme environments
In a population of 1000, 160 have AA blood type, 480 are AB and 360 are BB.

a) What are the frequencies of A and B?

b) What percent of the population is type O?

c) If 4000 children are produced by this generation, how man
a) A=(160/1000)=sqrt(0.16)=0.4


b) There are no individuals that carry the O allele.

c) 480(# of children for one thansound yrs) * 4(thousands of yrs) = 1920 type AB children
What are the sources of variation within a population? (list 3)

Crossing over

Independent assorment of chromosomes

Random fertilization
Place these events in the most likely sequence (earlier -> later) of when they appear to have happened on Earth

A) appearance of photosynthesis

B) first cells

C) multicellular organisms

D) eukaryotic cells

(F and A possible at same time)
Would the biological species concept be applicable to an asexual species?
No, because there is no interbreeding
Compare & contrast allopatric & sympatric speciation.
Ways similiar:

- Both result in ability to interbreed

- They result in 2 species other than one

Ways different:

- In allopatric speciation, a new species forms while geographically isolated from its parent population.

- In sympatric speciation, a reproductive barrier isolates a subset of a population without geographic separation.
Compare & contrast polyphyletic classification with monophyletic classification.
Similiar: both attempt to explain the relationships of organisms


- Monophyletic consists of grouping the ancestral species and all its descendants.

- Polyphyletic consists of grouping several species that lack a common ancestor.
How would you respond to the statement that mutation must be nonrandom- look at the results (e.g., sickle cell)?
-> Mutations are always random

-> Mutations produce errors in genetic code

-> Mutations occur spontanously
Similarity in characteristics resulting from a shared ancestry.
Similarity between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait.
(plural, taxa)

The named taxanomic unit at any given level of classification.
A localized group of individuals that belong to the same biological species (that are capable of interbreeding and producing fertile offspring).
bottleneck effect
Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.
founder effect
Genetic drift that occurs when a few individuals become isolated from a larger population, with the result that the new populations gene pool is not reflective of the original population.
geographic variation
Differences between the gene pools of seperate populations or population subgroups.
Darwinian fitness
The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals.
relative fitness
The contribution of one genotype to the next generation compared to that of alternative.
neutral variation
Genetic diversity that confers no apparent selective advantage.
A chromosomal alteration in which the organism possesses more than two complete chromosome sets.
Evolutionary change below the species level; change in the genetic makeup of a population from generation to generation.
Evolutionary change above the species level, including the appearance of major evolutionary developments, such as flight, that we use to define higher taxa.
maximum parsimony
A priciple that follows we should first investigate the simplest explanation that is consistent with facts.
The analytical study of the diversity and relationships of organisms, both present-day and extinct.
molecular clock
An evolutionary timing method bases on the observation that at least some regions of genomes evolve at constant rates.
reproductive isolation
The existence of biological factors (barriers) that impede members of two species from producing viable, fertile hybrids.
Pertaining to a grouping of species consisting of an ancestral species and all its descendents; a clade.
Pertaining to a grouping of species derived from two or more different ancestral forms.
Pertaining to a grouping of species that consists of an ancestral species and some, but not all, of its descendents.

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