Interactions of Living Things

The Web of Life

Two Parts of the Environment 1. Biotic – the part of the environment

that consists of all of the organisms that live together & interact with one another

2. Abiotic – includes all of the physical factors, such as water, soil, light & temperature, that affect the living organisms

Habitat – environment that provides the things a specific organism needs to live, grow & reproduce

Organisms interact with both the biotic and abiotic parts if the environment.

Niche – how an organism makes its living & interacts with the biotic and abiotic factors in its environment

Ecology – study of how organisms interact with each other and their environment

Organization in the Environment

Level 1 – the individual organism Level 2 – a population of individuals of

the same species Level 3 – different populations form a

community Level 4 – the community & its abiotic

factors form the ecosystem Level 5 – combination of all ecosystems

forms a biosphere

Types of InteractionsTypes of Interactions

Chapter 1: Lessons 2 & 3Chapter 1: Lessons 2 & 3

Interactions with the EnvironmentInteractions with the Environment

Mathematically, populations can grow Mathematically, populations can grow exponentiallyexponentially…so why don’t they?…so why don’t they?

Limiting FactorsLimiting Factors: the environment contains : the environment contains only so much only so much foodfood, water, living space, and , water, living space, and other resources.other resources. Example: if a population becomes too Example: if a population becomes too

large, food becomes a limiting factorlarge, food becomes a limiting factor

Carrying CapacityCarrying Capacity: the largest : the largest populationpopulation that an environment can supportthat an environment can support Example: if there are more organisms Example: if there are more organisms

than an environment can support the than an environment can support the limiting factors cause the population to limiting factors cause the population to get get smallersmaller

Interactions Among OrganismsInteractions Among Organisms

CompetitionCompetition: when 2 or more individuals or : when 2 or more individuals or populations try to use the same populations try to use the same limitedlimited resource. Competition may also occur resource. Competition may also occur within a within a populationpopulation..

Predators & PreyPredators & Prey: : Organism that is eaten is the Organism that is eaten is the preyprey Organism that eats the prey is the Organism that eats the prey is the predatorpredator

Predator AdaptationsPredator Adaptations:: in order to survive in order to survive predators must be able to catch prey, and predators must be able to catch prey, and use a variety of techniques such as: use a variety of techniques such as:

SpeedSpeed CamouflageCamouflage

Prey AdaptationsPrey Adaptations:: in order to survive, prey in order to survive, prey must be able to avoid predation using must be able to avoid predation using techniques such as:techniques such as:

SpeedSpeed Traveling in large groupsTraveling in large groups CamouflageCamouflage poisonouspoisonous

SymbiosisSymbiosis: a close, : a close, long-termlong-term association association between 2 or more between 2 or more speciesspecies

TypesTypes:: Mutualism:Mutualism: both organisms benefit both organisms benefit

Coral & algae – algae produce the food and the coral Coral & algae – algae produce the food and the coral provides a provides a homehome for the algae for the algae

Commensalism:Commensalism: One organism benefits & the One organism benefits & the other is other is unaffectedunaffected

Shark & remora – the remora rides around on the Shark & remora – the remora rides around on the shark feeding off scrapsshark feeding off scraps

Parasitism:Parasitism: one benefits & the other is one benefits & the other is harmedharmed Parasite lives off of the host. The host is Parasite lives off of the host. The host is weakenedweakened

in the process: tapeworm & humanin the process: tapeworm & human

Coevolution:Coevolution: a long-term change that takes a long-term change that takes place in two species because of their close place in two species because of their close interactionsinteractions with one another. with one another. SymbioticSymbiotic relationships may result in relationships may result in

coevolutioncoevolution Flowers & Flowers & pollinatorspollinators show numerous examples & show numerous examples &

evidence of coevolutionevidence of coevolution

QuestionsQuestions What is mutualism?What is mutualism?

Symbiotic relationship in which both organisms benefitSymbiotic relationship in which both organisms benefit Give an example of a parasiteGive an example of a parasite

…….. What is carrying capacity?What is carrying capacity?

the largest population that an environment can supportthe largest population that an environment can support What is a limiting factor?What is a limiting factor?

Any resource that restricts the growth of a population Any resource that restricts the growth of a population of organismsof organisms

EcologicalEcological SuccessionSuccession

Chapter 1 Lesson 4Chapter 1 Lesson 4

• SuccessionSuccession – gradual development of a – gradual development of a communitycommunity over time over time– Example: the regrowth of a forest after a Example: the regrowth of a forest after a wild wild

firefire– Takes place in all communities (not just those Takes place in all communities (not just those

disturbed by things like fire)disturbed by things like fire)– Occurs in predictable Occurs in predictable stagesstages over time over time

• Primary SuccessionPrimary Succession– Occurs when a small community of Occurs when a small community of livingliving

things starts to live in an area not things starts to live in an area not previously containing previously containing organismsorganisms..

– There is no soil, usually just bare There is no soil, usually just bare rockrock

– Over a very Over a very longlong time organisms live and time organisms live and die on the rock and the rock is slowly die on the rock and the rock is slowly transformedtransformed into soil. into soil.

Steps of Steps of PrimaryPrimary Succession Succession1.1. Bare rock is Bare rock is exposedexposed (ex. retreating glacier) (ex. retreating glacier)2.2. Lichens grow on the rock. Lichens grow on the rock. AcidsAcids from the from the

lichens begin breaking down the rock. These lichens begin breaking down the rock. These pieces mix with the dead lichens to form pieces mix with the dead lichens to form soilsoil. . - Lichens are a - Lichens are a pioneer speciespioneer species

3. When the soil is deep enough, 3. When the soil is deep enough, mossesmosses begin to begin to grow and eventually grow and eventually replacereplace the lichens. Other the lichens. Other tiny organisms also live in the soil and when tiny organisms also live in the soil and when they they diedie, add to the soil., add to the soil.

4. The soil layer 4. The soil layer thickensthickens and moss is replaced by and moss is replaced by fernsferns.. Ferns are then replaced by Ferns are then replaced by grasses grasses and and finally by shrubs and small finally by shrubs and small treestrees..

5. After hundreds or 5. After hundreds or thousandsthousands of years the soil of years the soil may be deep enough to support a may be deep enough to support a forestforest..

• Secondary SuccessionSecondary Succession

– Occurs when an existing community is Occurs when an existing community is destroyeddestroyed by a natural disaster such as by a natural disaster such as fire or fire or floodflood

– If the soil is left If the soil is left intact,intact, the original plant the original plant communitycommunity may regrow in a series of may regrow in a series of stagesstages

• Steps of Secondary Steps of Secondary SuccessionSuccession1.1. The The 11stst year after the disturbance many year after the disturbance many

weeds will grow. weeds will grow. CrabgrassCrabgrass is most is most commoncommon

2.2. By the 2By the 2ndnd year, new year, new weedy weedy plants appear, plants appear, their seeds having blown in or been their seeds having blown in or been deposited by deposited by insectsinsects

3.3. In 5-15 years small In 5-15 years small pinepine trees grow trees grow among the weeds. After about among the weeds. After about 100100 years years a forest may growa forest may grow

4.4. As older pines die, they are replaced by As older pines die, they are replaced by hardwoodshardwoods in some climates in some climates

• Succession ends when a Succession ends when a stable stable community has developed.community has developed.– This can be a hardwood forest or a This can be a hardwood forest or a desertdesert

as shown below.as shown below.

Review• What is a difference between Primary &

Secondary succession?– Primary – newly inhabited area– Secondary – an existing community is

destroyed and must redevelop– Other differences???

• How are lichens described by ecologists?– Pioneer species

• How long can it take for a stable community to develop?– Hundreds or thousands of years

Chapter 2 Lesson 1

» Producer˃ Energy comes into most ecosystems in the form of sunlight˃ Organisms that can use the energy of sunlight to make food via photosynthesis

are producers (plants, algae)

» Consumer˃ Consume other organisms as a source of energy˃ Herbivores – eat only plants (cow)˃ Carnivores – eat only animals (coyote)˃ Omnivores – eat plants and animals (bear)˃ Scavenger – carnivore that feeds on the bodies of dead organisms (vulture)

» Decomposer˃ Break down biotic wastes & dead organisms returning raw materials to the

ecosystem (bacteria, fungus)

» Energy moves through an ecosystem when one organisms eats another

» Food Chain˃ Series of events where one organism eats

another obtaining energy˃ Shows only one possible path along which

energy moves

» Food web˃ Consists of many overlapping food chains

» Energy Pyramid˃ Shows the amount of energy that moves from one feeding level to the

next. ˃ Most of the energy is available at the producer level and decreases as

it moves up the pyramid

Chapter 2 Lesson 2Chapter 2 Lesson 2

Cycles of MatterCycles of Matter

The Water CycleThe Water Cycle

The movement among the The movement among the oceansoceans, , atmosphere, land and atmosphere, land and living thingsliving things is is known as the water cycleknown as the water cycle PrecipitationPrecipitation: water moving from the : water moving from the

atmosphere to the land and oceans in atmosphere to the land and oceans in the form of rain, snow, the form of rain, snow, sleetsleet and hail. and hail.

EvaporationEvaporation: sun’s heat causes water to : sun’s heat causes water to change from liquid to change from liquid to vaporvapor..

When the water vapor cools during the When the water vapor cools during the process ofprocess of condensationcondensation it forms a liquid it forms a liquid that can fall back to the that can fall back to the EarthEarth as as precipitation.precipitation.

Ground WaterGround Water: Some : Some precipitation seeps into the precipitation seeps into the ground and may stay ground and may stay underground for hundreds underground for hundreds or or thousandsthousands of years.of years.

TranspirationTranspiration:: All organisms All organisms are made of ~are made of ~70%70% water. water. One function is to regulate One function is to regulate body temperature through body temperature through perspirationperspiration and and evaporation which returns evaporation which returns water to the environment water to the environment in a process known as in a process known as transpirationtranspiration

The Carbon CycleThe Carbon Cycle

The element carbon is essential to The element carbon is essential to living thingsliving things because it is part of all because it is part of all biological molecules (biological molecules (organic organic compoundscompounds))

The movement of The movement of carboncarbon from the from the environment, into living things, and environment, into living things, and back to the back to the environmentenvironment is called the is called the Carbon Cycle.Carbon Cycle.

PhotosynthesisPhotosynthesis: the process by which carbon : the process by which carbon cycles from the environment into living things. cycles from the environment into living things. Plants use COPlants use CO2 2 from the air to make from the air to make sugarssugars.. Most animals get the carbon they need from eating Most animals get the carbon they need from eating

plantsplants

RespirationRespiration:: sugar molecules (C sugar molecules (C66HH1212OO66) are ) are

broken down to release broken down to release energyenergy. CO. CO22 & H & H220 0

are released.are released.

Decomposition:Decomposition: the breakdown of dead the breakdown of dead materials into COmaterials into CO2 2 & H& H220. This returns 0. This returns

carbon to the carbon to the environmentenvironment

CombustionCombustion: the carbon in coal, oil, & : the carbon in coal, oil, & natural gas returns to the natural gas returns to the atmosphereatmosphere when when these fuels are burned.these fuels are burned.

The Nitrogen CycleThe Nitrogen Cycle

Nitrogen cycle is the movement of Nitrogen cycle is the movement of nitrogen from the environment to nitrogen from the environment to living things and living things and backback again. again.

~ 78% of the Earth’s atmosphere is ~ 78% of the Earth’s atmosphere is nitrogen gas, but most nitrogen gas, but most organismsorganisms can’t use the gaseous formcan’t use the gaseous form

Nitrogen-fixing Nitrogen-fixing bacteriabacteria in the soil in the soil are able to change the gas into a are able to change the gas into a form used by plantsform used by plants

Most animals get the nitrogen they Most animals get the nitrogen they need by eating need by eating plantsplants

The final step in the cycle is also The final step in the cycle is also performed by bacteria in the performed by bacteria in the soilsoil. . Bacterial Bacterial decomposersdecomposers return the return the nitrogen to the atmosphere as nitrogen to the atmosphere as nitrogen gas.nitrogen gas.