B7

Question 1

why is a rainforest a stable ecosystem

Answer 1

outputs or losses by system are balanced by the gains

materials cycle through closed loops so everything is recycle

eg water taken through roots and
used by trees but most lost through transpiration

water vapour lost from trees not rainforest by firing clouds and falls as rain which enters soil

Question 2

what is transpiration

Answer 2

evaporation of water from the leaves

Question 3

what are cloud forests

Answer 3

many tropical rainforests have low level cloud cover

Question 4

why do many plants reproduce

Answer 4

increase survival

Question 5

how do plants produce lots of offspring

Answer 5

each flower is a reproductive structure

where seeds are produced

flowers likely to produce lots of pollen

more pollen more likely to fertilise ovule and form seed

overproduction uses valuable energy but it’s not wasted

Question 6

what is pollen

Answer 6

plants make sex cells which need to get transferred to the formal part of the plant

Question 7

why is energy during overproduction not wasted

Answer 7

not wasted because materials are recycled into ecosystem

eaten or decomposed

Question 8

how is no ecosystem a perfect closed loop

Answer 8

but all water lost forms clouds

water that does fall may enter rivers and leave rainforest which enters other ecosystems

o2 and co2 gases may diffuse away in air

animals and plants migrate ecosystems which means material is lost

Question 9

how can a plant migrate

Answer 9

seeds in wind and animals (fur and poo)

Question 10

why is it an advantage for plants to distribute far

Answer 10

more likely to grow and survive and as it’s away from competing plants

Question 11

environmental problems from deforestation

Answer 11

soil erosion

global weather systems

Question 12

soil erosion

Answer 12

roots from trees and plants help bind soil together so it stays in one place

leaves help protect the soil from frequent rainfall

removing trees and plants means soil is easily washed away

Question 13

what can soil erosion cause

Answer 13

washed away soil can clog rivers which causes floods

Question 14

how does deforestation affect global weather

Answer 14

rainforests help to make clouds and rain

removal of trees has effects on the weather in the rest of the world

making it more unpredictable and extreme

eg
drought leads to crop failure and famine

Question 15

how do adaptations happen

Answer 15

reproduction over time

there is varied offspring with new or enhanced features which increase chance of survival

these survive and reproduce

Question 16

polar bear adaptations

Answer 16

long fur and layer of fat to trap air under skin for insulation to protect form cold

low surface area to volume ratio - less skin surface for their size and weight because they are rounded

white fur - camp

Question 17

what are behavioural adaptations

Answer 17

to prevent heat loss

features of behaviour that help organism to survive

hibernating

Question 18

hibernation

Answer 18

sleep through winter

don’t waste food and energy

fatten up through hot seasons then hibernate

Question 19

other ways animals prevent coldness

Answer 19

migration to warmer area

e.g birds

Question 20

the pompeii worm

Answer 20

lives in deep sea hydrothermal vents

has to withstand heat and pressure

covered by bacteria and lives inside papery tube for insulation

secretes mucus to feed bacteria

Question 21

animals living in heat

Answer 21

high SA: volume

thinner

little fur

preventing insulation

live in burrows and find shade

animals hunt in night

animals produce concentrators water

scales prevents water loss

long nostrils water vapour trapped in exhaled air and can be reabsorbed into body

Question 22

how does camel store water

Answer 22

stored fat in hump

breaks fat down for energy in respiration and by product is water and cow can drink this

Question 23

how does cacti prevent water loss

Answer 23

low SA by no leaves and can store water in fleshy stems

Question 24

how does transpiration happen

Answer 24

through tiny holes called stomata

Question 25

how do some fish live in freezing water

Answer 25

protein in blood that acts as an anti freeze

stops cells freezing making them damaged

Question 26

genetically modified tomatoes

Answer 26

has gene for the fish protein so it can grow in cold climates

Question 27

what are extremophiles

Answer 27

microorganisms living in extreme environments

adapted so enzymes work at extreme temps

Question 28

what do organisms compete for

Answer 28

things that are scarce

Question 29

what is a habitat

Answer 29

place where organism or population lives

can be home to different species that may depend on each other - interdependent

finely balanced

Question 30

what is a food web

Answer 30

when all animals and plants depend on eachother for energy in a habitat

Question 31

changes in habitat

Answer 31

rainfall or temp change

another animal entering - more competition

makes it harder to survive

Question 32

why do companies survey environmental impact

Answer 32

may disrupt habitats and food webs with buildings

have to minimise damage

Question 33

what is speciation

Answer 33

when two populations of species become so different they can produce fertile offspring

Question 34

how does speciation occur

Answer 34

if groups become isolated from eachother

Question 35

how does population barriers occur

Answer 35

through barriers which prevent the exchange of genes