exam 4

Question 1

How many pairs of chromosomes do we have

Answer 1

23; 22 are autosomes and 1 are sex chromosomes

Question 2

incomplete dominance

Answer 2

A form of inheritance in which heterozygotes have a phenotype that is intermediate between homozygous dominant and homozygous recessive- mixture- example purple flower

Question 3

co-dominance

Answer 3

Both maternal and paternal alleles contribute equally and separately to the phenotype. Ex cow spots or red and blue flower

Question 4

Poly-genic trait

Answer 4

Trait that is controlled by multiple genes. Ex: height or skin color

Question 5

Multi-factorial trait

Answer 5

trait that is controlled by multiple genes and environmental factors. Ex: height again, stress and mental development

Question 6

MRSA

Answer 6

-Methicillin-resistant Staphylococcus aureus
-Infectious bacterium
* Difficult to treat with antibiotics
* Kills 19,000 people in the United States each year
-Developed resistance to antibiotic drugs*
- Adversely affects people with weakened immune system

Question 7

antibiotics

Answer 7

chemicals that either kill bacteria or affect their growth.* Interfere with function of essential bacterial cell structures, e.g. beta-lactams that degrade cell wall

Question 8

antibiotic resistance

Answer 8

-Some bacteria can survive antibiotics
* Acquire random mutations when DNA replicates during asexual reproduction
-Random genetic changes ultimately altered bacterial proteins in ways that helped staph dodge antibiotic drugs.
* Altered or acquired genes code for proteins that can:
* disable antibiotics, or
* code for membrane proteins with altered shapes to which antibiotics can no longer bind.

Question 9

binary fission

Answer 9

One single parental cell into two daughter cells-mutation replicated and passed down

Question 10

evolution

Answer 10

change in allele frequencies over time

Question 11

how populations evolve

Answer 11

-Fitness: organisms’ ability to survive and reproduce in a particular environment
-Interplay between phenotype and environment determine frequency of traits in a population
* If traits improve fitness, traits become more common in population
* Population evolves by natural selection

Question 12

4 conditions needed for a population to evolve

Answer 12

1. The trait is heritable.
2. Genetic variation in the trait within the population.
3. Variation in fitness within the population.
4. Individual fitness varies depending on the trait.

Question 13

natural selection

Answer 13

differential survival and reproduction of individuals within a population in response to environmental pressure
-Advantageous traits become more common and population becomes better suited, or adapted, to environment

Question 14

direction selection

Answer 14

Favor only one extreme: Ex; lizards go from short tails to long tails bc they look like snakes

Question 15

Stabilizing selection

Answer 15

favors the medium from one extreme to another. Ex; Tigers get medium sized tails

Question 16

disruptive selection

Answer 16

Does not favor the medium at all. Ex: Light- and dark-colored oysters could also have a camouflage advantage as opposed to their medium-colored relatives.

Question 17

Sextual selection

Answer 17

variation, heritability, variation in reproductive success, trait confers altered reproductive success

Question 18

individuals with different phenotypes

Answer 18

will have differing abilities to survive and reproduce in a population; that is, they will differ in fitness.

Question 19

scientific theory

Answer 19

statement providing the current best explanation of how the universe works
–Supported by many lines of evidence
–Withstands repeated experimental tests

Question 20

microevolution

Answer 20

changes that occur within a biological population.
mosquitoes evolving resistance to DDT.

Question 21

gene flow

Answer 21

interbreeding between population- less diversity-non adaptive

Question 22

genetic drift

Answer 22

Random occurrence that causes changes within a population- went from a lot of diversity to less

Question 23

where did modern humans originate

Answer 23

africa

Question 24

founder effect

Answer 24

type of genetic drift
a subset moves on to a different area forming a new population
Over time, the resulting new subpopulation will have genotypes and physical traits resembling the initial small, separated group, and these may be very different from the original larger population.

Question 25

how to increase genetic diversity

Answer 25

Mutation: –random changes to nucleotide sequences
* Gene flow: –movement of alleles from one population to another

Question 26

Mechanical isolation

Answer 26

pre-zygote: Mating organs incompatible

Question 27

Gametic isolation

Answer 27

pre-zygote: gametes cannot unite

Question 28

• Hybrid inviability

Answer 28

Post-zygote: Gametes unite but offspring not viable- die after fertilization

Question 29

Hybrid infertility

Answer 29

Post-zygote: Offspring cannot produce

Question 30

speciation

Answer 30

Genetic divergence of populations, leading over time to reproductive isolation and the formation of new species

Question 31

macroevolution

Answer 31

large-scale evolutionary changes that result in the origin of new species

Question 32

lactose intolerance

Answer 32

stems from famine

Question 33

Melanin

Answer 33

Pro: protects from sun… Con: can cause vitamin D deficiency

Question 34

vestigial structure

Answer 34

Once served a purpose. Ex; tailbones

Question 35

developmental homology

Answer 35

tells us that we shared a common ancestor by relating different fetus forms from different organisms

Question 36

interbreeding depression

Answer 36

negative reproduction consequences- almost caused Florida panther to go extinct

Question 37

convergent evolution

Answer 37

organisms that are geographically separate form similar adaptations. Ex flying squirrel and sugar glider