Chapter 4:Ecosystems: Components,

Energy Flow, and Matter Cycling

“The Earth’s thin film of living matter is sustained by grand-scale cycles of energy

and chemical elements.”G. Evelyn Hutchinson

What Is Ecology

The study of how organisms interact with one another and with their nonliving environment.

Connections in nature

Important Terminology (Biology Review)

OrganismAny form of life

CellEukaryotic cellProkaryotic cell

SpeciesGroups of organisms

PopulationGroup of interacting individuals of the same species that occupy a specific area at the same time

Genetic DiversityVariance in genetic makeup of populations

HabitatWhere a population normally lives

Levels Of Organization

Earth’s Systems

AtmosphereTroposphere/Stratosphere

HydrosphereLiquid water

Ice, icebergs, frozen soil layers

Water vapor

LithosphereCrust and upper mantle

BiosphereWhere living organisms exist

Life On Earth

Life depends on three interconnected factors

1. One-way flow of high-quality energy from the sun

2. Cycling of Matter

3. Gravity

Interconnected Factors

Ecosystem Concepts and Biomes

Terrestrial portion of the biosphere has been classified into biomes.

These biomes are characterized by:Distinct climate

• Long-term patters of weather

Specific landforms

Characteristics of Ecosystems

No distinct boundaries nor self-contained

Abiotic FactorsRange of tolerance

Limiting factor

Biotic FactorsProducers – autotrophs

Consumers - heterotrophs • Herbivores Carnivores

• Omnivores Scavengers

• decomposers

Food Webs and Energy Flow

Food Chain Food Web

Pyramids of Energy Flow

Biogeochemical Cycles

Nutrient cycles – the nutrient atoms, ions, and molecules that organisms need to live, grow, and reproduce are continuously cycled from the nonliving environment and then back again.

Water Cycle

Water Cycle – Human Impacts

Withdrawing large quantities of fresh water from streams, lakes, and underground sources.

Clearing vegetation from land for agriculture, mining, road and building construction, and other activities.

Modifying water quality

Carbon Cycle

Carbon Cycle – Human Impacts

Clearing trees and other plants that absorb CO2 through photosynthesis

Adding large amounts of CO2 by burning fossil fuels and wood

Nitrogen Cycle

Nitrogen Cycle – Human Impacts

Adding large amounts of nitric acid into the atmosphere when we burn any fuel.

Adding nitrous oxide to the atmosphere through the action of anaerobic bacteria on livestock wastes and commercial inorganic fertilizers

Removing nitrogen from topsoil

Phosphorous Cycle

Phosphorous Cycle – Human Impacts

Mining large quantities of phosphate rock for use in commercial inorganic fertilizers and detergents

Reducing the available phosphate in tropical forests by removing trees.

Adding excess phosphate to aquatic ecosystems:

Runoff of animal wastes

Runoff of commercial phosphate

Discharge of municipal sewage

Sulfur Cycle

Sulfur Cycle – Human Impact

Burning sulfur-containing coal and oil

Refining sulfur-containing petroleum

Using smelting to convert sulfur compounds of metallic minerals

Ecosystem Services

“All things come from earth, and to earth they all return.

Menander (342-290 B.C.)