What Shapes an Ecosystem? Abiotic and Biotic Factors, Community Interactions

• Write “Updates to 90-93 and Food Web Notes” on new page– Record clarifying info about pages 90-93 (part 1 –

minimal notes)– Takes notes on food webs (part 2)– USE YOUR NOTES TODAY TO ANSWER

QUESTIONS!

The “niche”• What is a niche?

– Full range of abiotic and biotic conditions in which an organism lives – and how it uses these conditions

– Biotic = living– Abiotic = nonliving

Niche example• Example: cane toad niche

– How the cane toad interacts with all biotic/abiotic factors – for example: • Bodies of water cane toads inhabit as tadpoles• What shelter they use on land as adults• The climate/type of ecosystem they survive in best• How/when they reproduce• What they eat and what eats them• Etc…

• Note: no two species occupy the same exact niche! Brainstorm: why not?

• Competition! One species wins, one loses (leaves the niche, evolves, or goes extinct) eventually – might take time

Competition • Could be competition for ANY type of resource

– Sun, water, food, space, nutrients, etc…• What is it? What is an example in your ecosystem jar?• Record ecosystem jar example

Predation• Predation: An interaction in which one organism

captures and feeds on another organism.• What is it? What is an example in your

ecosystem jar?• Record ecosystem jar example

Symbiosis

• Symbiotic relationship– A relationship in which two species live closely

together.• 3 main classes of symbiosis – what are they?

– Mutualism– Commensalism– Parasitism

Mutualism• What is it? What is an example in your

ecosystem jar?• Mutualism: Win-Win• Example: Shrew Loo• Record ecosystem jar example

Commensalism• What is it? What is an example in your

ecosystem jar?• Commensalism: Win-neutral• Example: Anemonefish• Record ecosystem jar example

– Snails laying eggs on Elodea

Parasitism• What is it? Is there an example in your ecosystem jar?• Symbiosis – when one species benefits and other is

harmed – but not really predation (win-lose)– Differs in that parasites often live in or on the host

• Example: Parasitic wasp

Food Webs (new notes!)• Usually represent predation in an ecosystem

– Show how biomass & energy move in ecosystems– Shows relationships between producers

(autotrophs) and consumers (heterotrophs)• Why are they useful?

– Orcas and salmon – enough to support Orcas?– Humans – enough food to support us?– What if organism(s) are removed? Predictions…– Easier than reading lots of papers (visual)

• Example food web – ecosystem jars!– Build now – show organisms

Energy in food webs (in 3-2)• Energy: ability to do work (NOT matter/material)

– Light energy (helps producers create food)– Chemical energy (light converted to chem in food)– Thermal energy (chem converted to “waste” heat)

• All energy begins at the producer level– Can move its way up a food web

• Brainstorm – why do consumers have about 10% of the energy available from organisms they consume?

• The remainder (90%) is: – 1) kept by producers– 2) lost as waste (thermal or chemical)– All life processes produce chemical and thermal waste– Show on food web now

Biomass in food webs (in 3-2)• Biomass: living material in an ecosystem (in

grams, usually)• All biomass begins at the producer level

– Moves its way up a food web• Do consumers retain all biomass they

consume?• No –Only about 10% gets to next level (rest is

kept or lost as waste – liquid, solid, gaseous)– Show on food web now

Energy vs. Matter

• Energy is NOT matter– Energy is stored in matter, can be released as

matter is broken down/metabolized– Plants store energy by making glucose/food– All organisms use/release energy by

consuming/breaking down food