Chapter 3: The Biosphere

Chapter 3 Outline

3-1: What is Ecology?3-2: Energy Flow3-3: Cycles of Matter

3-1: What is Ecology?

Interactions and InterdependenceLevels of OrganizationEcological Methods

Interactions and Interdependence

Ecology – the scientific study of interactions among organisms and between organisms and their environment

Biosphere – The combined portions of the planet in which all life exists.

Levels of Organization in Biology

Levels of Organization

Species – groups of organisms that can breed and produce fertile offspring.

Population – group of organisms of the same species that live in the same area

Community – all the living organisms found in an area.

Ecosystem – all the organisms that live in a place, along with their environment.

Biome – group of ecosystems that have the same climate and similar dominant communities.

Biosphere – the combined portions on Earth where living things are found.

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Ecologists study the environment in 3 ways:

ObservingExperimentingModeling

3-2: Energy Flow

Producers Energy From the Sun Energy Without Light

ConsumersFeeding Relationships

Food Chains Food Webs Trophic Levels

Ecological Pyramids

ProducersEcosystems need a source of energy to survive.

For most ecosystems, the main source of energy is the Sun.

Energy!

For a few ecosystems, it comes from chemical energy from the earth.

Like at this deep sea vent!

Chemosynthesis:

Carbon dioxide + hydrogen sulfide carbohydrates + sulfur

Energy!

Producers

A producer is an organism (like plants, algae or bacteria) that produces its own food Chemosynthesis – energy from inorganic chemical

compounds is used to make food (some bacteria) Photosynthesis – energy from the Sun is used to make food

(plants, algae, some bacteria)

Producers are autotrophs because they make their own food.

Consumer

A consumer is an organism that eats another organism

Another word for consumer: heterotroph

Types of consumers(heterotrophs):

1. Herbivores obtain energy from eating producers (autotrophs)

2. Carnivores eat herbivores or other heterotrophs.

3. Omnivores obtain energy from eating both autotrophs and heterotrophs.

4. Detritovores obtain energy from eating plant and animal remains (detritus)

5. Decomposers obtain energy from organic matter (things that were once alive).

Energy can be tracked throughout the ecosystem through feeding relationships

Food Chain

A food chain is a series of steps in which organisms transfer energy by eating and being eaten.

Food Web

A food web is the network of complex interactions formed by the feeding relationships among the various organisms in an environment.

Food Web

Each step in a food chain or a food web is called a trophic level.

Food Web

A food web shows all the possible feeding relationships in an ecosystem.

How are food chains and food webs the same?

How are they different?

Only 10% of the energy is transferred to each trophic

level.

Energy loss can be measured in biomass of organisms.

Energy loss and biomass comparison

Energy flows one way in an ecosystem:Producers 1st Level Consumers 2nd Level Consumers 3rd Level Consumers

3-3: Cycles of Matter

Recycling in the BiosphereThe Water CycleNutrient Cycles

The Carbon Cycle The Nitrogen Cycle The Phosphorus Cycle

Nutrient Limitation

Recycling in the Biosphere

Unlike energy, matter is recycled within and between ecosystems.

Matter is passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles.

Condensation

Seepage

Runoff

Precipitation

TranspirationEvaporation

RootUptake

Section 3-3The Water Cycle

The Water Cycle

1. Water can enter the atmosphere by evaporation and transpiration1. Evaporation – water changing from a liquid to a

gas.2. Transpiration – water evaporating through tree

leaves.

2. Water cools in the air and condenses into clouds.

3. Water falls to the ground as precipitation.4. Water makes its way to the ocean by runoff.

Nutrient Cycles

A nutrient is a substance an organism needs to sustain life.

Some common nutrients are: Carbon (C) Nitrogen (N) Phosphorous (P)

Carbon

Important for: Living tissue Animal skeletons Photosynthesis Cellular respiration

Co2

Released into the atmosphere by: Breathing, volcanoes, burning trees & fossil fuels

Absorbed by: Oceans, Plants (esp. trees, algae),

CO2 inAtmosphere

CO2 in Ocean

Section 3-3

The Carbon Cycle

Found in the air, and in dead things and poop: N2 = nitrogen gas – 78% of the atmosphere – unable to be used by

producers NH3 = ammonia NO3

- = nitrate found in dead things, able to be used by living things NO2

- = nitrite

Important for: Making proteins

Some bacteria convert nitrogen gas into ammonia using nitrogen fixation, so producers can use them.

N2 NH3

Some bacteria convert nitrates back into nitrogen gas using denitrification.

NO3- N2

Nitrogen

N2 in Atmosphere

NH3

NO3-

and NO2-

Section 3-3The Nitrogen Cycle

Phosphorous

Important for: Making nucleic acids (DNA, RNA)

NOT found in the atmosphere Mostly found in rocks and soil minerals, and in ocean

sediments.

Nutrient Limitation

primary productivity – the rate at which organic matter is created by producers

When an ecosystem has low primary productivity because it doesn’t have enough of a single nutrient, we call that a limiting nutrient. A common limiting nutrient is phosphorous (P).

Limiting Nutrient