B4 Flashcards
what are the benefits of transpiration?
there is constant water to help keep plant cool, for photosynthesis.
water creates turgor pressure which helps support the plant and stops it wilting
minerals needed by plant can be brought in form the soil along with water
what four things affect transpiration rates?
light intensity
temperature
air movements
air humidity
what needs to be done to increase transpiration?
increase in light intensity, temp and air movements
decrease in humidity
how does light affect transpiration
brights means more as during the dark stomata close. photosynthesis cant happen in the dark so they close. when stomata are closed water canot escape
how does temp affect transpiration?
when warm particles have more energy to evaporate and diffuse out of the stomata
ho does air movement affect transpiration?
air movements helps it become faster as if there isnt any then the water just surrounds the leafs and wont move away. high concentration inside and outside so no movement. wind helps move water vapor to allow transpiration
how does air humidity affect transpiration?
if the air is humid there is lots of water already in it so there is no difference between leaf and air. diffusion happens fastest when there is a big differnece i concentration
how have plants adapted to not lose water?
waxy cuticle covering upper epidermis to make it waterproof
stomata on underside to slow diffusion in the cold and dark
bigger and larger the number of stomate means more water is lost. plants in hot climates have few small ones on the underside of leaf.
what caused stomata to close and open?
guard cells have a special kidney shape that opens and closes he stomata as the guard cells go turgid or flaccid.
what do stomata do?
allow gasses in and out for photosynthesis
when are stomata usualy open and closed?
open during day as they are sensitive to light. closed at night when its dark
what are the three minerals needed for plant growth?
nitrates, phosphates, potassium
what are nitrates needed for in plants?
for making amino acids and proteins, for cell growth.
if a pant does not have enough nitrates what happens
growth will be poor and will have yellow older leaves
what are phosphates needed for?
respirations and growth. dna and cell membrane productions
if a plant doesn’t have enough phosphates what happens?
poor root growth and discolored leaves
what is potassium needed for ?
to help enzymes needed for photosynthesis and respirations.
if a plant doesnt have enough potassium what happens?
poor flower and fruit growth. discolored leaves too
why is magnesium used and why in small amounts?
for making chlorophyll needed for photosynthesis. without it leaves turn yellow
how are minerals taken in?
by the roots using active transport
why doesnt diffusion of minerals work in roots?
because there is a small concentration of minerals in the soul and its higher in the roots hairs so it wont go in.
what is active transport?
uses energy from respiration to help pull minerals into the roots against the concentration gradient
what causes decay?
microorganisms like soil bacteria nd fungi known as decomposers
what does the rate of decay depend on
temperatures (needs to be warm) water amount (needs to be moist for fast decay) oxygen amount (decay is faster when there is more oxygen available)
what are the optimum conditions for decay?
warm, moist, plenty of oxygen.
this causes microorganisms to reproduce nd grow more quickly and can then decay other living things better.
what is a detritivore?
feed on dead and decaying matter. they break it up into smaller bits, this produces a bigger surface area for smaller decomposers to decay it
what is a saprophyte?
they also feed on decaying matter but they do so with extracellular digestion/ they feed by secreting digestive enzymes onto the material outside their cells. the enzyme breaks down the material in to smaller bits which can then be absorbed by the saprophytes. usually fungi
what are the methods of food preservation?
canning cooling freezing drying adding slat or sugar adding vinegar
how do these methods of food preservation work?
keeps decomposers out, slows down their reproduction rate, stops them reproducing at low temps, takes away water which they need to decompose, damage the cells, kill them with acid
what is intensive farming?
trying to produce as much food as possible form your land,animals or plants
what are the most popular methods of intensive farming?
reducing energy lost at each stage in a food chain to make it more efficient
how is intensive farming, reducing of energy lost achieved?
herbicides kill weeds. this allows more energy form sum to fall on crops not weeds
pesticides kill animals that eat crops. no energy is transfered to to other food chains
battery farming animals. kept close together to stop wasted energy as they move
what does intensive farming allow us to do?
produce lots of food form less land witch means a hugh variety of top quality food all year round at cheap prices
what is it called when plants are gown without soil?
hydroponics, its another form of intensive farming where the plants are grown nutrient solutions instead of soil.
what are the advantages of hydroponics?
mineral levels can be controlled more accurately. disease can also be controlled
what are the disadvantages of hydroponics?
lots of fertilizers are used. there is also no soil to anchor the roots and support the plants
what are the environmental issues with hydroponics?
removal of hedges to make fields destroys habitats and leads to soil erosion
careless use of fertilizers can lead to eutrophication
farming of animals intensively is harmful and cruel (battery chickens)
wht is the issue with pesticides?
they can also kill animals that are not pests which can lead to shortage of food for animal higher up food chain
what is the problem of pesticides being passed up food chains?
they can stick in ecosystems and be passed along chains. it accumulates along the chain and gets more toxic towards the top where levels are highest
what was the case of DDT and otters?
a pesticide called DDT was used and it accumulated along food chains and the otter ended up getting toxic levels of it and almost wiping them out
what is biological control?
using living things instead of chemicals to control a pest.
examples of biological control?
aphids eat roses and vegetables. pest. ladybirds are predators of aphids so they can keep numbers down
what are the advantages of biological control
no chemicals means less pollution and disruption of food chains. less risk to people e eating foods
you dont have to keep repeating treatments like chemicals
what are he disadvantages of biological control?
a predator introduced might be useless and not eat pest
predator could eat useful species
predators species might increase and get out of control
predator might not stay in area where its needed
what are orgainc fertilisers?
animal manure/compost
recycles nutrients left in plant and animal waste. it is not as good as fertilizers but its bette for environment
what is crop rotation?
growing a cycle of different crops on a field each ear. it stops pests and diseases of one crops building up and stops nutrients running out. most crop rotations include nitrogen fixing bacteria crops such as legumes that put nitrates back into the soil
how is varying seed planting times used in faring?
it avoids major pests for that crop and eliminates the use of pesticides
what methods are used in organic farming/?
organic fertilizers crop rotation weeding varying seed planing times biological control
orgainicwhat are the advantages of organic farming?
fewer chemicals. less rick of toxic chemicals in food better for the environment. less river pollution. it doesn't disrupt food chains ethical to animals
what are the disadvantages of organic farming?
takes more space than intensive
labour intensive, more jobs, more expensive
cant grow as much food
