Notes 1 – Food Notes 1 – Food ChainsChainsSCI 10 EcologySCI 10 Ecology

Food ChainsFood ChainsGrassGrass grasshopper grasshopperrobinrobinhawkhawk

Producer: makes its own food through photosynthesis which uses energy from the sun

-Autotroph: auto = self, troph = food

Energy transfer (90% lost at each step)

-Primary Consumer: eat producers

-Herbivore: only eat plants

-Heterotrophs: hetero = others, troph = food

Secondary Consumer

Tertiary consumer

Other DefinitionsOther Definitions

Omnivore:Omnivore: eats everything (plants and meat) eats everything (plants and meat) Ex. Human, brown bearsEx. Human, brown bears

Carnivore:Carnivore: only eats meat only eats meat Ex. LionsEx. Lions

Scavengers:Scavengers: eat dead things eat dead things ex. Vultures, raccoonsex. Vultures, raccoons

Decomposers:Decomposers: consume dead material and consume dead material and recycle (return) nutrients to the soilrecycle (return) nutrients to the soil ex: worms, bacteria, fungiex: worms, bacteria, fungi

Trophic LevelsTrophic Levels

First trophic level = producers (plants)First trophic level = producers (plants) Second trophic level = primary Second trophic level = primary

consumers (herbivores)consumers (herbivores) Third trophic level = secondary Third trophic level = secondary

consumers (carnivores)consumers (carnivores) Fourth trophic level = tertiary consumersFourth trophic level = tertiary consumers

In which trophic level do In which trophic level do each of the following each of the following organisms belong?:organisms belong?:

grassgrass crowcrow coyotecoyote Maple treeMaple tree bacteriabacteria snakesnake mousemouse deerdeer porcupineporcupine red squirrelred squirrel seedsseeds

ProducersProducers Primary Primary consumersconsumers

Secondary Secondary consumers/consumers/

DecomposersDecomposers

EnergyEnergy

What is the primary source of energy for What is the primary source of energy for all food chains? all food chains? The sun – without it we would not have foodThe sun – without it we would not have food

Food Web: Food Web: many food chains many food chains interlinkedinterlinked Identify 3 food chains in the food web Identify 3 food chains in the food web

belowbelowdeer

grass

shrubs

insect

frog

hawk

snake wolf

rabbit

mouse

Abiotic vs. bioticAbiotic vs. biotic

Abiotic factors: Abiotic factors: non-living non-living Ex: soil, water, a rock, sun Ex: soil, water, a rock, sun

Biotic factors: Biotic factors: living or was livingliving or was living Ex: trees, birds, insects, bacteriaEx: trees, birds, insects, bacteria

Complete the diagram using the following terms : Complete the diagram using the following terms : primary consumer (herbivore) , secondary consumer primary consumer (herbivore) , secondary consumer (carnivore), tertiary consumer, decomposers, second trophic (carnivore), tertiary consumer, decomposers, second trophic level, first trophic level, producer, fourth trophic level, third level, first trophic level, producer, fourth trophic level, third trophic leveltrophic level

Transfer of EnergyTransfer of Energy

-Food energy ingested by a consumer is -Food energy ingested by a consumer is used for many processes used for many processes

Only around ____ % is converted into Only around ____ % is converted into body mass. body mass.

Why do we rarely see more than 4 links Why do we rarely see more than 4 links in a food chain?in a food chain?

Because energy decreases along the chain and Because energy decreases along the chain and so higher level consumers can’t be supportedso higher level consumers can’t be supported

Organisms are Organisms are interconnectedinterconnected

Look at the following food chain :Look at the following food chain :

Grass Grass deer deer wolf wolf

If the deer population increases, what If the deer population increases, what would happen towould happen to::

The grass population?The grass population? The wolf population?The wolf population?

The grass population would decreaseThe grass population would decrease The wolf population would increase The wolf population would increase

because:because: More food increases reproductive rates (more More food increases reproductive rates (more

babies)babies) Eventually, the wolf population would start to Eventually, the wolf population would start to

decrease because food would run out decrease because food would run out

DefinitionsDefinitions

Ecosystem:Ecosystem: interactions among interactions among organisms and their environmentorganisms and their environment

Biotic factors:Biotic factors: components of an components of an ecosystem that are, or use to be, livingecosystem that are, or use to be, living

i.e.:i.e.:

Abiotic factors:Abiotic factors: components of an components of an ecosystem that are non-livingecosystem that are non-living

i.e.:i.e.:

p.14 – Copy the Pyramid p.14 – Copy the Pyramid Fig 1.8Fig 1.8

The greatest amount of energy is in the The greatest amount of energy is in the _______________, that of the _______________, that of the _______________._______________.

A pyramid of numbers A pyramid of numbers is used to is used to represent the number of organisms at represent the number of organisms at each trophic level each trophic level

The ___________ are the organisms that The ___________ are the organisms that are usually the most numerousare usually the most numerous

p.15 p.15

Look at this pyramid: Look at this pyramid: Which 2 organisms are most numerous?Which 2 organisms are most numerous?

p.16 – Copy Fig 1.11p.16 – Copy Fig 1.11

___________ combines the number and ___________ combines the number and size of organisms size of organisms It indicates how much living matter there is It indicates how much living matter there is

in a particular organism in a particular organism

A pyramid of biomassA pyramid of biomass: shows the : shows the biomass at each trophic levelbiomass at each trophic level

Which trophic level has the greatest biomass?Which trophic level has the greatest biomass? Which trophic level has the smallest biomass?Which trophic level has the smallest biomass?

p.17 – Copy Fig 1.13p.17 – Copy Fig 1.13

A A pyramid of energy flowpyramid of energy flow shows the shows the total chemical energy at each trophic total chemical energy at each trophic levellevel

Total energy decreases from producers Total energy decreases from producers to consumers – how?to consumers – how?

90% of the energy from your food is lost to: 90% of the energy from your food is lost to: respiration, heat production, waste production respiration, heat production, waste production

10% of the energy from your food is used to 10% of the energy from your food is used to produce new tissues and grow produce new tissues and grow

Calculate the Energy Calculate the Energy Transferred at Each Trophic Transferred at Each Trophic LevelLevel

Look at the following food chain :Look at the following food chain :

Grass Grass Rabbit Rabbit Snake Snake Wolf Wolf Complete the table belowComplete the table below

Grass receives 7400 kilojoules (kJ) or energy from the sunGrass receives 7400 kilojoules (kJ) or energy from the sun

OrganismOrganism Available energy Available energy (kJ)(kJ)

Energy used (kJ)Energy used (kJ) Energy stored (kJ)Energy stored (kJ)

Notes 1 QuestionsNotes 1 Questions

1.1. Which type of organism is at the beginning of all Which type of organism is at the beginning of all food chains?food chains?

2.2. Which organisms can eat all other organisms ?Which organisms can eat all other organisms ?

3.3. In an ecosystem, the abiotic factors includeIn an ecosystem, the abiotic factors include…?…?

4.4. 3 examples of decomposers are …?3 examples of decomposers are …?

5.5. What is the importance of decomposers in an What is the importance of decomposers in an ecosystem?ecosystem?

6.6. What is the principal source of energy for all What is the principal source of energy for all ecosystems?ecosystems?