EcologyEcology

Biology Chapter 3Biology Chapter 3

EcologyEcology

The scientific study of The scientific study of interactions among interactions among organisms and their organisms and their environmentenvironment

Biotic vs. AbioticBiotic vs. Abiotic Biotic FactorsBiotic Factors

Living organismsLiving organismsExample: plants, animals, Example: plants, animals, bacteria, etc.bacteria, etc.

Abiotic FactorsAbiotic FactorsNon-living factorsNon-living factors

Examples: Temperature, air Examples: Temperature, air currents, moisture, light, soil, etc.currents, moisture, light, soil, etc.

OrganismOrganism

Individual Individual belonging to a belonging to a species species

All organisms All organisms depend on depend on other other organisms for organisms for survivalsurvival

SpeciesSpecies

Species—organisms with similar Species—organisms with similar anatomical features that can anatomical features that can interbreed and produce fertile interbreed and produce fertile offspring. offspring.

PopulationPopulation

A group of A group of organisms of organisms of one species one species that live in the that live in the same same geographic geographic areaarea

CommunityCommunity

A group of A group of different different populations populations that lives in the that lives in the same same geographic geographic areaarea

EcosystemEcosystem

A collection of A collection of all the organisms all the organisms that live in a that live in a particular place, particular place, together with together with their nonliving their nonliving environmentenvironment

BiomeBiome

A group of A group of ecosystems that ecosystems that have the same have the same climate and climate and dominant dominant communitiescommunities

Types:Types: TerrestrialTerrestrial AquaticAquatic

BiosphereBiosphere

The combined The combined portions of portions of Earth in which Earth in which all living all living things exist things exist (land, water, (land, water, air, air, atmosphere)atmosphere)

Summary of Levels Summary of Levels of Organizationof Organization

BiosphereBiomeEcosystemCommunityPopulationOrganism

To sum it up…To sum it up… Ecology is all about relationships!Ecology is all about relationships!

How do organisms relate to each other How do organisms relate to each other within a population?within a population?

How do populations relate to each other How do populations relate to each other within a community?within a community?

How do communities relate to each other How do communities relate to each other within an ecosystem? How do they relate within an ecosystem? How do they relate to their environment?to their environment?

Remember, relationships can be Remember, relationships can be beneficial or harmful!beneficial or harmful!

EnergyEnergySunlight is the main source of energy for life on Earth

Less than 1 % of all the sun’s energy that reaches Earth’s surface is used by living things.

Other sources of energyOther sources of energy

Some organisms make food from Some organisms make food from inorganic chemical compounds inorganic chemical compounds

Ex: Archaebacteria undergo Ex: Archaebacteria undergo chemosynthesis and obtain nutrients chemosynthesis and obtain nutrients from mineral water from hot springsfrom mineral water from hot springs

AutotrophsAutotrophs

AutotrophsAutotrophs are also called are also called producersproducers

Organisms that capture energy from Organisms that capture energy from sunlight or chemicals to produce food. sunlight or chemicals to produce food.

This is done either by photosynthesis or This is done either by photosynthesis or chemosynthesis. chemosynthesis.

Ex: plants, algae, certain bacteriaEx: plants, algae, certain bacteria

HeterotrophsHeterotrophs

Heterotrophs Heterotrophs are also called are also called

consumers.consumers. Organisms that rely on other Organisms that rely on other

organisms for their energy and food organisms for their energy and food supply. supply.

Ex: animals, fungi (decomposers), Ex: animals, fungi (decomposers), protists, certain bacteriaprotists, certain bacteria

Types of heterotrophsTypes of heterotrophs HerbivoresHerbivores—obtain energy from eating —obtain energy from eating

plantsplants Carnivores—Carnivores—obtain energy from eating obtain energy from eating

animalsanimals Omnivores—Omnivores—obtain energy from eating both obtain energy from eating both

plants and animalsplants and animals Detrivores—obtain energy from feeding Detrivores—obtain energy from feeding

on animal and plant remainson animal and plant remains Decomposers—break down organic Decomposers—break down organic

matter ex: bacteria and fungimatter ex: bacteria and fungi

Energy flowEnergy flow

Energy flows through an ecosystem in Energy flows through an ecosystem in one direction, from the sun (or inorganic one direction, from the sun (or inorganic compounds) to producers, to consumers. compounds) to producers, to consumers.

Food ChainFood Chain

Energy stored by producers is passed Energy stored by producers is passed through an ecosystem along a food through an ecosystem along a food chain. chain.

Food chain—Food chain—a series of steps in which a series of steps in which organisms transfer energy by eating and organisms transfer energy by eating and being eaten. being eaten.

Food Chain Food Chain

Food WebFood Web

Feeding relationships are usually more Feeding relationships are usually more complex than can be shown in a food complex than can be shown in a food chain. chain.

Food web—Food web—when feeding relationships when feeding relationships form a network of interactions. form a network of interactions.

Food WebFood Web

Trophic LevelsTrophic Levels

Trophic level—Trophic level—Each step in a food chain Each step in a food chain or food web or food web

Producers make up the first trophic Producers make up the first trophic level. Consumers make up the level. Consumers make up the second, third, or higher levels. second, third, or higher levels.

Consumers depend on the trophic Consumers depend on the trophic level below it for energylevel below it for energy

Ecological PyramidsEcological Pyramids

Ecological Pyramids—Ecological Pyramids—a diagram that a diagram that shows the relative amounts of energy or shows the relative amounts of energy or matter contained in each trophic level of matter contained in each trophic level of a food chain or food web. a food chain or food web.

Energy PyramidEnergy Pyramid

Only about 10% of energy available within one trophic level is transferred to organisms at the next trophic level. The rest is spent for life processes (like respiration, movement, and reproduction), some of the remaining energy is lost as heat

Biomass PyramidBiomass Pyramid

The total amount of living tissue within a trophic level is biomass.

Pyramid of NumbersPyramid of Numbers

Pyramids can also be based on the numbers of organisms at each trophic level.

Cycles of MatterCycles of Matter

Unlike the one-way flow of energy, matter is Unlike the one-way flow of energy, matter is recycled between ecosystems. recycled between ecosystems.

This recycling is accomplished by This recycling is accomplished by Biogeochemical Cycles.Biogeochemical Cycles.

Biogeochemical CyclesBiogeochemical Cycles recycle the same recycle the same molecules around again and again. You are molecules around again and again. You are made of molecules that are millions or billions made of molecules that are millions or billions of years old!of years old!

The Water CycleThe Water Cycle

All life requires liquid water. All life requires liquid water. Water moves between the living things, the ocean, the Water moves between the living things, the ocean, the

atmosphere, and land. atmosphere, and land.

EvaporationEvaporation—when water changes from liquid —when water changes from liquid form to gasform to gas

TranspirationTranspiration—When water enters the —When water enters the atmosphere by evaporating from the leaves of atmosphere by evaporating from the leaves of plants. plants.

CondensationCondensation—When water vapor turns into tiny —When water vapor turns into tiny liquid droplets. liquid droplets.

Water Cycle DiagramWater Cycle Diagram

NutrientsNutrients

NutrientsNutrients—All of the chemical —All of the chemical substances that an organism substances that an organism needs to sustain life. needs to sustain life.

The Carbon CycleThe Carbon Cycle Biological processes—photosynthesis, Biological processes—photosynthesis,

respiration, and decomposition take up and respiration, and decomposition take up and release Carbon and Oxygen. release Carbon and Oxygen.

Geochemical processes—volcanic activity and Geochemical processes—volcanic activity and erosion release COerosion release CO22

Due to decomposition and pressure over time, Due to decomposition and pressure over time, Carbon is stored underground (fossil fuels)Carbon is stored underground (fossil fuels)

Mining, burning forests and fossil fuels release Mining, burning forests and fossil fuels release CO2 back into the atmosphereCO2 back into the atmosphere

Carbon Cycle DiagramCarbon Cycle Diagram

The Nitrogen CycleThe Nitrogen Cycle

All organisms require nitrogen to make All organisms require nitrogen to make amino acids, which make proteins. amino acids, which make proteins.

Nitrogen gas makes up 78% of the Nitrogen gas makes up 78% of the Earth’s atmosphere. Earth’s atmosphere.

Ammonia (NH3), nitrates, and nitrites are Ammonia (NH3), nitrates, and nitrites are found in the wastes produced by found in the wastes produced by organisms and is decaying organic organisms and is decaying organic matter. matter.

The Nitrogen Cycle The Nitrogen Cycle Only certain types of bacteria can use nitrogen Only certain types of bacteria can use nitrogen

gas directly. These bacteria live in soil and on gas directly. These bacteria live in soil and on the roots of plants. the roots of plants.

Nitrogen fixation—Nitrogen fixation—The process by which The process by which bacteria convert nitrogen gas into ammoniabacteria convert nitrogen gas into ammonia

Other bacteria convert the ammonia into Other bacteria convert the ammonia into nitrates and nitrites, which producers use to nitrates and nitrites, which producers use to make proteins. Consumers get nitrogen from make proteins. Consumers get nitrogen from eating producers. eating producers.

Nitrogen Cycle DiagramNitrogen Cycle Diagram

The Phosphorous CycleThe Phosphorous Cycle

Phosphorous is needed to help form Phosphorous is needed to help form DNA and RNA. DNA and RNA.

Phosphorous is released into the Phosphorous is released into the atmosphere when rocks and sediments atmosphere when rocks and sediments wear down over time. wear down over time.

Plants absorb phosphates from soil or Plants absorb phosphates from soil or water, and consumers get phosphates water, and consumers get phosphates from eating plants. from eating plants.

Phosphorous Cycle Phosphorous Cycle DiagramDiagram

Community InteractionsCommunity Interactions

Interactions between organisms Interactions between organisms have a huge impact on ecosystems. have a huge impact on ecosystems.

Community InteractionsCommunity Interactions Types of interactions:Types of interactions:

Competition—when organisms attempt to Competition—when organisms attempt to use a resource in the same place at the use a resource in the same place at the same time.same time. Competitive exclusion principle—Competitive exclusion principle—no two no two

species occupy the same niche in the same species occupy the same niche in the same habitat. habitat.

PredationPredation—an interaction where one —an interaction where one organism captures and feeds on another organism captures and feeds on another organismorganism

More interactionsMore interactions

SymbiosisSymbiosis—a relationship in which —a relationship in which two species live closely together. two species live closely together.

Usually one species lives on or Usually one species lives on or inside of another. inside of another.

One species always benefits and One species always benefits and other can be harmed, helped, or other can be harmed, helped, or have no effect. have no effect.

Types of SymbiosisTypes of Symbiosis Mutualism—Mutualism—a symbiotic relationship in a symbiotic relationship in

which both species benefit. Ex: Flowers which both species benefit. Ex: Flowers and the insects that pollinate them.and the insects that pollinate them.

Commensalism—Commensalism—a symbiotic relationship a symbiotic relationship in which one species benefits and the other in which one species benefits and the other is unaffected.is unaffected. Ex: barnacles on a whaleEx: barnacles on a whale

ParasitismParasitism—a symbiotic relationship —a symbiotic relationship where one species benefits and the other where one species benefits and the other is harmed. Ex: Fleas, ticks, tapeworms is harmed. Ex: Fleas, ticks, tapeworms and their hosts. and their hosts.

Types of SymbiosisTypes of Symbiosis..The acacia tree and Pseudomyrmex ants are an example of mutualism

Types of SymbiosisTypes of Symbiosis..

An epiphyte plant is an example of commensalism

Types of SymbiosisTypes of Symbiosis..A tapeworm is an example of a parasite

Ecological SuccessionEcological Succession

Ecological Succession—Ecological Succession—The series of The series of predictable changes that occurs in a predictable changes that occurs in a community over time. community over time.

As an ecosystem changes, older species As an ecosystem changes, older species gradually die out and new species move gradually die out and new species move in. in.

Types of SuccessionTypes of Succession

Primary Succession—Primary Succession—When succession When succession occurs on surfaces where no soil exists. occurs on surfaces where no soil exists. Ex: after a volcanic eruption builds a new Ex: after a volcanic eruption builds a new island or covers land with lava rock. island or covers land with lava rock.

Secondary Succession—Secondary Succession—When a When a disturbance changes an ecosystem disturbance changes an ecosystem without removing the soil. Ex: a forest without removing the soil. Ex: a forest after a fire. after a fire.

SuccessionSuccession

Climax Community—an older, Climax Community—an older, established community that is no longer established community that is no longer changing (as much)changing (as much)

PopulationsPopulations

Population Density—The Population Density—The number of individuals per unit number of individuals per unit areaarea

Ex: number of dandelions per Ex: number of dandelions per mm22

Population GrowthPopulation Growth Several factors affect population Several factors affect population

size:size: Births— # of organisms born Births— # of organisms born Deaths— # of organisms that dieDeaths— # of organisms that die Immigration—The movement of Immigration—The movement of

organisms organisms intointo a population a population Emigration—The movement of Emigration—The movement of

organisms organisms out out of a populationof a population

Exponential GrowthExponential Growth

Unrestricted populations of Unrestricted populations of organisms experience organisms experience exponential growth. exponential growth.

Must have unlimited resources Must have unlimited resources

Exponential Growth Exponential Growth GraphGraph

Logistic growthLogistic growth As resources become less As resources become less

available, population growth available, population growth slows or stops (birth rate=death slows or stops (birth rate=death rate) This is called leveling off.rate) This is called leveling off.

Carrying capacity—Carrying capacity—The The maximum number of organisms maximum number of organisms that the environment can support that the environment can support

Logistic growth graphLogistic growth graph

Limiting factorsLimiting factors

Limiting factor—a factor that Limiting factor—a factor that causes population growth to causes population growth to decrease. decrease.

Density-Dependent Density-Dependent factorsfactors

Density-Dependent factors—Density-Dependent factors—limiting factors whose effects limiting factors whose effects increase as the size of the increase as the size of the population increasespopulation increases

Ex: Ex: Competition, predation, Competition, predation, parasitism, diseaseparasitism, disease

Density-Independent Density-Independent factorsfactors

Density-Independent factors—Density-Independent factors—Limiting factors that affect all Limiting factors that affect all populations in similar ways, populations in similar ways, regardless of population size and regardless of population size and densitydensity

ExEx: Natural disasters, seasonal : Natural disasters, seasonal cycles, certain human activitiescycles, certain human activities

Human populationsHuman populations

Demography—Demography—The scientific The scientific study of human populationsstudy of human populations

Exponential Growth in Exponential Growth in our human populationour human population

Since the industrial revolution of Since the industrial revolution of the 1800s the human population the 1800s the human population has been experiencing has been experiencing exponential growth. exponential growth.

Effects of increased Effects of increased growth growth

If the human population continues If the human population continues to grow at an exponential rate this to grow at an exponential rate this could cause:could cause: Starvation and death for millionsStarvation and death for millions Some countries to set limits on birth Some countries to set limits on birth

ratesrates

Slowing population Slowing population growthgrowth

Human population growth can be Human population growth can be slowed by:slowed by: Global epidemics (influenza, HIV, Global epidemics (influenza, HIV,

etc.)etc.)

Limiting birth ratesLimiting birth rates

BiodiversityBiodiversity

Biodiversity—Biodiversity—the total variety of the total variety of organisms in the biosphere. organisms in the biosphere.

It is important to preserve It is important to preserve biodiversity for a variety of biodiversity for a variety of reasons (food webs, new reasons (food webs, new medicine, etc.)medicine, etc.)

Maintaining biodiversityMaintaining biodiversity

Humans can help maintain Humans can help maintain biodiversity by: biodiversity by:

Enforcing the Endangered Species Enforcing the Endangered Species ActAct

Making laws protecting the Making laws protecting the wilderness (including rainforests)wilderness (including rainforests)

Destroying BiodiversityDestroying Biodiversity

Humans can destroy biodiversity Humans can destroy biodiversity by:by:

Habitat destructionHabitat destruction Introducing invasive speciesIntroducing invasive species

(ex: Zebra mussels in Great Lakes, (ex: Zebra mussels in Great Lakes, rabbits in Australia, etc.) rabbits in Australia, etc.)

The Greenhouse effectThe Greenhouse effect

The Greenhouse effect—The Greenhouse effect—Water vapor and greenhouse Water vapor and greenhouse

gases (CO2, methane, etc.) trap gases (CO2, methane, etc.) trap heat from the sun in our heat from the sun in our atmosphere. This keeps Earth atmosphere. This keeps Earth warmer, like the glass panels of warmer, like the glass panels of a greenhouse. a greenhouse.

Global WarmingGlobal Warming

Global Warming—Global Warming—An increase An increase in greenhouse gases which in greenhouse gases which increases the amount of heat increases the amount of heat trapped in Earth’s atmosphere. trapped in Earth’s atmosphere.

Human activities causing Human activities causing global warmingglobal warming

Burning fossil fuels and cutting Burning fossil fuels and cutting down the rainforests are down the rainforests are increasing greenhouse gases increasing greenhouse gases (especially CO2), which is most (especially CO2), which is most likely causing global warming. likely causing global warming.

Air PollutionAir Pollution

The quality of our air is important The quality of our air is important to our health. Burning fossil to our health. Burning fossil fuels and factory emissions fuels and factory emissions being released into the air being released into the air contribute to air pollution. contribute to air pollution.