Exam 1 PPTs - 3

Question 1

In nature, there is a struggle for …

• cod produce far more eggs than are needed to … the population
• about …% die in the first month of life
• from the surviving, …% won’t reach the age of 1

Answer 1

existence;
propagate;
99;
90

Question 2

Darwin’s observations:
“The elephant is reckoned the … of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase; it will be safest to assume it begins breeding when thirty years old, and goes on breeding until 90, bringing forth 6 young in the interval, and surviving till 100 yo; if this be so, after a period of 740 to 750 ys, there would be nearly … elephants alive, descended from the first pair.”

Answer 2

slowest breeder;

19 million

Question 3

… results in competition, to survive and reproduce:

• in elephants, as in cod, many individuals … between egg and adult
• the world contains only limited amounts of … and …
• as resources are used up, the … in the population increases, and when the death rate equals the birth rate, the population will …

Answer 3

excess fecundity; 
die; 
food; space; 
death rate; 
stop growing

Question 4

Excess fecundity results in competition, to survive and reproduce:
- organisms compete to survive and reproduce - both directly, for example by …, and indirectly, for example by eating food that could otherwise be …

Answer 4

defending territories;

eaten by another individual

Question 5

Excess fecundity results in competition, to survive and reproduce:
- the expression … is metaphorical: it does not imply a … to survive, though fights do sometimes happen

Answer 5

struggle for existence;

physical fight

Question 6

Natural selection operates if some conditions are met:

1. …: entities must … to form a new generation
2. …: the offspring must tend to …

Answer 6

reproduction;
reproduce;
heredity;
resemble their parent

Question 7

Natural selection operates if some conditions are met:
3. variation in … among the members of the population
4. variation in the … of organisms according to the state they have for a heritable character
higher fitness –> more likely to … than other members of the species

Answer 7

individual characters;
fitness;
reproduce

Question 8

HIV illustrates the logical argument:

• it reproduces by having a … copy made of its …
• most of the reproductive process is performed by … supplied by the host cell

Answer 8

DNA;
RNA;
enzymes

Question 9

HIV illustrates the logical argument:

• The virus supplies the … that makes the DNA from RNA
• If this enzyme can be inactivated by a drug, the virus is …

Answer 9

reverse transcriptase;

stopped from reproducing

Question 10

HIV illustrates the logical argument:

• The drug 3TC is a molecule similar to the nucleotide …
• the reverse transcriptase of drug-susceptible HIV will incorporate … instead of … into a growing DNA chain
• the 3TC then …, and thus prevents the HIV from …

Answer 10

cytosine; 
3TC; 
C; 
inhibits future reproduction; 
copying itself

Question 11

HIV illustrates the logical argument:

• What happens when an individual infected with HIV takes 3TC? Initially the HIV population in the human body …
• Within days, … strains of HIV start to be detected. Those strains then …

Answer 11

decreases by a huge amount;
3TC-resistant;
increase in frequency

Question 12

HIV illustrates the logical argument:

• Drug-resistant strain increases to … of the viral population in the patient’s body
• this is evolution of … by …

Answer 12

100%;
drug resistance;
natural selection

Question 13

HIV illustrates the logical argument:

• 3TC-resistant HIV has mutation in one codon in the gene that codes for …
• 3TC-resistant version of HIV has …
• in the presence of the drug it is adaptive for HIV to reproduce … but …

Answer 13

reverse transcriptase;
slower reproduction;
slowly; carefully

Question 14

HIV illustrates the logical argument:

• in the absence of the drug it is adaptive to …
• it is at a … when the drug is not present

Answer 14

reproduce faster;

disadvantage

Question 15

Natural selection can be:

• …
• …
• …

Answer 15

directional;
stabilizing;
disruptive

Question 16

look at graphs in ppt

Answer 16

ok

Question 17

stabilizing selection:

- infants weighing … at birth have a higher survival rate

Answer 17

8 lb

Question 18

… of selection can occur

Answer 18

relaxation

Question 19

Variations in natural populations is widespread:
How much and with respect to what characters do natural populations show variation, and in particular, variation in fitness?

• … level: the individuals of a natural population vary for almost any character we may measure: … variation or … character, … variation

Answer 19

morphological;
continuous;
continuous;
categorical

Question 20

variation in natural populations can also be at the … level and at the … level

Answer 20

cellular;

biochemical

Question 21

Variations in natural populations is widespread:

• biochemical level: …
  e. g. electrophoresis of tissue extracts from 15 different green treefrogs reveals 4 allelic versions of the enzyme …

Answer 21

protein polymorphism;

aconitase

Question 22

Variations in natural populations is widespread:

can also be at the … level

Answer 22

DNA

Question 23

organisms in a population vary in …

- for natural selection to work, variation in a character must be associated with …

Answer 23

reproductive success;

reproductive success

Question 24

new variation is generated by … and …

- the variation that exists in a population is the resource on which …

Answer 24

mutation;
recombination;
natural selection works

Question 25

Variation created by recombination and mutation is random with respect to the …

• direction of evolution is uncoupled from the direction of …
• when a new recombinant or mutant genotype arises, there is no tendency for it to arise in the direction of …

Answer 25

direction of adaptation;
variation;
improved adaptation