B7 Flashcards
why is a rainforest a stable ecosystem
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
what is transpiration
evaporation of water from the leaves
what are cloud forests
many tropical rainforests have low level cloud cover
why do many plants reproduce
increase survival
how do plants produce lots of offspring
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
what is pollen
plants make sex cells which need to get transferred to the formal part of the plant
why is energy during overproduction not wasted
not wasted because materials are recycled into ecosystem
eaten or decomposed
how is no ecosystem a perfect closed loop
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
how can a plant migrate
seeds in wind and animals (fur and poo)
why is it an advantage for plants to distribute far
more likely to grow and survive and as it’s away from competing plants
environmental problems from deforestation
soil erosion
global weather systems
soil erosion
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
what can soil erosion cause
washed away soil can clog rivers which causes floods
how does deforestation affect global weather
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
how do adaptations happen
reproduction over time
there is varied offspring with new or enhanced features which increase chance of survival
these survive and reproduce
polar bear adaptations
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
what are behavioural adaptations
to prevent heat loss
features of behaviour that help organism to survive
hibernating
hibernation
sleep through winter
don’t waste food and energy
fatten up through hot seasons then hibernate
other ways animals prevent coldness
migration to warmer area
e.g birds
the pompeii worm
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
animals living in heat
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
how does camel store water
stored fat in hump
breaks fat down for energy in respiration and by product is water and cow can drink this
how does cacti prevent water loss
low SA by no leaves and can store water in fleshy stems
how does transpiration happen
through tiny holes called stomata
how do some fish live in freezing water
protein in blood that acts as an anti freeze
stops cells freezing making them damaged
genetically modified tomatoes
has gene for the fish protein so it can grow in cold climates
what are extremophiles
microorganisms living in extreme environments
adapted so enzymes work at extreme temps
what do organisms compete for
things that are scarce
what is a habitat
place where organism or population lives
can be home to different species that may depend on each other - interdependent
finely balanced
what is a food web
when all animals and plants depend on eachother for energy in a habitat
changes in habitat
rainfall or temp change
another animal entering - more competition
makes it harder to survive
why do companies survey environmental impact
may disrupt habitats and food webs with buildings
have to minimise damage
what is speciation
when two populations of species become so different they can produce fertile offspring
how does speciation occur
if groups become isolated from eachother
how does population barriers occur
through barriers which prevent the exchange of genes
