bio semester study guide

Juncos are birds that normally live in mountainous forests and have white outer tail feathers. Males with whiter (40-45%) tails are more likely to attract females and win aggressive interactions.

A group of juncos became established on the UCSD campus in 1983. However, their tails averaged only 36% white.  This difference is most likely due to ________. 

the founder effect

In what way were both Lamarck's and Darwin's  theories in complete agreement?

Gradual change explains why organisms are well-suited to their environments.

Many properties of living things involve the transfer and transformation of energy and matter. For example, plant chloroplasts convert energy from sunlight to which of the following forms of energy or matter?

chemical energy

Soon after the island of Hawaii rose above the sea surface (about one million years ago), the evolution of life on this new island should have been most strongly influenced by  ________.

the founder effect

The maggot fly is an example of how introduction of a new ____ can result in speciation.

niche

A _____ point is where two species diverge from a common ancestor.

branch

An earthquake decimates a ground-squirrel population, killing 98% of them. The surviving population happens to have broader stripes compared to the initial population. If stripe patterns are genetically determined, what effect has the ground-squirrel population experienced during the earthquake? 

the bottleneck effect

Why is the amniotic egg considered an important evolutionary breakthrough?

It allows deposition of eggs in a terrestrial environment.

____ are organisms that are bipedal and always walk with two feet.

hominins

____ build proteins and are required for every living organism.

ribosomes

According to scientists' hypotheses, prokaryotes most likely evolved prior to eukaryotes because

prokaryotes are the simplest organisms on the planet.

____ studies the changing allele frequencies of populations over time.  (Be specific as answer with your terminology)

microevolution

Mutations are usually rare.

true

Fossils found in strata reveal that ________.

older strata carry contain older fossils

_____ is the supercontinent that separated due to continental drift.

pangea

_____ occurs in plants when they have more than two full sets of DNA.

polyploidy

Which of the following attributes is common to both prokaryotic cells and eukaryotic cells?

the use of a cell membrane

Which of the following terms describes membrane-enclosed components of cells that carry out specialized functions?

organelles

Within two years of using methicillin to treat S. aureus infections, all new S. aureus infections were caused by MRSA. How can this best be explained?

Natural selection selected for drug-resistant bacteria were present at the start of treatment.

Which of the following is the most predictable outcome of increased gene flow between two  populations?

decreased genetic difference between the two populations

Which of the following statements describing hominin evolution is correct?

Homo sapiens is the only surviving member of a highly branched tree of hominin species.

What is thought to be the correct sequence of these events, from earliest to most recent, in the  evolution of life on Earth?

1. origin of mitochondria 

2. origin of multicellular eukaryotes 

3. origin of chloroplasts 

4. origin of cyanobacteria 

4, 3, 1, 2

How was early Earth (more than 3 bya) different from today's Earth?

Early Earth had an anaerobic atmosphere rich in gases from volcanic eruptions.

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species.  Recently, these birds have been classified as a single species. Which of the following would be the cause for  this reclassification? 

The two forms interbreed, and their offspring survive and reproduce well.

wo populations of flightless birds with somewhat different coloration live on different islands. When birds from the two populations are brought together, they produce young whose appearance is intermediate  between the two parents. These offspring can breed with each other or with either parent population.

What keeps the two populations separate? 

habitat isolation

Which of the following characteristics are expected in the first animals to have colonized  land?

I) They were probably herbivores (ate photosynthesizers).

II) Animals had two appendages.

III) Animals had the ability to resist dehydration.

IV) Invertebrates

V) They were still reliant on being close to water.

I, III and V

What phrase did Darwin coin that explained his understanding of natural selection and evolution?

descent with modification

Which of the following traits is not used to differentiate humans from our closest living primate relatives?

opposable thumbs

How would strengthening reproductive barriers in a hybrid zone affect the group of hybrids?

it would cause the number of hybrids to decrease over time

Mammals are _____ because they can regulate their own body temperature

endothermic

Within the past century, humans have been eating higher cholesterol and fatty meals and have become less physically active, which makes them more susceptible to heart disease. Which of the following will lead to an adaptation?

Some people's bodies are able to break down cholesterol and fat more efficiently than others.

As geographic distance between two populations decreases, the degree of reproductive isolation increases.

False

Long periods of environmental stability increase speciation.

false

Which of these conditions are always true of populations evolving due to natural selection? 

Condition 1: The population must vary in traits that are heritable. 

Condition 2: Some heritable traits must increase reproductive success. 

Condition 3: Individuals pass on most traits that they acquire during their lifetime. 

Conditions 1 and 2

Which of these characteristics is shared by algae and seed plants?

photosynthesis

Genetic variation ________

is increased in a population due to sexual reproduction.

Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but  crabs have reduced tails that curl under their shells and are not used in swimming. This is an  example of ________. 

a vestigial trait

Which postzygotic barriers prevent formation of hybrids beyond the first generations?

hybrid breakdown

Individuals that inherit two sickle-cell alleles (mutations in the hemoglobin gene) are selected against because mortality. However,  those with only one sickle-cell allele experience very few negative effects and are more likely to survive malaria. How would this affect areas where malaria is endemic?

sickle-cell allele frequency would increase

Rocky Mountain juniper and one-seeded juniper are two species with overlapping ranges. Pollen (sperm) from one species are unable to fertilize female egg of the other  species. These two juniper species are kept separate by ________.

gametic isolation

After the drought of 1977 on the Galapagos Islands, researchers hypothesized that finches with large, deep beaks survived better than those with smaller  beaks because they could more easily crack and eat tough seeds. Since then, a tourist  company has set up feeding stations with a variety of bird seeds (different types and sizes)  so that tourists can get a better look at the finches. Which of these events is now most likely to  occur to finch beaks on this island? 

increased variation in beak size and shape over time

Rank the following in order from most general to most specific. 

1. gametic isolation 

2. reproductive isolating mechanism 

3. sperm-egg incompatibility in sea urchins 

4. prezygotic isolating mechanism 

2, 4, 1, 3

Where would you expect to find the largest number of endemic species which have existed for at least a few million years?

an isolated ocean island in the tropics

How does continental drift explain the uniqueness of Australian animals?

Marsupials are endemic to Australia because they evolved after the breakup of Pangea

Comparisons of Neanderthal DNA revealed that there are more similarities to non-African DNA compared to those from Africa. Additionally, scientists found that  Neanderthal DNA is as closely related to East Asians as to Europeans. This indicates that interbreeding occurred before human migration further east. What process of population genetics generated these results?

gene flow

_____ structures are those that have similar structures, but different functions that arose through divergent evolution.

homologous

Which of the following factors could cause a surge in population size?

better eyesight evolves in the population

Fishes called cichlids prey on large algae-eating fish using their eyesight.  In other words, cichlids rely on their eyesight to eat the algae-eaters. Which of the following would decrease survival of the cichlids?

selection for better camoflauge of the algae-eaters

_____ is the movement of individuals out of a population.

emigration

Which of the following is not an accurate statement regarding human evolution?

Once bipedality, tool use, and larger brains evolved in humans, humans stopped evolving.

Two species of frogs belonging to the same genus occasionally mate, but the embryos stop  developing after a day and then die. These two frog species are kept separate by ________.

reduced hybrid viability

According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that ________. 

speciation occurred rapidly

Write the chemical equation for cellular respiration.

C6H12O6 +6 O2 ——>6 CO2+ 6 H2O + chemical energy

An article in the New York Times stated the following: "Scientists have discovered micro-organisms living beneath the ocean floor that appear to have not evolved for more than two billion years, a finding that may support the theory of evolution." The lack of evolution of these microorganisms could be caused by

the bacteria's unchanging environment.

Challenges for survival of the first land plants include

I. sources of water.
II. sperm transfer.
III. desiccation.
IV. animal predation.
V. lack of roots.

I, II, III and V

Arrange the following in order from most general to most specific. 

1 natural selection 

2. microevolution 

3. intrasexual selection 

4. evolution 

5. sexual selection 

4, 2, 1, 5, 3

Which of the following statements best explains why changes made during the lifetime of an individual are not inherited?

Characteristics acquired during an organism's life are not passed on through genes.

Given a population that contains genetic variation, what is the correct sequence of the  following events under the influence of natural selection?  1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. The number of beneficial traits increases. 4. Poorly adapted individuals have decreased survivorship.

2 → 4 → 1 → 3

Why are fossils considered to be an incomplete record of evolution?

The fossil record is biased for organisms that had hard shells and skeletons.

Which of the following is likely the greatest impact that organisms have ever had on Earth?

Early cyanobacteria released oxygen to Earth's atmosphere during photosynthesis.

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid 1700s. They do not marry with members outside their own immediate community. Today, the  Dunkers are genetically unique and differ in gene frequencies compared to everyone else. Which of the following mechanisms  likely explains the genetic uniqueness of this population?

the founder effect and genetic drift

A group of small fish live in a lake with a light-brown sandy bottom. Most of the fish are light brown, but about 10% are darkly colored. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a darker appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?

The proportion of darker fish will increase over time.

_____ carries glucose throughout vascular plants.

phloem

Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in  both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but  small depressions on the front of its skull suggest it had whiskers and, therefore, fur.  Thrinaxodon may have been warm-blooded. The fossils of Thrinaxodon are consistent with the  hypothesis that ________. 

mammals evolved from a reptilian ancestor

Successful hybrids can form new species.

true

The _____ was an infinitely dense/hot cluster of all the matter and energy in the universe.

singularity

The earliest ancestors of about half of all extant animal phyla can be traced back to the __________ explosion.

Cambrian

If the half-life of an unstable isotope is 10,000 years, and only 1/8 of the radioactive parent remains in a sample, how old is the sample?

30,000 years old

The purpose of vascular tissue allowed plants to

absorb nutrients and water from below-ground tissues to above-ground tissues and grow taller

Which of the following did NOT occur during the evolution of the genus Homo?

teeth got sharper and larger

Both birds and mammals shared a common ancestor that was terrestrial. Today, penguins (birds) and seals (mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?

homologous; analogous

_____ is a strain of bacteria that has become resistant to antibiotics over time.

MRSA

No two people are genetically identical, except for identical twins. The main source of genetic  variation among humans is 

sexual reproduction.

Which of the following describes the most likely order of events in allopatric speciation?

genetic isolation, genetic drift, speciation

Many songbirds breed in the summer, and then migrate South in the fall. Here they enjoy warmer weather, feed and prepare for the spring migration north.

Two hypothetical species of sparrow, A and B, spend winter together (in mixed flocks) in Costa Rica. In spring, species A goes to the northeast, and species B goes to the northwest. What can you say about the isolating mechanisms of these two species?

They don't interbreed because they are isolated by their habitats during mating season.

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more  antibiotic-resistance genes, what would happen in environments that lack antibiotics?

These bacteria would be outcompeted and replaced by bacteria that have lost these genes.

The oxygen revolution changed Earth's environment dramatically. Which of the following  took advantage of the presence of oxygen in the oceans and atmosphere?

the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules

A species of cow bred for meat and milk (Bos primigenius) has a smaller brain and larger eyes than closely related wild species of ungulates. These traits most likely arose by ________.

artificial selection, because of human selection for high milk and muscle content

____were the very first eukaryotic organisms

protists

BONUS:  How many molecules of water are required to break down a protein that is 10 amino acids long?

9

Fats and phospholipids both contain

a glycerol

Which polysaccharide is an important component in fungi?*

chitin

Which of the following statements about the 5' end of a strand of RNA is  correct?

The 5 end has a phosphate group attached to the number 5 carbon of ribose

Acidic amino acids are nonpolar.

False

How do phospholipids interact with water molecules?

The polar heads interact with water; the nonpolar tails do not

Which of the following polysaccharides is not composed of glucose monomers?

chitin

Which of the following is true of unsaturated fats?

They are more common in plants than in animals.

Which of the following statements is true regarding lipids?

Phospholipids are both hydrophilic and hydrophobic.

A glycosidic linkage is analogous to which of the following in lipids?

ester linkage

Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules because they  ________.

do not have a polar or charged regions

Which of the following best describes nucleotides?

a nitrogenous base, a sugar and a phosphate group

_____ bridges (within proteins in your hair) are responsible for its overall shape and structure.

disulfide

Identify the following molecule:  peptide/protein.

1/1

D

In a single strand of RNA,

the number of guanine and cytosine nucleotides will not necessarily be the same.

Identify the following molecule:  disaccharide.

1/1

A

Identify three functional groups discussed in class.*

3/3

carboxyl, amino, ketone

Identify the following molecule:  saturated phospholipid.

1/1

I

BONUS:  If a strand of DNA contains 28% thymine, what percentage of the DNA would be cytosine?  Hint:  Think about the complementary nature of DNA.

22

When nucleotides polymerize to form a nucleic acid, ________.*

a covalent bond forms between the sugar of one nucleotide and the phosphate of a second

Identify the following molecule:  thymine.

1/1

P