PACKET #33 CHAPTER #13 Ecosystems & The Flow of Energy & Matter.

PACKET #33CHAPTER #13

Ecosystems &The Flow of Energy &

Matter

Introduction

Ecosystem Encompasses all the interactions among organisms

living together in a particular place, and among those organisms and their abiotic environments

Individual communities and their abiotic environments Earth, which encompasses the biosphere (all of

Earth’s communities) and its interaction with Earth’s water, soil, rock and atmosphere, is the largest ecosystem

ENERGY FLOW

Ecosystems

Energy Flow Through Ecosystems

The flow of energy is linear—as energy cannot be reused by organisms Energy begins as solar energy, which is trapped by

photosynthesis in the form of chemical energy Chemical energy is then available to do work

Energy Flow II

Energy flow describes who eats whom in ecosystems A food chain describes

the sequential passage of energy

A food web shows the complexity of interconnected food chains Remember that a food

web is composed of many food chains

Energy Flow III

Food Chain Refresher Primary producers are

autotrophs and comprise the first trophic level

Herbivores, primary consumers, comprise the second trophic level May find omnivores here

Carnivores and/or omnivores, comprise trophics level three and higher all the way to the decomposers

Energy Flow IV

Ecological Pyramid Illustrates the trophic

levels May be a pyramid of

Numbers

Energy Flow V

Ecological Pyramid Illustrates the trophic

levels May be a pyramid of

Biomass

Energy Flow VI

Ecological Pyramid Illustrates the trophic

levels May be a pyramid of

Energy

Cycles of Matter in Ecosystem

Introduction

Biochemical cycles are cycles of matter between the abiotic and biotic components of the environment

Carbon, nitrogen, phosphorus and water cycles are central to life on earth

Carbon, nitrogen and water cycles have atmospheric components and cycle on a global scale

Carbon Cycle

Carbon dioxide is the pivotal molecule in the carbon cycle

Human activities, since the beginning of the Industrial Revolution, have contributed an increasing amount of carbon dioxide to the atmosphere by burning fossil fuels

Nitrogen Cycle

Bacteria are essential to this cycle Nitrogen fixing bacteria

converts nitrogen gas to ammonia

Nitrifying bacteria converts ammonia to nitrate

Denitrifying bacteria converts, anaerobes, convert nitrate to nitrogen gas

Nitrogen is needed for the production of proteins

Nitrogen oxides are also an ingredient in photochemical smog

Phosphorus Cycle

Fertilizers, runoff containing animal wastes, and sewage introduce phosphorus into aquatic ecosystems

Phosphorus loss accelerated by clear cutting Brazil

Water Cycle

Enough said!

Review