Goals for Chapter 2 (2.1)

• design and analyse experiments on the effects of altering biotic or abiotic factors (e.g., nutrients in soil: compare two plant types with the same nutrients, compare one plant type with different nutrients)

• explain various relationships with respect to food chains, food webs, and food pyramids, including

– producer – consumer (herbivore, carnivore, omnivore) – predation (predator‐prey cycle) – decomposers – symbiosis (mutualism, commensalism, parasitism)

• identify the effects on living things within an ecosystem resulting from changes in abiotic factors, including

– climate change (drought, flooding, changes in ocean current patterns, extreme weather)

– water contamination – soil degradation and deforestation

Vocabulary

BiodegradationConsumers

DecomposersFood chain

Food pyramidFood webProducers

Trophic levels

2.1 Energy Flow in Ecosystems

• ______________ is the total mass of all living things in a given area. (measured in g/m2 or kg/m2)

• Organisms interact with the ecosystem by:

1. Obtaining __________ from the ecosystem

2. Contributing _____________ to the ecosystem

Energy Flow in Ecosystems

– Plants are called ______________ because they make carbohydrates (sugars) during photosynthesis.

CO2 + H2O + sunlight C6H12O6 + O2

– _______________________ get their energy by feeding on producers or other consumers.

- ______________ break-down wastes & dead organisms, through the process of biodegradation, into USUALBLE nutrients

Reading Check Page 59

Energy Flow & Energy Loss in Ecosystems

• Methods to represent _____________ moving through ecosystems.– ___________ ______________: show the flow of energy

in an ecosystem.– ____________ ______________: represent

interconnected food chains. They model the feeding relationships in an ecosystem

– ___________ ______________: show the changes in available energy from one trophic level to another in a food chain. They’re also called ecological pyramids

Food Chains• Each step is a trophic level

– ______________

= 1st trophic level– ________ consumers

= 2nd trophic level– ________ consumers

= 3rd trophic level– ________ consumers

= 4th trophic level

Terrestrial & aquatic food chains

• Consumers in a food chain can be classified as:1.________________________ - obtain energy &

nutrients from dead organisms & waste matter (not the same as decomposers!!). they have their own, separate food chains &

they feed on every trophic level. Eg. small insects, earthworms, bacteria

2._______________ - primary consumers eat plants (producers) only Ex. Horse eating hay

This dung beetle is a detrivore.

3. ________________ - secondary or tertiary consumers Secondary consumers eat non-producers

(herbivores)• Eg. Frog eating a grasshopper

Tertiary consumers eat secondary consumers • also called top predators, top

carnivores or top consumers • Eg. Lions eating humans

4. ___________ - consumers that eat both • plants & animals• Eg. include humans and bears

Detrivores and Decomposers• _____________________ (worms, millipedes, dung

flies, beetles) eat dead material (typically includes the bodies or fragments of dead organisms as well as fecal material), but don't actually break it down to its inorganic components. They leave behind a considerable amount of unused energy and nutrients. They essentially just increase the surface area to make it easier for decomposers to do their work.

• __________________ (fungi and bacteria) take what's left when detrivores are done and actually break it down into its inorganic parts/nutrients/minerals.

Food Webs

This food web represents a terrestrial ecosystem that could be found in British

Columbia.

• Most organisms are part of many food chains.– Arrows in a ________

_______ represent the ____ ___ ____________ and nutrients (from more energy to less energy).

– Following the arrows _________ to the top carnivore(s).

Cool Food Chain Video

http://www.youtube.com/watch?v=TE6wqG4nb3M

Food Pyramids• Energy enters at the first tropic level

(producers), where there is a large amount of ____________ & therefore a lot of energy

• It takes large quantities of organisms in one tropic level to meet the energy needs of the next trophic level.

•80% - 90% of energy taken in by consumers is used in chemical reactions in the body, or is lost as heat energy.

•Therefore only about ______________ of energy in an organism is ___________ _______ to the next organism when eaten

The amount of life an ecosystem can sustain is based on the bottom level of the _____________ ____________, where producers capture energy from the sun.

• Lower trophic levels have much larger populations than upper levels.

• This shows the importance of maintaining large, _______________________

populations at the lowest levels of the food pyramid.

Reading Check Page 64

2.1 Summary

• Biomass (total amount of biotic stuff)• Energy Flow:

– Make energy (producers/decomposition/biodegradation)– Use energy (consumers)

• Food chain/ trophic levels: Primary producers, primary consumers, secondary consumers, tertiary consumers

• Detrivores• Herbivores, carnivores, omnivores • Food webs• Food pyramids/ecological pyramid (different types: # of

types of organisms, loss of energy, # of organisms x mass)