trophic levels

what do organisms need energy for?

life function

how is solar energy used?

• cell resp releases it

• photosynthesis captures + stores it

how much energy reaches earth?

10²² joules

where does 30% of the energy reaching earth go?

reflected from the clouds due to albedo

albedo

amount of reflected energy

why do clouds reflect energy?

light and shiny = higher albedo, vice versa = lower albedo

where does 19% of the energy reaching earth go?

absorbed by water vapor and carbon dioxide in the atmosphere

where does 51% of the energy reaching earth go?

reaches the surface and warms the planet

where does 1-2% of the energy reaching earth go?

used for photosynthesis

autotrophs

harness solar energy to photosynthesize in order to create energy

chemoautotrophs

use energy from inorganic chemicals to convert carbon in carbs with sunlight

• done by bacteria + fungi

heterotrophs

consume other organisms for energy

primary heterotroph

herbivores eat autotrophs

secondary heterotroph

carnivores eat herbivores

tertiary heterotroph

consumers eat other consumers

decomposers

breaks down waste from dead organisms for energy

how does the cycle repeat w decomposers

returns all matter, air, and water to the soil which is used by autotrophs

what is the first law of thermodynamics?

energy is not created/destroyed, only transformed/transferred

what is the second law of thermodynamics?

energy is lost in every conversion as unusable heat, less is available from the next

ecology

study of ecosystems

ecosystem

community of living things (biotic) interacting with non living things (abiotic)

any examples of abiotic factors?

water, minerals, climate, sun, etc.

trophic levels

feeding levels where energy and matter transfers in the chain

what is important when understanding where an animal lies on the chain?

• they can coexist in more than one trophic level

• what eats it

• what it eats

food chain

linear pathway of food transfer from producer → consumer

food web

energy transfer among multiple food chains

how is energy distributed in food chains?

• 10% moves up

• 90% becomes unusable heat

ecological pyramids

quantitative relationships between trophic levels

pyramid of numbers

based on # of organisms @ each trophic level

general trend for pyramid of numbers?

MOST but not all ecosystems, higher trophic level = less organisms

inverse pyramid of numbers

higher trophic level = more organisms

when are inverse pyramid of numbers used?

when a smaller # of large organisms can support smaller organisms

• this is bc more biomass at lower levels

pyramid of biomass

based on biomass of organisms on each trophic level

what does the pyramid of biomass measure?

relative dry mass (g/s²) of living and dead organisms

general trend for pyramid of biomass?

MOST but not all ecosystems, higher trophic level = less biomass available

• less energy too

inverse pyramid of biomass

higher trophic level = more biomass

pyramid of energy

based on total # of energy in each trophic level

how much energy moves up in a pyramid of energy

• usually 10%, but can be anywhere between 5% and 20%

general trend in pyramid of energy?

ALL ecosystems, higher trophic level = less energy

inverse pyramid of energy

does not exist

biomagnification

higher trophic level = higher concentration of toxins

what kind of system is earth?

no matter enters/leaves, but energy can (closed system)

how does energy flow in the biosphere?

energy flows one way through biosphere (sun → plant → animal → heat)

why does matter cycle?

recycle matter to be used again