2a

Question 1

how have desert animals adapted to save water and keep cool and survive

Answer 1

they have a large surface area compared to volume, they urinate less, sweat less and well camouflaged

Question 2

how have artic animals adapted to reduce heat loss and survive

Answer 2

they have a small surface area compared to volume, they are well insulated, thick layer of blubber, store energy, thick hairy coats and greasy hair whilst also being camouflaged.

Question 3

how have desert plants adapted to having little water

Answer 3

they have a small surface areas compare to volume, plants like cacti have spikes instead of leaves to reduce water loss through water vapour, they have water storage tissues e.g. cacti store water I their thick stems, they also maximise water absorption by having shallow but expensive roots and others have deep roots.

Question 4

name 3 ways plants and animals use their special features to help protect them from being eaten

Answer 4

some plants have amour thorns or even spikes, others produce poisons, others have warning colours to scare off predators

Question 5

what resources do plants compete for

Answer 5

light, space, water and minerals

Question 6

what resources do animals compete for

Answer 6

space (territory), food, water and mates

Question 7

list the 4 living factors that change all the time in an environment

Answer 7

1. a change in the occurrence of infectious diseases
2. a change in the number of predators
3. a change in the number of prey or availability of food sources
4. a change in the number of types of competitors

Question 8

list the 3 non living factors that change all the time in an environment

Answer 8

1. change in the average temp
2. a change in the average rainfall
3. a change in the level of air or water pollution

Question 9

name 3 environmental changes affecting populations

Answer 9

population size increase, population size decrease, population distribution changes

Question 10

what living indicator suggests a high amount of sulphur dioxide in a certain are

Answer 10

if they is a low level of sulphur dioxide there will be lots of lichen in a nearby river but can also work vice versa

Question 11

if you find mayfly larvae in a river, what does it suggest

Answer 11

it indicates that the water is clean

Question 12

if you see rat tailed maggots and sludge worms in and around a river what could this indicate

Answer 12

it could indicate a high level of water pollution

Question 13

what is a tropic level

Answer 13

a feeding level

Question 14

what does each stage of the pyramid of biomass represent

Answer 14

the big bar along the bottom of the pyramid always represents the producer, the next bar will be the primary consumer, then the secondary consumer and so on up the food chain

Question 15

how is most of the biomass lost as it progresses through the food chain

Answer 15

it is lost as heat

Question 16

what conditions do microorganisms work best in

Answer 16

warm and moist conditions

Question 17

plants take elements like carbon, oxygen, hydrogen and nitrogen and turn them into…

Answer 17

complex compounds like carbs, proteins and fats

Question 18

how do elements like carbon, oxygen, hydrogen and nitrogen get returned back to the environment a put back in the soil

Answer 18

these elements are returned to the environment in waste products produced by the microorganisms or when the organisms die. These materials decay because they are broken down (digested) by microorganisms, that’s how the elements get put back into the soil

Question 19

explain the carbon cycle

Answer 19

the whole thing is powered by photosynthesis. CO2 is removed from the atmosphere by plants and algae, and the carbon is used to make carbohydrates, fats and proteins in the plants and the algae. Some of the carbon is returned to the atmosphere when they respire, some of the algae becomes p[art of the carbs, protein etc. The carbon then moves through the food chain. Some of the carbon is returned to the atmosphere as CO2 when animals respire. When plants and algae die detritus feeders and microorganisms feed on their remains and when they respire CO2 is returned to the atmosphere. Detritus feeders and microorganisms also break down animal waste, compounds in the waste are taken up from the soil by plants as nutrients, they are put back in the food chain. Some useful plant and animal products like wood and fossil fuels are burnt through combustion releasing CO2 back into the air, then the process starts again

Question 20

what are the two types of variation

Answer 20

genetic variation and environmental variation

Question 21

what are genes

Answer 21

genes are the codes inside your cells that control how you’re made

Question 22

what causes genetic variation

Answer 22

most animals (and quite a lot of plants) get some genes from the mother and some from the father, this combining of genes from 2 parents causes genetic variation because no two species are identical (except identical twins)

Question 23

what causes environmental variation

Answer 23

any difference that has been caused by the conditions something lives in is an environmental variation.

Question 24

what does the nucleus contain

Answer 24

genetic material in the form of chromosomes

Question 25

how many pairs of chromosomes does a human cell contain

Answer 25

23 pairs (they are always I pairs, one from each parent

Question 26

what do chromosomes carry

Answer 26

chromosomes carry genes, different genes control the development of different characteristics

Question 27

what length is a gene compared to a chromosome

Answer 27

a gene is a short length of the chromosome

Question 28

what length is a gene compared to DNA

Answer 28

a gen is quite a long length of DNA

Question 29

what is an allele

Answer 29

different versions of the same gene are called alleles

Question 30

what is sexual reproduction

Answer 30

sexual reproduction is where genetic information from 2 organisms (mother and father) is combined to produce offspring which are genetically different to either parent

Question 31

in humans how many chromosomes does each gamete contain

Answer 31

23 each

Question 32

what does sexual reproduction involve

Answer 32

sexual reproduction involves the fusion of male and female gametes

Question 33

what is asexual reproduction

Answer 33

it is where an ordinary cell can make a new cell by dividing in two

Question 34

explain the process of asexual reproduction

Answer 34

in asexual reproduction there is only one parent, there’s no fusion of gametes, no mixing of chromosomes and no genetic variation between parent and offspring, they are clones. X shaped chromosomes have 2 identical halves so each chromosomes splits down the middle to form 2 identical half chromosomes whilst a membrane forms around both. Also the DNA replicates itself to form 2 identical cells with complete sets of X shaped chromosomes

Question 35

what 2 ways can plants be cloned by using asexual reproduction

Answer 35

from cuttings and by tissue culture

Question 36

how an plants be cloned from cuttings

Answer 36

gardeners can take cutting from good parent plants and then plant them to produce genetically identical copies (clones) of the parent plant, this is quick and cheap

Question 37

how an plants be cloned by tissue culture

Answer 37

a few plant cells are put in a medium with hormones and they grow into new plants,clones of their parents. This can be quick, made in a very small space and grown all year round.

Question 38

how does an embryo transplant work with prize cows and bulls

Answer 38

sperm cells are taken from a prize bull and egg cells from a prize cow. The sperm are then used to artificially fertilise an egg cell. The embryo that develops is then split many times to form clones before any cells become fertilised. These cloned embryos can then be implanted into lots of other cows where they grow into baby calve which will be genetically identical to the best cow and bull a farmer has.

Question 39

explain the process of adult cloning

Answer 39

adult cell cloning involves taking an unfertilised egg cell and removing its nucleus then a complete set of chromosomes from an adult body cell is inserted into the empty egg cell. The egg cell is then stimulated with an electric shock which makes the embryo divide like normal. The embryo is then implanted into an adult female to grow into a clone of the original adult body cell. This was first used on the famous clone sheep dolly.

Question 40

pros and cons of cloning

Answer 40

cons
reduced gene pool, leads to age related disorders, not as healthy as the original, could lead to clone children with disabilities
pros
reduces endangered species, leads to greater understanding of the development of the embryo,

Question 41

explain the method used in genetic engineering (cut and paste)

Answer 41

a useful gene is cut from one organism’s chromosome using enzymes, enzymes are then used to cut another organism’s chromosome and then to insert the useful gene. Scientists can use this method to do all sorts of things, e.g. the human insulin gene can be inserted into bacteria to produce human insulin.

Question 42

pros of genetically modified crops

Answer 42

GM crops can increase the yield of a crop, making more food.
people living in developing nations often lack nutrients in their diets, GM crops could be engineered to produce the nutrients that are missing
GM crops are already being grown elsewhere in the world without any problems

Question 43

cons of genetically modified crops

Answer 43

some say that it affects weds and flowers in surrounding area and s reduces farmland biodiversity
some people say it not safe, and are worried about developing allergies towards it
transplanted genes may get out into the natural environment e.g. the herbicide resistant gene may be picked up by weeds creating a new ‘super weed’ variety

Question 44

what is a mutation

Answer 44

it is a change in an organisms DNA

Question 45

what wasdarwins theory of natural selection

Answer 45

individuals within as species show variation because of the differences in their gens e.g. some rabbits have big ears others have small ones. Individuals which have characteristics that make them better adapted to their environment have a better chance of survival and are more likely to breed successfully (rabbits with bigger ears can hear foxes coming and so are less likely to be eaten). The genes that provide useful characteristics are more likely to be passed onto the next generation

Question 46

why was there controversy over darwins theory

Answer 46

it went agaist common beliefs, not enough evidence

Question 47

what was Lamarck’s theory on evolution

Answer 47

Lamarck argued that if a characteristic was used a lot by an organism then it would become more developed during its lifetime e.g. if a rabbit used its legs to run a lot then its legs would get longer and these characteristics would be passed onto the next generation (of course this is not the case)