Energy flow in ecosystems Flashcards
ecology
the study of living things and their interactions with each other and their environment
ecosystem
a self-supporting sysetm of organisms interacting with each other and their environment
habitat
a place within an ecosystem where specific organisms live, e.g. pond or woodland
population
all of the organisms of a particular species found in an ecosystem
community
all the different species living in an ecosystem
competeition
the struggle for resources
biotic factor
all biological (living) components of the ecosystem (predation, food, competition, decomposition)
abiotic factor
(all the non-biological components of the ecosystem (including water, air, temperature, sunlight, etc…)
producer
organism that can make its own food (= autotroph)
primary consumer
organism that obtains energy by feeding on producers (=heterotroph)
secondary consumer
organism that obtains energy by feeding on primary consumer (= heterotroph)
herbivore
animal that feeds on plants only
carnivore
animal that feeds on other animals only
tertiary consumer
animal that has no natural predators
prey
animal hunted and killed by another animal for food
predator
animal that preys on other animals
detritivore
organism that feeds on dead/ decaying organic material (e.g. worm vulture) (=saprotroph)
decomposers
organism that decompose (break down) organic material (e.g. bacteria + fungi)
heterotroph
organism that feeds on other organisms (= consumer)
autotroph
organism that can make its own food (= producer)
saprotroph
organism that feeds on decaying organic material (= detritivore)
food chain
shows simple feeding relationships within an ecosystem
food web
shows complex feeding relationships within an ecosystem
trophic level
stage in a food chain (= feeding level)
pyramids of number
represents the number of organisms in each trophic level in a food chain (irrespective of their mass)
pyramids of biomass
represents the total mass of all the organisms in each trophic level (irrespective of their number)
pyramid of energy
shows the energy transferred through each trophic level in a food chain
quadrat
a square frame (sometimes gridded) for sampling organisms
The organisms: leaf, worm, mouse, owl
Label their trophic levels
Whether their are a producer or consumer and which consumer they are (primary, secondary…)
Whether they are prey or a predator
Whether they are a herbivore or carnivore
leaf → worm → mouse →owl
trophic level 1 → trophic level 2 → trophic level 3 → trophic level 4
prodcuer → primary consumer → secondary consumer → tertiary consumer
(N/A) → herbivore → carnivore → top carnivore
(N/A) → prey → prey, predator → predator
What would happen if the fox population decreased? (two outcomes)
squirrel population increases
woodmouse population increases
What would happen if the caterpillar population decreased? (two outcomes)
shrew population decreases
earthworm population decreases
Food chains show the direction of … transferred between the trophic levels
Energy is transferred as … (in food molecules)
Chemical energy is stored as new … (mass of an organism)
Food chains show the direction of energy transferred between the trophic levels
Energy is transferred as chemical energy (in food molecules)
Chemical energy is stored as new biomass (mass of an organism)
The population of each organism in a food chain can be shown in a pyramid of …
The … of each box is determined by the number of organisms at each trophic level
The population of each organism in a food chain can be shown in a pyramid of numbers
The width of each box is determined by the number of organisms at each trophic level
Sketch a pyramid of numbers for this food chain:
50 clovers → 20 snails → 5 thrush → one sparrowhawk
The … of each trophic level in a food chain is shown in a pyramid of biomass
The biomass of each trophic level in a food chain is shown in a pyramid of biomass
Sketch a pyramid of biomass for this food chain:
oak tree → caterpillar → mouse → owl
(1 x 50kg) → (50 x 0.2kg) → (5 x 0.5kg) → (1 x 1kg)
oak tree → caterpillar → mouse → owl
(50kg) → (10kg) → (2.5kg) → (1kg)
Between each trophic in a food chain, not all energy is converted into new … in growth
Some … is …
Up to …% of energy can be lost in trophic levels
Between each trophic in a food chain, not all energy is converted into new biomass in growth
Some energy is lost
Up to 90% of energy can be lost in trophic levels
How is energy lost between each trophic level?
some energy is released in respiration (e.g. for movement or body heat)
not all energy is digested, some is excreted
some is converted into new biomass
not all of the organism is eaten
How can food production be made more efficient?
by decreasing the number of trophic levels in food chains
by limiting the movement of animals, so that less energy is lost
by increasing the temperature, so that less energy is lost through body heat - this is done by keeping the animals close together in a confined space
How are organisms in an ecostsytem continually interacting with each other?
e.g. through deeding or competition
How much energy eaten in food is used to build new biomass (new cells)?
a very small fraction - often less that 10%
Is it more efficient to eat plants or eat animals? Why?
it is more efficient to eat plants
you have decreased the number of trophic levels in the food chain
Why is it difficult to determine the number of organisms in a habitat?
plants could be spread out unevenly
some organisms can move (e.g. animals)
it wouldtake an incredibly long time - time constraints
What is an ideal sample size of an area?
10% of the area
What is a quadrat?
a square frame used for sampling
How do you use a quadrat?
layo ut a tape measure to mark out a sampling field
use a random number generator to get some coordinates (e.g. 4, 2)
count the number of organisms present in the quadrat
count the number of organisms found at the other coordinates (i.e. do repeats)
calculate the mean and use it to estimate the entire population size
In an experiment to investigate the population size of flowering plants, what type of variable is:
the habitat
the number of flowering plants
the habitat = independent, categorical
the number of flowering plants = dependent, discrete
For much of the year at ground level in Birnham Wood it is very dark during the day. However, some small plants do grow there. One of them is the Bird’s-Nest Orchid, which has pale brown leaves.
Suggest why it is dark at ground level in Birnham WOod for much of the year
the light is blocked by trees
For much of the year at ground level in Birnham Wood it is very dark during the day. However, some small plants do grow there. One of them is the Bird’s-Nest Orchid, which has pale brown leaves.
The Bird’s-Nest Orchid is not green like most other plants. Explain why the green colour is important to most plants
The green pigment in most plants is chlorophyll which is used in photosynthesis for plants to make their own food
For much of the year at ground level in Birnham Wood it is very dark during the day. However, some small plants do grow there. One of them is the Bird’s-Nest Orchid, which has pale brown leaves.
Suggest how the Bird’s-Nest Orchid is able to survive even though it is not green
it feeds on dead material/carnivorous
This is a food chain from a pond:
microscopic plants → microscopic animals → insects → fish
What is the term used to describe the fish?
top carnivore
Why is it an advantage for an animal at the top of a food web to feed on more than one type of organism?
it is easier to find prey / less competition
they can survive if one organism dies out
can feed in different seasons
better chance of a balanced diet
Why is it unusual to find food chains with more than five trophic levels?
most energy would be lost through, for example, respiration and excretion
energy decreases as the trophic level increases
What is decomposition and what does this process release?
decomposition is the breakdown of dead organisms, or other material, such as bread
this process releases inorganic minerals, such as nitrate or phosphate, and carbon dioxide into the air in respiration
Name two groups of organisms that can act as decomposers in food chains
bacteria
fungi
Describe the role of decomposers in the carbon cycle
they breakdown the remains of dead plants and animals and, in doing so, release carbon dioxide through respiration
Describe an investigation you could carry out in the laboratory to find theeffect of light intensity on the growth of plants. You should include ful experimental details in your account
Light intenisty is the independent variable of this experiment so I will choose three different light intensities to test on the plant; no light, dim light and harsh light
To make it a fair test, I will use the same species of plant and give the plant the same volume of water and keep them at room temperature - these are my control variables
For each of the light intensities I will measure plant growth over one week by measuring the height of the plant using a rule - this is my dependent variable
I will repeat my experiment three times to increase the reliability of my results
Describe how you could compare the population size of a plant growing in two different places. One place is on the side of the hill and the other place is on a piece of flat ground
I would plant the same specied of plant in a 0.5m2 quadrat
One quadrat would be on the side of the hill and the other on a piece of flat ground
After a week, i would count how many plants had grown in each quadrat
I would repeat the experiment three times
What seven ways can you improve crop yield?
soil minerals
soil structure
soil pH
water
carbon dioxde
heat
light
How do you control soil minerals? What is the reason for controlling this?
how: adding inorganic fertiliser or manure to soil
reason: extra minerals increase plant rate
How do you control soil structure? What is the reason for controlling this?
how: ploughing fields to break up contact soil
reason: allows better uptake of minerals and water because it’s easier for roots to grow in soil
How do you control soil pH? What is the reason for controlling this?
how: adding lime to acidic soil
reason: low pH can reduce uptake of minerals
How do you control water? What is the reason for controlling this?
how: watering
reason: required for photosynthesis
How do you control carbon dioxide? What is the reason for controlling this?
how: greenhouse (e.g. burning fossil fuels)
reason: required for photosynthesis
How do you control heat? What is the reason for controlling this?
how: greenhouse (e.g. burning fossil fuels)
reason: required for photosynthesis
How do you control light? What is the reason for controlling this?
how: greenhouse (e.g. artificial light)
reason: required for photosynthesis
What are pests?
organisms that reduce the yield of crop plants or farm animals (can be plants, animals, fungi, bacteria or viruses)
What do these kill:
herbicides
insecticides
fungicides
molluscides
herbicides kill plant petss
insecticides kill insects
fungicides kill fungi
molluscides kill molluscs
What are the advantages of pest control?
higher crop yield
What are the disadvanatges of pest control?
expensive
pest reistance
environmental damage
bioaccumulation
What is bioaccumulation?
pesticides stored in fatty tissue
What is biomagnification
pesticide concentration increases in higher levels of food chain
How does biological pest control work?
natural predators of pests
parasites of pests
pathogenic microorganisms (to cause disease of pest)
introduction of sterile males of pest (to prevent reproduction)
use of pheromones (to attract and trap pests)
herbivores (to reduce weeds)
How does crop rotation work?
used instead of monocultures
pests die out as they can’t live with the new crops
pests live in a particular area, feeding on that crop - if you change the crop, the pests die out as they can’t feed anymore
A farmer releases ladybird onto his tomato plants to reduce the number of aphids (ladybirds eat aphids that feed on tomatoes). What is the name given to this meyhod of reducig the number of insect pest?
biological control
Describe the disadvantages of using pesticides
bioaccumulation
affects other species
poisonous to humans
food chain disruption
pollution
needs reapplication
How do insect pests would affect crop yield?
crop yield would decrease
insect pests consme crops so there is less surface area so less photosynthesis
Explain why farmers often spray pesticide onto their crops
pesticides kill the organisms (pests) that reduces the yield of their crops
this protects their crops and allows for higher crop yield
Explain how fertilisers increase the yield of crops
fertilisers contain minerals, e.g. nitrate for amino acids, proten for chlorophyll
this increases the plant rate
Explain why increasing the temperature in a glashouse would affect the yield of crops
temperature is required for photosynthesis
the higher the temperature, the higher the rate of photosynthesis
this increases yield as plants grow more and grow faster
What is fish farming?
the raising of fish commercially in tanks or encolsures, usually for food
What are the advantages of fish farming?
meets quality of fish
water quality can be carefully monitored inclusing oxygenation and temperature (fish are kept in large seawater tanks)
shortfall of fish can be carefully monitored including diet and frequency of feeding
fish are protected against predators (not present in tanks) and parasites (by using pesticides)
selective breeding programmes can be used to improve the quality of fish (e.g. faster growth)
What are the disadvantages of fish farming?
potential for spreading of disease is larger (fish closer together)
overuse of antibiotics to treat disease
pollution of water with fish faeces and food pellets (can lead to eutrophication)
pesticides used to kill parasites can be toxic
food pellets derived from wild fish - leads to a further reduction in wild fish stock
What is eutrophication?
an increase of nutirents in water lead to an overgrowth of algae or plants
some planst/algae die
decomposers increase using O2 (aerobic respiration)
fish die as oxygen decreases
Why is protein important for growth?
amino acids
hormones
bone
DNA
tissue
muscle
Suggest why it is important that water can circulate through the cages
circultaing water removes such as faeces and urine
prevents stagnation and disease/pollution
Suggest why fish farmers supply small amounts of food at regular intervals
so all the food is eaten and there is less waste
Suggest why fish farmers aim to have Food Conversion Efficiency
there is an economic benefit; there is more growth from a small amount of food
What is an intraspecific competition?
competition between members of the same species
What is an interspecific competition?
competition between differnt species
Describe ways in which fish farmers can reduce intraspecific competition?
increase the cage size so there is no overcrowding
supply enough food
Describe ways in which fish farmers can reduce interspecific competition?
only have one type of fish per cage
stop other fish entering the cage by separating the cages with mesh
Give one reason why dish are an important food source for humans?
fish are a source of protein
Give two ways in which fish farmers maintain water quality and how it is achieved
prevent build up of food by feeding in small, regular amounts
remove waste by filtering the water
Suggest five ways in which a fish farm might cause harm to the local ecosystem
release of waste
release of chemicals
release of bacetria
disease can infect wild fish
habitat destruction by floowing/building the fish farms
Give five advantages of fish farming compared to catching fish in the wild
guaranteed harvest
no need to buy boat or fuel
it is not dangerous
no depleteing wild fish stocks
no overfishing - conserves endagered species
Plan an investigation to compare the effect of two different types of fish food on the growth of fish
C: use different fish foods
O: same species and size of fish
R: several fish used
M: growth measured in mass
M: make the time period for the experiment more than one week
S: control the temperature and mass of food by regular feeding
Describe and explain three different ways a fish farmer can help to increse the yield of fish
protect from predators by covering ponds with nets
prevent disease by using antibiotics
control water quality by filtering out nitrogenous water
