Topic 6: Topic 6: EcologyEcology
I. Parts of an EcosystemI. Parts of an EcosystemII. Population DynamicsII. Population Dynamics
Study of how organisms Study of how organisms INTERACTINTERACT with living and with living and
non-living thingsnon-living things
What is it?What is it?
What will we be looking at?What will we be looking at?
Parts of an ecosystemParts of an ecosystem Things that affect pop’n sizeThings that affect pop’n size Roles and relationships in an ecosystemRoles and relationships in an ecosystem Energy flow in an ecosystemEnergy flow in an ecosystem Importance of biodiversityImportance of biodiversity SuccessionSuccession Human impacts on the environmentHuman impacts on the environment
Ecosystem describes any portion of the
ENVIRONMENT
(ie. Decaying log, a pond, fish tank,
field of corn)
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The
environment
is every living and nonliving thing that surrounds an organism
Biotic FactorsBiotic Factors
ECOSYSTEM
Abiotic FactorsAbiotic Factors
ECOSYSTEMECOSYSTEM
What makes up an What makes up an ecosystem?ecosystem?
1. 1. BIOTIC FACTORSBIOTIC FACTORS• “Bio” means living• LIVING things in an
ecosystem• ie.PLANTS, ANIMALS, BACTERIA• Can you list the living
things that could live in this ecosystem?• Frogs, insects, fish, Frogs, insects, fish,
hawks, grasses, hawks, grasses, bacteria, amoeba bacteria, amoeba etc……..etc……..
2. ABIOTIC FACTORS2. ABIOTIC FACTORS• When you put “a” When you put “a”
in front of a word it in front of a word it negates itnegates it
• Means Means “NON-“NON-LIVINGLIVING” ” factorsfactors
• Can you list some Can you list some non-living factors non-living factors that affect the that affect the pond ecosystem?pond ecosystem?•WATER, LIGHT, WATER, LIGHT, TEMPTEMP, acidity, , acidity, oxygen and oxygen and nitrogen levelsnitrogen levels
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Ecological Levels of Ecological Levels of the Organization of the Organization of LifeLife
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Collectively all of the Collectively all of the Earth’s ecosystems Earth’s ecosystems make up the make up the
biospherebiosphere
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The specific environment in which
organisms live is their habitat
Ecosystem - populations in a community and the abiotic factors with which they interact (ex. Biomes)
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All the different populations are combined to form a
community
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All the organisms of a species that live in the same area, produce fertile offspring, and compete with each other for resources (food, mates, shelter, etc.) make up a
population
Organism - any unicellular or multicellular form exhibiting all of the characteristics of life, an individual.
•The lowest level of organization
Ecological Levels of the Ecological Levels of the Organization of LifeOrganization of Life• BIOSPHEREBIOSPHERE
• HABITAT (BIOME)HABITAT (BIOME)
• ECOSYSTEMECOSYSTEM
• COMMUNITYCOMMUNITY
• POPULATIONPOPULATION
• ORGANISMORGANISM
DecreasiDecreasing ng
amount amount of biotic of biotic
and and abiotic abiotic factorsfactors
What affects population sizes in an ecosystem?What affects population sizes in an ecosystem?• COMPETITION!COMPETITION!
• Struggle for Struggle for resources resources among among organismsorganisms
• If no competition, If no competition, populations would populations would grow grow INFINITELYINFINITELY (no (no limit!)limit!)
• Competition Competition maintains maintains FINITEFINITE (limited) pop’n sizes(limited) pop’n sizes• Finite populations Finite populations
limited by limited by LIMITING LIMITING FACTORSFACTORS• CAN BE ABIOTIC CAN BE ABIOTIC
OR BIOTICOR BIOTIC
Let’s look….Comparing Finite Let’s look….Comparing Finite and Infinite Populationsand Infinite Populations
INFINTITEINFINTITE GROWTHGROWTH
FINITE FINITE GROWTHGROWTH
What affects What affects population sizes in an population sizes in an
ecosystem?ecosystem?A) ABIOTIC LIMITING FACTORSA) ABIOTIC LIMITING FACTORS
Amount and intensity of Amount and intensity of SUNLIGHTSUNLIGHT Amount of Amount of WATERWATER Amount of dissolvedAmount of dissolved OXYGEN OXYGEN
(lakes, rivers, etc)(lakes, rivers, etc) Acid levelAcid level TEMPERATURETEMPERATURE rangerange MINERALSMINERALS available available
What affects population sizes in an What affects population sizes in an ecosystemecosystem??
B) BIOTIC LIMITING FACTORS•PREDATOR/PREYPREDATOR/PREY relationships
• Predators limit prey population sizes by eating them
• Prey limit predator population sizes by dying/being killed • If too many killed, predators starve• Adapting (survival of the best
adapted)
Let’s take a look…. Effects of Predator/Prey RelationshipLet’s take a look…. Effects of Predator/Prey Relationship
As you can see, AS PREY POPULATION AS PREY POPULATION DECREASES, THE PREDATOR’S POPULATION DECREASES, THE PREDATOR’S POPULATION DECREASES (DECREASES (Direct relationshipDirect relationship))
What do we call it when a species reaches its What do we call it when a species reaches its limit?limit?
• EVERY population in an ecosystem has a EVERY population in an ecosystem has a CARRYING CARRYING CAPACITY (K)CAPACITY (K)
• THE # OF ORGANISMS OF A SINGLE SPECIES AN THE # OF ORGANISMS OF A SINGLE SPECIES AN ECOSYSTEM CAN SUPPORTECOSYSTEM CAN SUPPORT• Determined by Determined by BIOTICBIOTIC and and ABIOTICABIOTIC factorsfactors
• EX:EX: a fox population is affected by how much it a fox population is affected by how much it has to eat (biotic) and also temperature has to eat (biotic) and also temperature (abiotic)(abiotic)
• Once K is reached, population will remain Once K is reached, population will remain stable stable unless major changes in biotic and abiotic factorsunless major changes in biotic and abiotic factors
Carrying Capacity (K) of a Stable Carrying Capacity (K) of a Stable PopulationPopulation
Part 2: POPULATION INTERACTIONS
How organisms interact in an ecosystem!
What role are you up for?
Competitive Exclusion PrincipleCompetitive Exclusion Principle
• If two different species compete for the same food source or reproductive sites, one species may be eliminated.
• This establishes one species per niche in a community.
A. What does it mean to have a role in an ecosystem?
NICHE:NICHE:• THETHE ROLEROLE (NOT SPACE!!!!!)(NOT SPACE!!!!!) AN AN
ORGANISM PLAYS IN ITS ECOSYSTEMORGANISM PLAYS IN ITS ECOSYSTEM• ONLY ONLY ONEONE SPECIES CAN SPECIES CAN OCCUPY OCCUPY A A
NICHENICHE AT A TIMEAT A TIME• LEADS TO LEADS TO COMPETITIONCOMPETITION IF MORE THAN IF MORE THAN
ONE SPECIES WANTS ROLEONE SPECIES WANTS ROLE• SIMILARSIMILAR SPECIES CAN SPECIES CAN COEXIST COEXIST AS AS
LONG AS THEY HAVE DIFFERENT LONG AS THEY HAVE DIFFERENT NICHES!NICHES!• EX:EX: p102 in RB – WARBLERS p102 in RB – WARBLERS
HOW CAN I REMEMBER THAT HOW CAN I REMEMBER THAT “NICHE” MEANS ROLE AND “NICHE” MEANS ROLE AND NOTNOT SPACE?SPACE?
• THINK OF A PLAY!• EVERY ROLE NEEDS
TO BE FILLED IN ORDER FOR THE PLAY TO WORK!
• IF MORE THAN TWO FOLKS (SPECIES) WANT A ROLE, THERE IS COMPETITION AND THE BEST WINS!
Food chainFood chain Food webFood web(1 path of energy)(1 path of energy) (all possible energy paths) (all possible energy paths)
What are the relationships in an ecosystem?
B. What are the relationships in an B. What are the relationships in an ecosystem?ecosystem?1. FOOD CHAINS 1. FOOD CHAINS • IllustrateIllustrate NUTRITIONAL RELATIONSHIPS NUTRITIONAL RELATIONSHIPS
between predators and preybetween predators and prey• 1 path of energy1 path of energy• Specific organisms are includedSpecific organisms are included• Let’s take a look!Let’s take a look!
FOOD CHAINSFOOD CHAINS
Feeding Relationships
A. Autotrophs (Producers):
Make own food (grass)B. Heterotrophs (Consumers):
•Herbivores: Eat plants (grasshopper)•Carnivores: Eat animals (snake)•Omnivores: Eat plants and animals (humans)•Scavengers: Eat dead things; life’s clean-up crew! (vultures)•Decomposers: life’s recyclers (bacteria and fungi))
2. SYMBIOTIC RELATIONSHIPS• When organisms live in REALLY close quarters
1. Parasitism: Live off other orgs but don’t kill them (some worms, ticks, fleas)
2. Mutualism: Orgs that both benefit (Clownfish and sea anemone)
3. Commensalism: One org benefits the other - neither harmed or benefitted (Whale and barnacles)
PARASITISM MUTALISM COMMENSALISM
3. FOOD WEBS:•All food chains in an ecosystem are illustrated in a food web•INVOLVES all possible energy paths
Food Webs Food Webs are diagrams that show more are diagrams that show more complex feeding relationshipscomplex feeding relationships
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A simplified food web at a pond
Let’s talk energy! The fuel of life!
• Ask yourself: Where does our ultimate source of energy come from?• The SUN of course!
• Ask yourself: Which orgs can harness sun’s energy and make food?• PLANTS of course!
• Ask yourself: What happens to the plant’s energy when a herbivore eats it?
• • Ask yourself: What happens to the herbivore’s
energy when a carnivore eats it?
• Ask yourself: What happens to the carnivore’s energy when another carnivore eats it?
Decreases
Decreases
Decreases
Every organism uses ENERGY to carry out LIFE processes
If an organism is eaten, it will give less energy to the predatorTHEREFORE, ENERGY DECREASES AS YOU MOVE UP A FOOD CHAIN!
1. What happens to ENERGY in an ecosystem?
Herbivores - Herbivores - CATERPILLARCATERPILLAR
Carnivores - Carnivores - BIRDBIRD
Producers(AutotropProducers(Autotrophs) – OAK TREEhs) – OAK TREE
•WE USE AN ENERGY PYRAMID TO SHOW THIS
•see fig 6-7 and 6-8 on page 107 in your review book!
• As energy is transferred, much of it is lost to the environment
Let’s watch : Let’s watch : http://www.brainpop.com/science/energy/energypyramid
D. RECYCLING NUTRIENTS• DECOMPOSERS extract what little nutrients are left• They return raw materials (nitrogen) back to soil• Other orgs continually recycling CARBON DIOXIDE,
OXYGEN, AND NITROGEN• ENERGY IS NEVER RECYCLED!• involves the processes of RESPIRATION and
PHOTOSYNTHESIS.
Let’s look at pg 108 in RB RECYCLING OF MATERIALS IN ECOSYSTEMS
• Let’s Watch: brain pop carbon CYCLE VIDEO (2:32)