5.1: Communities Topic 5: Ecology & Evolution Miss Friedman.

5.1: Communities5.1: Communities

Topic 5: Ecology & EvolutionTopic 5: Ecology & Evolution

Miss FriedmanMiss Friedman

5.1.1: Definitions5.1.1: Definitions

EcologyEcologyThe study of the relationship between living The study of the relationship between living

organisms and between those organisms organisms and between those organisms and their environmentand their environment

EcosystemEcosystemA community and its abiotic environmentA community and its abiotic environment

PopulationPopulationA group of organisms of the same species who A group of organisms of the same species who

live in the same area at the same timelive in the same area at the same time

5.1.1: Definitions5.1.1: Definitions

CommunityCommunityPopulations of different species in the same Populations of different species in the same

area which are interactingarea which are interacting

SpeciesSpeciesA group of organisms which can interbreed A group of organisms which can interbreed

and produce fertile offspringand produce fertile offspring

HabitatHabitatLocation within which a species normally livesLocation within which a species normally lives

5.1.2: Autotrophs & 5.1.2: Autotrophs & heterotrophsheterotrophs

AutotrophAutotroph ProducerProducer An organism that An organism that synthesises its synthesises its organic molecules organic molecules from simple inorganic from simple inorganic moleculesmolecules

HeterotroHeterotrophph

consumerconsumer Obtains organic Obtains organic molecules from other molecules from other organismsorganisms

5.1.3: Consumers, detritivores, 5.1.3: Consumers, detritivores, saprophytessaprophytes

ConsumersConsumersAn organism that ingests other organic matter An organism that ingests other organic matter

that is living or recently deadthat is living or recently dead

DetritivoresDetritivoresAn organism that ingests non-living organic An organism that ingests non-living organic

mattermatter

SaprophytesSaprophytesAn organism that lives on or in non-living An organism that lives on or in non-living

organic matter, secreting digestive enzymes organic matter, secreting digestive enzymes into and absorbing the products of digestioninto and absorbing the products of digestion

5.1.4: Food chains5.1.4: Food chains

►Food chains show a simple linear flow of Food chains show a simple linear flow of “who eats who” “who eats who”

►Therefore shows the energy flowing Therefore shows the energy flowing through the links in the chainthrough the links in the chain

Questions to consider!Questions to consider!

How is energy lost in the chain?How is energy lost in the chain?

Why are big, dangerous predators so rare?Why are big, dangerous predators so rare?

5.1.5: Food webs5.1.5: Food webs► A diagram that shows how food chains are A diagram that shows how food chains are

linked together into more complex feeding linked together into more complex feeding relationshipsrelationships

Advantages over food chainAdvantages over food chaino Shows much more complex interactions between Shows much more complex interactions between

species within a community/ecosystemspecies within a community/ecosystemo More than one producer supports a communityMore than one producer supports a communityo A single producer is a food source for many primary A single producer is a food source for many primary

consumersconsumerso A consumer might have a number of different food A consumer might have a number of different food

sources on the same/different trophic levelssources on the same/different trophic levelso A consumer can be an omnivore, feeding as a primary A consumer can be an omnivore, feeding as a primary

consumer but also as a consumer at higher tropic levelsconsumer but also as a consumer at higher tropic levels

5.1.6: Trophic level5.1.6: Trophic level► The tropic level of an organism defines the The tropic level of an organism defines the

feeding relationship of that organism to feeding relationship of that organism to other organisms in a food webother organisms in a food web

AutotraphAutotraph ProducerProducer Tropic level Tropic level 11

HetertrophHetertroph Primary consumerPrimary consumer Tropic level Tropic level 22

HetertrophHetertroph Secondary Secondary consumerconsumer

Trophic level Trophic level 33

heterotropheterotrophh

Tertiary consumerTertiary consumer Trophic level Trophic level 44

5.1.7: Determining tropic 5.1.7: Determining tropic levels in food chains/webslevels in food chains/webs

►Assign tropic Assign tropic levels to the levels to the food web on food web on the right!the right!

5.1.8: Constructing a food 5.1.8: Constructing a food webweb

►Producers are usually shown at the Producers are usually shown at the bottombottom

►Use full name of organismsUse full name of organisms►Arrows show the movement of matter Arrows show the movement of matter

& energy& energy

5.1.9:Light & food chains5.1.9:Light & food chains

►Sunlight is the source of energy for Sunlight is the source of energy for most communities, both aquatic and most communities, both aquatic and terrestrialterrestrial

►Very few communities deep in the Very few communities deep in the ocean use geothermal energyocean use geothermal energy

5.1.10: Energy flow in Food 5.1.10: Energy flow in Food chainchain

► a) a) Not all solar energy will come Not all solar energy will come into contact with chlorophyll and into contact with chlorophyll and will therefore not be trapped in will therefore not be trapped in the synthesis of organic the synthesis of organic compoundscompounds

► b)b) PhotosynthesisPhotosynthesis► c)c) Consumers feeding and Consumers feeding and

passing on energy in the food passing on energy in the food ► d)d) Loss of energy as heat from Loss of energy as heat from

respirationrespiration► e)e) death and the consumption of death and the consumption of

dead organisms by detritivores. dead organisms by detritivores. Or as food not assimilated Or as food not assimilated because of incomplete digestion.because of incomplete digestion.

Energy LossEnergy Loss► loss of energy in undigested food loss of energy in undigested food

which will then be used by which will then be used by saprophytes/ decomposerssaprophytes/ decomposers

► loss of heat energy in the loss of heat energy in the reactions of respirationreactions of respiration

► ultimately all energy will be lost ultimately all energy will be lost has heathas heat

5.1.11: Efficiency of energy 5.1.11: Efficiency of energy transformationstransformations

►When energy is When energy is changed from one changed from one form into another, form into another, it is never 100% it is never 100% efficientefficient

► Approximately Approximately only 10-20% of the only 10-20% of the energy on one energy on one trophic level will trophic level will be assimilated at be assimilated at the next higher the next higher trophic leveltrophic level

5.1.12: Shape of energy 5.1.12: Shape of energy pyramidspyramids

►A A pyramid of energypyramid of energy is a graphical is a graphical representation of the amount of energy of representation of the amount of energy of each trophic level in a food chaineach trophic level in a food chain

►The units are kJ/mThe units are kJ/m22/yr/yr►The narrowing shape illustrates the gradual The narrowing shape illustrates the gradual

loss of energy processing along the links of loss of energy processing along the links of a food chain to higher trophic levelsa food chain to higher trophic levels

5.1.13: Energy and matter 5.1.13: Energy and matter in ecosystemsin ecosystems

► Energy is NOT recycled through the ecosystemEnergy is NOT recycled through the ecosystem► Energy is constantly received from the sun and Energy is constantly received from the sun and

constantly radiates out in the form of light & heatconstantly radiates out in the form of light & heat►Matter IS recycledMatter IS recycled► The process of recycling nutrients requires energyThe process of recycling nutrients requires energy

5.1.14: Decomposers5.1.14: Decomposers► Two main groups are Two main groups are detritivoresdetritivores (e.g. (e.g.

earthworms, dung beetles) and earthworms, dung beetles) and saprotrophssaprotrophs (e.g. fungi, bacteria)(e.g. fungi, bacteria)

►Decomposition is a complex process and Decomposition is a complex process and serves many functions; formation of soil, serves many functions; formation of soil, recycling of nutrients, reduction of high recycling of nutrients, reduction of high energy carbon compoundsenergy carbon compounds

►Organic molecules are oxidized to release Organic molecules are oxidized to release nitrogen in the form of nitrate, nitrite, and nitrogen in the form of nitrate, nitrite, and ammoniaammonia

►Oxidation of organic compounds provides Oxidation of organic compounds provides energy for saprophyte but returns matter to energy for saprophyte but returns matter to abiotic environmentabiotic environment