*Read the entire board!*Note change to homework!!!! Please have your homework on your desk for a stamp

Yo!*

Comparative Niches

Share with your neighbor!Find the strongest comparison in the group.Statement: Even though ecosystems are

different, they need to have the same niches. Agree or disagree? Defend your choice!

Energy flow in ecosystems

Energy Pyramid

Fig. 4–16

• ecological efficiency 5% to 20%

• 10% efficiency general rule

© Brooks/Cole Publishing Company / ITP

Graphic representation of energy available at each trophic level.

90% energy is lost in transfer between trophic levels: motion, body heat, metabolism, growth

10% Rule: Only 10% of energy is available to next trophic level.

Energy pyramids – key understandings

Fig. 4–17

© Brooks/Cole Publishing Company / ITP

Explain why there are no more than 5 or 6 links in a food chain.

Give us our language “lower/higher” on the food chain.

Can NEVER be “upside” downExplain why top predators like wolves need

lots of land to find enough food to survive.

Prairie Ecosystem

Hawks

Snakes

Mice

Grasses

Our food chain – which would provide more total calories for 7 billion

people?

human

animals

plants

human

plants

Biomass Pyramids measure mass

Fig. 4–18© Brooks/Cole Publishing Company / ITP

Pyramids of Numbers

Fig. 4–19

© Brooks/Cole Publishing Company / ITP

A measure of the rate at which autotrophs store biomass.

Net primary productivity = photosynthetic rate of plants – respiration rate of plants.

Primary Productivity determines the shape of the pyramids’ base (and then the next levels up)

Net Primary Productivity

Primary Productivity (per area)

Fig. 4–21© Brooks/Cole Publishing Company / ITP

Check for understanding!

Key understandings of energy pyramidsWhere does 90% of the energy go?How to calculate energy at each level (units?)Exceptions to numbers and biomass pyramids