Exam 1 PPTs - 3 Flashcards
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
existence;
propagate;
99;
90
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.”
slowest breeder;
19 million
… 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 …
excess fecundity; die; food; space; death rate; stop growing
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 …
defending territories;
eaten by another individual
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
struggle for existence;
physical fight
Natural selection operates if some conditions are met:
- …: entities must … to form a new generation
- …: the offspring must tend to …
reproduction;
reproduce;
heredity;
resemble their parent
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
individual characters;
fitness;
reproduce
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
DNA;
RNA;
enzymes
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 …
reverse transcriptase;
stopped from reproducing
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 …
cytosine; 3TC; C; inhibits future reproduction; copying itself
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 …
decreases by a huge amount;
3TC-resistant;
increase in frequency
HIV illustrates the logical argument:
- Drug-resistant strain increases to … of the viral population in the patient’s body
- this is evolution of … by …
100%;
drug resistance;
natural selection
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 …
reverse transcriptase;
slower reproduction;
slowly; carefully
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
reproduce faster;
disadvantage
Natural selection can be:
- …
- …
- …
directional;
stabilizing;
disruptive
look at graphs in ppt
ok
stabilizing selection:
- infants weighing … at birth have a higher survival rate
8 lb
… of selection can occur
relaxation
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
morphological;
continuous;
continuous;
categorical
variation in natural populations can also be at the … level and at the … level
cellular;
biochemical
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 …
protein polymorphism;
aconitase
Variations in natural populations is widespread:
can also be at the … level
DNA
organisms in a population vary in …
- for natural selection to work, variation in a character must be associated with …
reproductive success;
reproductive success
new variation is generated by … and …
- the variation that exists in a population is the resource on which …
mutation;
recombination;
natural selection works
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 …
direction of adaptation;
variation;
improved adaptation
