ecology (food chains and pyramids)

what is needed to carry out life processes?

energy

definition of autotrophs (or producers)

they are living organisms which converts light energy to chemical energy, which is stored in food molecules

definition of consumers

they cannot make their own food so they obtain energy by feeding on other organisms

what are the 2 types of consumers

1. primary consumers

2. secondary consumer

what are primary consumers

organisms which feed directly on plants

what are consumers

carnivores which feed on herbivores and other smaller animals

definition of decomposers

breakdown dead organisms, faeces and nitrogenous waste (urea in urine) and enables the materials (C, O, N, H) locked up in the dead organisms to be returned to the physical environment

what are food chains

a series of organism through which energy is transferred in materials form

what are food webs

many food chains linked together to form a food web

what are trophic levels

each stage in a food chain

a group of organisms that share the same feeding position in a food chain

what must the each trophic level be?

1st: producer

2nd: primary consumer

3rd: secondary consumer (carnivore)

4th: tertiary consumer (top carnivore)

how is energy lost along the food chain?

1. metabolic waste and faeces through defacaetion and excretion

2. respiration (by producers, consumers, decomposers)

3. trapped and present in dead organisms

how does a pyramid of number usually look like? and what relationships does this represent

broad base and narrow towards the apex

feeding relationship

how does an unusual pyramid of number look like? what relationship does this represent?

the pyramid has a narrow base and becomes broader towards the apex

parasitic relationship

characteristics of a parasite

1. much smaller in size compared to its host

2. lives in or on host and bring harm to the host

3. multiply and reproduce very fast

4. population size is much larger than host

what is biomass

the total dry mass of a population, which represents the total amount of living material present at a particular time

(theoretical mass)

what does a pyramid of biomass looks like

it has a standard broad base, narrow towards the top shape

what is an anomaly in pyramid of biomass?

it is when a small organism multiplies very rapidly to replace the organisms consumed by a consumer

so, at one time, the fast multiplying organism will appear to be smaller in number (since it reproduces very fast and is immediately consumed by the next tropic levels)

what is the function of a pyramid of energy

compared the amount of energy passing through each trophic level over a period of time

what are the pros and cons of a pyramid of energy

pros: most reliable representation

cons: difficult to obtain since it requires knowing:

1. how much of all the different foodstuffs are manufactured by the producer?

2. how much energy they contain?

3. how much of each foodstuff is passed onto each member of the food web?

why is a food chain unsustainable when it is more than 4 trophic levels`

energy lost at each trophic level results in insufficient energy to support higher trophic levels

so the top carnivore needs to consume a lot of organisms to obtain enough energy for survival

characteristics of the energy flow

non-cyclic

the ultimate source of energy is from the sun

(the dead body [arts of living organisms, egressed and excreted materials contains trapped energy. this energy released by respiration. eventually, all energy that enters the food chain or food web is released as heat energy into the surroundings)

what processes drive carbon cycle?

1. respiration

2. combustion of wood

3. photosynthesis

4. decomposition by bacteria

what processes releases CO2 into air?

1. decomposition → dead bodies decayed by microorganisms and decomposers respires and oxidises organic material in the carcasses

2. respiration

3. combustion

what processes removes CO2 from the air?

photosynthesis

which processes converts the most amount of carbon in the carbon cycle?

photosynthesis

3 processes contributing Co2 yet only 1 removes

yet Co2 is stable

importance of carbon cycle

1. continuous supply of CO2 for photosynthesis

   1. P converts energy form Sun to energy in teh food, which other non-photosynthetic organisms can use to stay alive

2. enables energy to flow through the ecosystem since carbon compounds carry the trapped solar energy form organisms to organisms in the food chains of an ecosystem

what is a carbon sink?

areas that store carbon compounds for an indefinite period. they remove CO2 from the air and reduces the rate of global warming

what are 2 examples of carbon sinks

oceans and forests

how do oceans sore carbon?

photosynthesis and solubility

1. CO2 that dissolves in the oceans water is absorbed and use by photyplankton and algae in photosynthesis

   1. a portion of C compounds in oceans is buried in the seabed in the form of fossil fuels such as natural gas and oil

why is adding iron compounds to water a pro

1. overall increase in food supply

   1. improve the state of the oceans as fish stocks (many of which have been suffering from decades of overfishing) might improve

2. removes more Co2 from the atmosphere as Fe fertilisation increases plant population and increases photosynthetic rates

why is adding iron compounds to the water a con

1. fertilised waters favour less useful pathways in the food web, causing the jellyfish and algae populations to increase, leading to harmful algal blooms and eutrophication → submerged plants and animals are harmed up the food chain

how do forests act as carbon sinks

1. atmospheric carbon dioxide is absorbed by the plants and used in photosynthesis

   1. large amounts of carbon compounds is stored in trees. when trees die, their remains may be buried in the ground → these remains form coal millions of years later

why is deforestation harmful

there will be a reduction in carbon sinks needed to maintain a constant atmospheric carbon dioxide

what is a predator

organisms that hunt

what is a prey

organisms that is hunted and eaten and is food for the predator

what are the cycle of predator-prey characteristics

1. increase and decrease in population of predator follows the corresponding increase and decrease in the population of its prey

2. the average size of the prey is larger than that of the predator

what’s the cycle of pre and predator

1. increase in populations of prey means that there is more food available for the predator

2. an increase in number predator occurs

3. a decrease in prey population drops due to increased predation

4. decrease in predators population as less food is available

5. decrease in predator allows an increase in the number of prey

what are 3 assumptions made in the prey predator relaitosup

that the predator has no other sources of food except the prey

that the prey has no other predator except for the predator

changes In population do not take into consideration of death that occurs due to diseases or sickness

how does adding iron compounds help carbon absorption efficiency

it increases photosynthetic activity of phytoplankton → increases carbon dioxide absorption efficiency as a higher rate of P causes CO2 to be removed at a faster rate