ecology - trophic levels in an ecosystem

trophic levels

feeding levels within an ecosystem - can be represented by numbers

apex predators

carnivores with no predator

carne

meat

herb

plant

omni

plant and meat

vore

eater

lvl 1

plants and alga make their own food and are known as producers

lvl 2

herbivores that eat plant and alga = primary consumer

lvl 3

carnivores that eat herbivores = secondary consumers

lvl 4

carnivores that eat other carnivores = tertiary consumers

important role of decomposers in carbon cycle

break down dead plant and animal matter by secreting enzymes into environment. small soluble food molecules then diffuse into the microorganism

what are decomposers usually?

bacteria or fungi

key factors for creating optimum conditions for decay:

• presence of oxygen

• water

• warmth

• presence of microorganisms

biomass

amount of living material at each trophic level

what do pyramids of biomass show?

the relative amount of biomass in each level of a food chain

what is always at the bottom of a pyramid of biomass?

plant or alga

pyramid of biomass

why is the diagram a pyramid shape?

because the amount of biomass and energy available at each trophic level decreases

incident light

the light which shines in the producer

what are producers mostly?

plants and algae

how much incident energy do producers transfer from light for photosynthesis?

1%

what percentage of biomass from each trophic level is transferred to the level above it?

10%

reasons for loss of biomass: (3)

• not all ingested material is absorbed into the body some is egested as faeces

• not all the absorbed material is used to make new biomass some is lost as waste like Co2 and water in respiration and water and urea in urine

• large amounts of glucose are used up in respiration and provide energy for movement, growth and keeping a constant body temp.

use of glucose

1. used up in respiration

2. provides energy for:

• movement

• growth

• keeping body at constant temp

waste products

• carbon dioxide and water in respiration

• water and urea in urine

equation for efficiency of biomass:

effciency of biomass = (biomass transferred to the next level / biomass available at the previous level ) x 100