Lecture 20 Vocab and Prereading

Question 1

adaptation

Answer 1

a trait that enhances the fitness of an organism to its environment;

Question 2

artificial selection

Answer 2

a form of directional selection similar to natural selection (breeding dogs to get specific physical trait

Question 3

allele frequency

Answer 3

proportion of a specified allele among all the alleles of a gene in a population

Question 4

allele fixation

Answer 4

when over generations, one allele of a gene becomes the only ones present in a population

Question 5

allele loss

Answer 5

when a particular allele becomes less common in a population over time

Question 6

balancing natural selection

Answer 6

natural selection that acts to maintain two or more alleles of a given gene in a population

eg: *a bunny with long ears can hear predator better
*bunny w short ears can move through bushes quicker to get away from predators

Question 7

continuous (polygenic) traits

Answer 7

characteristic that varies across a tangle and is controlled by multiple genes

eg: height(it varies and many genes come together to influence how tall someone is

Question 8

discrete trait

Answer 8

characteristics that have distinct separate options
*traits controlled by just one or a few genes
eg: that doll has blonde hair, that doll has red

Question 9

directional natural selection

Answer 9

“nature pushing things in a certain direction based on what works better in the environment

eg: birds in forest have huge beaks and small ones. change in environment occurs causing bigger seeds and it’s easier for bigger beaks to eat the seeds

Question 10

disruptive natural selection

Answer 10

when nature favors both extreme traits

eg: brown rabbit and white rabbit
white rabbit can hide in snow brown rabbit can hide in brown bushes

Question 11

evolution

Answer 11

theory of how all living things are related in some way

Question 12

fitness

Answer 12

how well living this so in terms of survival and reproduction

eg: very fast cheetah, can find food quickly, naturally stronger than others,
(how these traits will pass down to their offspring)

Question 13

gene interaction

Answer 13

how different genes team up and work together to create the traits we see in living things

Question 14

environment interaction

Answer 14

how surroundings of environment can influence and shape the traits or characteristics of living things

Question 15

heterozygote advantage

Answer 15

where individuals with two different versions (alleles) of a particular gene have a better chance of survival or reproductive success compared to individuals with two identical alleles (homozygotes)

Question 16

natural selection

Question 17

polygenic(quantitative) inheritance

Question 18

polymorphism

Question 19

positive selection

Question 20

relative fitness

Question 21

negative selection

Question 22

stabilizing natural selection is

Answer 22

nature favoring the average or middle traits because they seem to work well and help the organisms survive and have babies

Question 23

example of heterozygote advantage

Answer 23

sickle cell anemia-

if you have two copies of the normal allele (AA) you’re at risk for malaria. But if you have two copies of the sickle cell(aa) your might have sickle cell. Being heterozygote and having Aa gives you a better advantage if surviving malaria without getting sickle cell anemia

Question 24

natural selection changes

Answer 24

allele frequencies

Question 25

positive selection increases the frequency of

Answer 25

beneficial alleles

Question 26

negative selection decreases the frequency of

Answer 26

deleterious alleles

Question 27

natural selection increases the frequency of

Answer 27

advantageous mutations

Question 28

natural selection decreases the frequency

Answer 28

of deleterious mutations

Question 29

when a allele is fixed what’s the frequency?

Answer 29

1

Question 30

when an allele is lost or eliminated the frequency is

Answer 30

0

Question 31

directional selection can be applied to

Answer 31

discrete or polygenic traits l

Question 32

stabilizing and disruptive selection only applies to

Answer 32

polygenic traits
(show a continuous distribution within a population)