B17 - variation & selection

Question 1

types of variation

Answer 1

-continuous - has a spread
-discontinuous - boolean

Question 2

causes of discontinuous variation

Answer 2

-controlled by 1 pair of genes

Question 3

causes of continuous variation

Answer 3

-controlled by more than 1 pair of genes
-environment

Question 4

examples of continuous variation

Answer 4

-height
-skin colour

Question 5

examples of discontinuous variation

Answer 5

-blood groups
-attached or detached earlobes
-tongue rolling
-eye colour

Question 6

description of continuous variation

Answer 6

-range of phenotypes btw 2 extremes *
-no distinct categories
-many intermediates
(use of frequency histogram without gaps)

Question 7

description of discontinuous variation

Answer 7

-limited no. of phenotypes
-with no intermediates *
(uses a bar chart with gaps)

Question 8

inherited features example

Answer 8

-eye colour
-tongue rolling

Question 9

environmental features

Answer 9

-muscles
-scars

Question 10

inherited features affected by environment

Answer 10

-skin colour

Question 11

which graph is used for which variation

Answer 11

continuous - frequency histogram with no gaps - has line of normal distribution
discontinuous - bar chart with gaps

Question 12

define variation

Answer 12

differences btw individuals of the same species

Question 13

causes of variation & examples

Answer 13

-genes - eye colour, blood type, tongue rolling
-environment - sun burnt, scars, accent

Question 14

define mutation & example

Answer 14

-a genetic change to the DNA in a gene or chromo.
-cystic fibrosus, Albinism, hemophilia
-same genes, diff alleles

Question 15

result of mutation

Answer 15

-new alleles are formed because mutation changes the sequence of DNA bases which result in diff. protein being coded for

Question 16

define artificial selection

Answer 16

-choosing particular organisms with desired characteristics to breed tgt & continuing this process over many generations

Question 17

process of artificial selection

Answer 17

-select organism with desirable features
-cross them with each other to make the next gen.
-select offspring with desirable characteristics and cross them
-continue this over many generations
-desirable features become more & more common until all offspring has the features

Question 18

reasons for artificial selection for corn

Answer 18

-larger cob
-larger kernel (seed)
-juicier kernel
-resistant to diseases

Question 19

reasons for artificial selection for pigs

Answer 19

-larger
-non hair
-no tusks
-resistant to diseases

Question 20

stages for natural selection

Answer 20

-genetic variation
-overproduction
-struggle for existence
-survival of the fittest
-advantageous characteristics passed on to offspring

Question 21

define natural selection

Answer 21

process where individuals with advantageous features are more likely to survive, reproduce, and pass their alleles to the next gen.

Question 22

stages for natural selection in cactus

Answer 22

-cactis with either long or short rooted alleles
-in wet season, more offspring produced than environment can support
-competition of water in dry season
-only long rooted survive because they can access deeper water. Short rooted die
-long rooted reproduce and pass their alleles, more long rooted alleles in population

Question 23

explain how population of antibiotic-resistant bacteria develop

Answer 23

-this is an example of natural selection
-some bacteria are mutated so there is variation
-normal bacteria die when exposed to antibiotics but mutated bacteria survive, reproduce and pass on their alleles .
-this happens over many gen. until antibiotic resistant bacteria are common in the population

Question 24

what is antibiotic bacteria have

Answer 24

resistantance, not immunity

Question 24

difference btw natural & artificial selection: agent of selection

Answer 24

-natural - nature
-artificial - man

Question 25

difference btw natural & artificial selection: species chance for survival

Answer 25

-natural - High: adapted to survive in environment
-artificial - Low: chosen to benefit man/ more likely inbred

Question 26

difference btw natural & artificial selection: speed of change

Answer 26

-natural - slower
-artificial - faster

Question 27

difference btw natural & artificial selection: examples

Answer 27

-natural - cactus root length, giraffe neck length
-artificial - dairy cows, domesticated dogs, modern corn

Question 28

how to measure effectiveness of antibiotic on bacteria

Answer 28

measure diameter of circle

Question 29

factors that cause mutation

Answer 29

-radiation causes
-chemical causes
-natural causes

Question 30

note: all genetic variation are mutations

Question 31

how are new alleles created

Answer 31

mutation which rarely happen

Question 32

how to find % change

Answer 32

diff/ org x 100%

Question 33

how does a flower develop bigger leaf size over time

Answer 33

-This is an example of natural selection
-There was a mutation which cause leaf sizes to increase
-plants with smaller leaf sizes could trap less sunlight and photosynthesize less than plants with bigger leaf sizes so they died and couldn’t pass their alleles
-Plants with larger leaf sizes survived and passed on their alleles.
-This happens over multiple gen. until big leaf sizes as common in the population

Question 34

2 useful characteristics of saddleback pigs from wild pigs

Answer 34

-no tusk
-larger animal