TOPIC 1 Lesson 3

Ecosystems at a variety of scales.

Syllabus Link 1.1.2 - Apply the systems concept on a range of scales.

What do we mean by scales?

Global?Regional?National?

Local?

Ecosystems at Different Scales

We will look at Ecosystems that are at 3 separate scales:

1. GAIA – The “global” ecosystem.2. BIOME – Large / national scale ecosystem.3. POND – Local scale ecosystem.

• Gaia Intro 1 http://www.youtube.com/watch?v=xVGuRX0xNaI

• Gaia Intro2 http://www.youtube.com/watch?v=4tXfX4qpGjc up to 2:32

GAIA

• 1979 – James Lovelock “the Earth is a planet-sized organism, and the atmosphere is its organ that regulates it and connects all its parts”.

• He argued that the biosphere keeps the composition of the atmosphere within certain boundaries by negative feedback mechanisms.

Wider Reading: http://www.scienceclarified.com/Ex-Ga/Gaia-Hypothesis.html

Interactive Simulation: http://library.thinkquest.org/C003763/flash/gaia1.htm

His argument was based on:

• Earth’s surface temperature remains constant, even though the sun is emitting 30% more energy than when the Earth was formed.

• The composition of the atmosphere is constant (79% Nitrogen, 21% Oxygen, 0.03% CO2). Oxygen is a reactive gas but its proportion in the atmosphere doesn’t change.

• Ocean salinity is constant at around 3.4%.

The Biosphere

• Stretches from the bottom of the oceans to the lower layer of the atmosphere.

Biosphere

Hydrosphere

AtmosphereLithosphere

BIOME

“A large naturally occurring community of flora and fauna occupying a major habitat”

• Log on to www.worldbiomes.com as a starting point.

• What are the major biomes around the world?• Create a mind-map that covers all the major

types and sub-types, including examples and key characteristics.

http://www.youtube.com/watch?v=hIy0ZlyPPDg

LOCAL SCALE - POND

http://www.thewaterpage.com/pond-ecosystem.htm

Draw a system diagram for the pond here at KGV.You may wish to take photographs / make notes around the pond to bring back to help you.

Pond Ecosystem Diagram