13-1 “Ecology: Studying 13-1 “Ecology: Studying Nature’s Houses”Nature’s Houses”

Objective:Objective:Define the term ecology.Define the term ecology.Explain ecology’s importance Explain ecology’s importance

as a scientific field of study.as a scientific field of study.

Ecological ResearchEcological Research

Ecology is:Ecology is: Study of interactions between Study of interactions between

organismsorganisms Study of interaction between Study of interaction between

organisms and their environmentorganisms and their environment

ObservationsObservations

Advantages: Often lead to valuable Advantages: Often lead to valuable understanding of situations and understanding of situations and phenomena; Often suggest connections phenomena; Often suggest connections between various events in nature.between various events in nature.

Disadvantage: Alone cannot prove those Disadvantage: Alone cannot prove those links.links.

ExperimentsExperiments

Advantages: Allow control of variables Advantages: Allow control of variables and the chance to manipulate each and the chance to manipulate each variable.variable.

Disadvantage: In the lab it’s difficult to Disadvantage: In the lab it’s difficult to recreate complex relationships found in recreate complex relationships found in nature.nature.

Why Study Ecology?Why Study Ecology?

Gives us information necessary to Gives us information necessary to understand and resolve many of understand and resolve many of the environmental and ecological the environmental and ecological issues that confront us.issues that confront us.

Web of InterdependenceWeb of Interdependence

Living things affect each other in many Living things affect each other in many ways.ways.

The process of acquiring energy and The process of acquiring energy and nutrients joins all life together.nutrients joins all life together.

Organisms need energy to power life’s Organisms need energy to power life’s processes and raw materials to build and processes and raw materials to build and maintain living tissue.maintain living tissue.

13-2 Ecology & Energy: 13-2 Ecology & Energy: Essential for Life’s ProcessesEssential for Life’s Processes

Objective: Objective: Describe how energy flows through Describe how energy flows through

the biosphere & different trophic the biosphere & different trophic levels.levels.

Define the terms consumer, Define the terms consumer, producer, heterotroph, autotroph, producer, heterotroph, autotroph, carnivore, omnivore, parasite & carnivore, omnivore, parasite & decomposer.decomposer.

What organisms can harness What organisms can harness energy from sunlight?energy from sunlight? Green Plants, Algae, some Green Plants, Algae, some

BacteriaBacteria By what process?By what process?

PhotosynthesisPhotosynthesis

Energy From the SunEnergy From the Sun

PrimaryPrimary ProducersProducers

AutotrophsAutotrophs ““self-feeders”self-feeders” Create food from water, COCreate food from water, CO2 2

and sunlight and sunlight Produce all of the food for all Produce all of the food for all

organismsorganisms

ConsumersConsumers

HeterotrophsHeterotrophs ““different food”different food” Must consume food produced by Must consume food produced by

the producersthe producers

HeterotrophsHeterotrophs

HerbivoresHerbivores obtain energy by eating obtain energy by eating autotrophs (mostly plants)autotrophs (mostly plants)

CarnivoresCarnivores obtain energy by eating obtain energy by eating other animals (meats)other animals (meats)

OmnivoresOmnivores are animals who eat both are animals who eat both plants and animals.plants and animals.

HeterotrophsHeterotrophs

ParasitesParasites are organisms that live in or on are organisms that live in or on other organisms and obtain their other organisms and obtain their nutrients from their living host.nutrients from their living host.

DecomposersDecomposers feed on the dead bodies of feed on the dead bodies of animals and plants or on their waste animals and plants or on their waste products.products.

Energy Flow Through the Energy Flow Through the BiosphereBiosphere

Energy can neither be created Energy can neither be created nor destroyed!nor destroyed!

(Law of Thermodynamics)(Law of Thermodynamics)

Energy Flow Through the Energy Flow Through the BiosphereBiosphere

•Energy flows from the sun to producers to consumers.

•All energy on Earth comes from the sun.

Trophic LevelsTrophic Levels Fig. 13-6, p.288Fig. 13-6, p.288

Each step in a food chain or food webEach step in a food chain or food web More levels = less energyMore levels = less energy 90% of energy is lost at each level90% of energy is lost at each level Usually no more than 5 trophic levelsUsually no more than 5 trophic levels Decomposers fit in everywhereDecomposers fit in everywhere

Ecological PyramidsEcological Pyramids Fig. 13-7, p.290Fig. 13-7, p.290

Diagram how energy and nutrients Diagram how energy and nutrients decrease as you move up the trophic decrease as you move up the trophic levels. levels.

13-3 Nutrients: Building Blocks 13-3 Nutrients: Building Blocks of Living Tissueof Living Tissue

Objectives:Objectives: What are nutrients?What are nutrients? Describe how nutrients are re-cycled in Describe how nutrients are re-cycled in

the biosphere. (Water, Nitrogen and the biosphere. (Water, Nitrogen and Carbon)Carbon)

Nutrient LimitationNutrient Limitation

What are nutrients?What are nutrients?

The chemical building blocks of The chemical building blocks of life.life.

The substances that organisms use The substances that organisms use to build living tissues and to grow.to build living tissues and to grow.

Autotrophs make complex Autotrophs make complex substances such as carbohydrates, substances such as carbohydrates, fats, and proteins from simple fats, and proteins from simple nutrients that they can easily get nutrients that they can easily get from their environmentfrom their environment

(ex. Water, carbon dioxide, nitrogen, (ex. Water, carbon dioxide, nitrogen, phosphorus, and potassium).phosphorus, and potassium).

How do autotrophs obtain How do autotrophs obtain nutrients?nutrients?

Heterotrophs must eat other organisms Heterotrophs must eat other organisms to obtain nutrients.to obtain nutrients.

Fats and carbohydrates provide Fats and carbohydrates provide immediate energy or are stored in the immediate energy or are stored in the animal’s body.animal’s body.

Proteins are broken down into amino Proteins are broken down into amino acids, which are used to build the acids, which are used to build the animal’s proteins.animal’s proteins.

How do heterotrophs obtain How do heterotrophs obtain nutrients?nutrients?

Where does all energy on Earth Where does all energy on Earth come from?come from?

Light energy from the sun.Light energy from the sun.

Heat energy.

How do heterotrophs release How do heterotrophs release energy?energy?

Nutrient CyclesNutrient Cycles

Matter can not be created nor Matter can not be created nor destroyed.destroyed.

We only have what is present on We only have what is present on the Earth.the Earth.

Nutrients must be recycled.Nutrients must be recycled.

Examples of Nutrient CyclesExamples of Nutrient Cycles

WaterWater CarbonCarbon

NitrogenNitrogen

Water CycleWater Cycle

Carbon Carbon CycleCycle

Nitrogen CycleNitrogen Cycle

N2 in Atmosphere

NH3

NO3-

and NO2-

Nutrient LimitationNutrient Limitation

The size of a community depends on The size of a community depends on the amount of food produced by the the amount of food produced by the autotrophs.autotrophs.

Certain nutrients are scarce, so they Certain nutrients are scarce, so they limit plant growth.limit plant growth. This is why farmers use fertilizer.This is why farmers use fertilizer.

13-4 Food Webs: Who Eats 13-4 Food Webs: Who Eats Whom?Whom?

Describe a food web.Describe a food web.

Food Chains and WebsFood Chains and Webs

Food chain – simple diagram showing Food chain – simple diagram showing who eats whowho eats who

Food web – combination of all food Food web – combination of all food chains in a communitychains in a community Shows complexity of feeding Shows complexity of feeding

relationshipsrelationships

Coastal Salt Coastal Salt Marsh Food Marsh Food

WebWeb

13-5 The Carbon Cycle: A 13-5 The Carbon Cycle: A Closer LookCloser Look

The Greenhouse EffectThe Greenhouse Effect The increase in warming effect on Earth.The increase in warming effect on Earth. Greenhouse gases (ex. Carbon dioxide) trap energy Greenhouse gases (ex. Carbon dioxide) trap energy

in the atmosphere as heat.in the atmosphere as heat. Later heat radiates back into outer space.Later heat radiates back into outer space. BUT carbon dioxide and other gases absorb some BUT carbon dioxide and other gases absorb some

of this heat energy forming a “heat trap” around the of this heat energy forming a “heat trap” around the Earth.Earth.

4 Major Carbon Pathways4 Major Carbon Pathways

1. Biological Pathways1. Biological Pathways Photosynthesis, respiration, and death and decay of plants Photosynthesis, respiration, and death and decay of plants

and animals.and animals. 2. Geochemical Pathways2. Geochemical Pathways

Release of carbon dioxide to atmosphere by volcanic Release of carbon dioxide to atmosphere by volcanic activities, weathering of rocks, and exchange of carbon activities, weathering of rocks, and exchange of carbon dioxide between the ocean and atmosphere.dioxide between the ocean and atmosphere.

3. Biogeochemical Pathways3. Biogeochemical Pathways Burial and conversion of carbon from dead organisms Burial and conversion of carbon from dead organisms

into coal and petroleum.into coal and petroleum.

4. Human-initiated Pathways4. Human-initiated Pathways Mining, burning of fossil fuels, and cutting and Mining, burning of fossil fuels, and cutting and

burning of forests.burning of forests.

Experimental DataExperimental Data

Carbon flows between 3 major carbon reserviors.Carbon flows between 3 major carbon reserviors. Oceans, atmosphere, and deposits in the Earth.Oceans, atmosphere, and deposits in the Earth.

Although the amount of carbon entering the Although the amount of carbon entering the atmosphere as a result of human activity is atmosphere as a result of human activity is relatively small, its cumulative effect in the future relatively small, its cumulative effect in the future can be significant.can be significant.

Atmospheric Carbon Dioxide Atmospheric Carbon Dioxide LevelsLevels

Gradual increase in atmospheric carbon dioxide Gradual increase in atmospheric carbon dioxide levels is probably due to human activity.levels is probably due to human activity.

As the insulating layer of carbon dioxide gets As the insulating layer of carbon dioxide gets thicker, it could have a warming effect on Earth.thicker, it could have a warming effect on Earth.