evolution and variation (ch12)

Question 1

what does the theory of evolution state

Answer 1

that all species evolved from simple life forms that developed 3 billion years ago

Question 2

what was lamarcks theory

Answer 2

inheritance (genetically passing on) of acquired characteristics and characteristics that arent used eventually disappear

Question 3

why is lamarcks theory false

Answer 3

implies that all organisms gradually become more complex and simple organisms disappear

Question 4

what is darwins theory

Answer 4

genetic variation -> too many organisms need to compete for food and water -> natural selection (those who are best adapted survive)-> animals best adapted for environment have the most competitive environments -> more likely to survive and pass on allele

Question 5

what is mutation

Answer 5

a change in genetic material

Question 6

what is natural selection

Answer 6

process by which evolution takes place and only those who are most fitted to the environment survive (peppered moth example)

Question 7

what is variation

Answer 7

any difference between individuals in a species

Question 8

how do you answer a 6 mark natural selection question

Answer 8

1)start with mutation
2) competitive advantage (state what it is and how it helps them)
3)more likely to survive and reproduce to pass on allele
4)specify answer to example

Question 9

define species

Answer 9

a group of organisms with similar characteristics and interbreed to produce fertile offspring (donkey+horse are infertile since theyre seperate species)

Question 10

how do species change

Answer 10

-when small populations become isolated to a different environment by:
1) geographical isolation (ex: island formation or mountain ranges)
2)deforestation
3) construction of new roads

Question 11

how does speciation occur

Answer 11

1) small population becomes geographically isolated
2) different environmental conditions they must adapt to
3) mutation -> variation in new population
4)new population can no longer interbreed with the old one and produce a fertile offspring

Question 12

how do animals adapt in cold climates

Answer 12

larger than usual to have a small SA:V and reduce energy transfer
very insulated blubber from the inside and thick fur coat on the outside
huddle to reduce exposed surface area

Question 13

how do animals benifit from camouflage

Answer 13

-predators avoid being seen by prey and prey hide from predators

Question 14

how do animals adapt in hot and dry climates

Answer 14

-large SA:V to transfer as much energy to environment as possible
-dont sweat often to reduce water loss
-thin fur and little body fat to make it easier to transfer energy and cool down

Question 15

what happens if plants are in hot and dry conditions

Answer 15

photosynthesis and respiration take place too rapidly and the plant looses water

Question 16

how do plants change their surface area to adapt to environments

Answer 16

-broad leaves with large surface area collect dew
- most animals in dry areas have a small sa:v ratio and curled leaves to cut down on water loss

Question 17

how do cuticles help plants adapt to their environment

Answer 17

they have a waxy layer coating the leaf that stops water from evaporating

Question 18

how are cacti adapted to suit their environment

Answer 18

leaves are reduced to spikes that discourage animals from eating them and they have a large spine full of water storage tissue

Question 19

how do plants collect water

Answer 19

they often have a large root sytem to absorb as much water as possible from the soil

Question 20

what happens if organisms loose to their competitors

Answer 20

they either die , migrate or find a new stratigy

Question 21

what are the 4 main things animals compete for

Answer 21

water
food (prey compete not to be eaten and predators compete for prey)

Question 22

why is it a problem when animals only have 1 food source

Answer 22

all animals in the same species need to compete for it (intraspecific)

Question 23

why do animals need their own territory

Answer 23

so they can have more space to breed and increase their species

Question 24

what is meant by intraspecific

Answer 24

when animals from the same species compete for resources

Question 25

what is meant by interspecific

Answer 25

when different species need to compete for territory

Question 26

what do plants need to compete for

Answer 26

-water to keep tissue supported and rigid
-light for photosynthesis
-space to grow
-nutrients for chemicals needed to support cells

Question 27

what do parasites feed on

Answer 27

hosts. parasite is benifited while host is harmed

Question 28

what is the parasite that causes malaria

Answer 28

plasmodium

Question 29

what types of parasites live inside hosts and what parasites live outside

Answer 29

inside; tapeworms
outside; hair lice

Question 30

how are fleas adapted against hosts

Answer 30

they release a chemical that stops blood clotting so they can get constant blood flow
sharp teeth to pierce skin and not fall off easily when scratched
long legs to jump quickly from host to host

Question 31

what do tapeworms do

Answer 31

attach themselves to the hosts small intestine and absorb nutrients which causes vomiting and weightloss

Question 32

how are tapeworms adapted to feed on hosts

Answer 32

-multiply asexually very quick
hooks to hold onto small intestine
very long to increase surface area so more efficient absorption of nutrients
thick cuticle acts as protection from digestive enzymes

Question 33

how is malaria transmitted

Answer 33

by mosquitos

Question 34

explain the plasmodium life cycle

Answer 34

1) mosquito bites malaria-infected host
2) An infected mosquito bites another human and injects infected blood into them
3)plasmodium infects liver cells and then multiplies
4) infection reaches red blood cells till they burst

Question 35

what happens if you have a hetrozygous sickle cell anemia gene (carrier)

Answer 35

-competitive advantage since youre immune1 to malaria
-survive and reproduce
-then pass on sickle cell anemia gene to offspring

Question 36

why were moths being marked under their wings instead of above

Answer 36

so their camouflage isnt changed

Question 37

why did rails disappear from their previous inhabited islands

Answer 37

• too many competitors
  -new diseases
  -new preditors

Question 38

describe 3 ways fossils can be made

Answer 38

-bones are preserved
-lack of oxygen causes decay
-organism is replaced with debris as they decay

Question 39

suggest a reason why sheep decreased in size over 25 years

Answer 39

• mutataion or variation in gene
  -warmer and dryer now
  -smaller lambs survive
  -smaller sheeps breed and pass on the allele to offspring