4.2 Variation & modern examples of Evolution

Question 1

(variation) what is variation?

Answer 1

differences in characteristics within and between species

Question 2

(variation) what is interspecific variation?

Answer 2

variation or differences between different species

Question 3

(variation) what is intraspecific variation?

Answer 3

differences between different organisms of the same species

Question 4

(variation) give an example of interspecific variation:

Answer 4

rat has four legs and fur

snake has no legs and no fur

Question 5

(variation) give an example of intraspecific variation?

Answer 5

people differ in height, eye colour and build

Question 6

(variation) what are the two causes of variation?

Answer 6

environment

genes

Question 7

(variation) give examples of environmental factors that can cause variation:

Answer 7

climate
diet
accident
culture
lifestyle
diseases 
resources
predators
war

Question 8

(variation) how is the flower colour of hydrangeas affected by the environment?

Answer 8

soil acidity
acid - blue flowers
alkaline - pink flowers

Question 9

(variation) scars are an example of variation caused by what?

Answer 9

the environment

occur due to accident or disease

Question 10

(variation) environment - a plant in the sun is more likely to do what?

Answer 10

grow than one in the shade

Question 11

(variation) genetic variation can be due to what 5 factors?

Answer 11

alleles
mutation
meiosis
sexual reproduction
chance

Question 12

(variation) genes have different alleles, which produce what?

Answer 12

differences in characteristics e.g. there are 3 alleles for blood group depending on combination 1 of 4 groups can be produced

Question 13

(variation) what are mutations?

Answer 13

changes in the DNA sequence which can affect the proteins coded for affecting characteristics

Question 14

(variation) when can a mutation be passed onto the offspring and inherited?

Answer 14

if it occurs in the gametes

Question 15

(variation) how can variation occur in meiosis?

Answer 15

independent assortment of homologous chromosomes

crossing over

Question 16

(variation) in sexual reproduction offspring inherits what, resulting in what?

Answer 16

genes from both parents

results in differences between parents and offspring

Question 17

(variation) how does chance result in genetic variation?

Answer 17

it is chance as to which gametes combine resulting I genetic variation between siblings

Question 18

(variation) how can height be determined by a combination of genetic and environmental factors?

Answer 18

you may inherit genes to grow tall

but if you’re malnourished you may not grow to this height

Question 19

(variation) how can skin colour be determined by a combination of genetic and environmental factors?

Answer 19

determined by genes in how much melanin your skin contains

skin darkens due to sunlight exposure

Question 20

(variation) what is continuous variation?

Answer 20

variation can take any value within a range - contained by multiple genes e.g. height

Question 21

(variation) what is discontinuous variation?

Answer 21

variation within specific categories - caused by a single gene e.g. blood group

Question 22

(modern examples) methicillin resistant staphylococcus aureus has developed what?

Answer 22

resistance to many antibiotics

Question 23

(modern examples) as bacteria reproduce rapidly what occurs quickly?

Answer 23

evolution

Question 24

(modern examples) bacteria’s DNA can be altered and in some instances leads to resistance to what?

Answer 24

methicillin

Question 25

(modern examples) these bacteria can survive and reproduce passing on what?

Answer 25

the resistance allele

Question 26

(modern examples) pre industrial revolution most peppered moths were what colour?

Answer 26

pale - camouflaged by tree bark

dark moths usually eaten

Question 27

(modern examples) during the industrial revolution what happened to the bark and then the peppered moths?

Answer 27

bark darker

darker moths camouflaged so less likely to be eaten so their population size rapidly increased

Question 28

(modern examples) now pollution levels have decreased and more trees are light coloured what is happening to the frequency of the pale allele?

Answer 28

increasing

Question 29

(modern examples) what are sheep blowflies?

Answer 29

lay their eggs around faecal matter around a sheep they hatch and cause sores

Question 30

(modern examples) in 1950s what was used to kill the blowflies and what did the blowflies develop after six years?

Answer 30

pesticide - diazinon

blowflies developed a high level of resistance

Question 31

(modern examples) what was not found in blowflies 70 years old?

Answer 31

this resistance

Question 32

(modern examples) there is a new strain of flavobacterium living in waste water from where?

Answer 32

factories producing nylon 6

Question 33

(modern examples) the strain of flavobacterium has evolved to do what?

Answer 33

digest nylon

Question 34

(modern examples) what was the flavobacterium mutation due to?

Answer 34

gene duplication frame shift mutation

Question 35

(modern examples) how is the mutation in the flavobacterium beneficial?

Answer 35

humans can use it to clear factory waste

bacteria provided with a new source of nutrients