2. 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
Habitat – environment that provides the
things a specific organism needs to live,
grow & reproduce
3. 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
4. Organization in the
Level 1 – the individual organism
Level 2 – a population of individuals of
the same species
Level 3 – different populations form a
Level 4 – the community & its abiotic
factors form the ecosystem
Level 5 – combination of all ecosystems
forms a biosphere
6. Interactions with the EnvironmentInteractions with the Environment
Mathematically, populations can growMathematically, 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 muchonly so much foodfood, water, living space, and, water, living space, and
other resources.other resources.
Example: if a population becomes tooExample: if a population becomes too
large, food becomes a limiting factorlarge, food becomes a limiting factor
7. Carrying CapacityCarrying Capacity: the largest: the largest populationpopulation
that an environment can supportthat an environment can support
Example: if there are more organismsExample: if there are more organisms
than an environment can support thethan an environment can support the
limiting factors cause the population tolimiting factors cause the population to
8. Interactions Among OrganismsInteractions Among Organisms
CompetitionCompetition: when 2 or more individuals or: when 2 or more individuals or
populations try to use the samepopulations try to use the same limitedlimited
resource. Competition may also occurresource. Competition may also occur
within awithin a populationpopulation..
Predators & PreyPredators & Prey::
Organism that is eaten is theOrganism that is eaten is the preyprey
Organism that eats the prey is theOrganism that eats the prey is the predatorpredator
9. Predator AdaptationsPredator Adaptations:: in order to survivein order to survive
predators must be able to catch prey, andpredators must be able to catch prey, and
use a variety of techniques such as:use a variety of techniques such as:
Prey AdaptationsPrey Adaptations:: in order to survive, preyin order to survive, prey
must be able to avoid predation usingmust be able to avoid predation using
techniques such as:techniques such as:
Traveling in large groupsTraveling in large groups
10. SymbiosisSymbiosis: a close,: a close, long-termlong-term associationassociation
between 2 or morebetween 2 or more speciesspecies
Mutualism:Mutualism: both organisms benefitboth organisms benefit
Coral & algae – algae produce the food and the coralCoral & algae – algae produce the food and the coral
provides aprovides a homehome for the algaefor the algae
Commensalism:Commensalism: One organism benefits & theOne organism benefits & the
other isother is unaffectedunaffected
Shark & remora – the remora rides around on theShark & remora – the remora rides around on the
shark feeding off scrapsshark feeding off scraps
Parasitism:Parasitism: one benefits & the other isone benefits & the other is harmedharmed
Parasite lives off of the host. The host isParasite lives off of the host. The host is weakenedweakened
in the process: tapeworm & humanin the process: tapeworm & human
11. Coevolution:Coevolution: a long-term change that takesa long-term change that takes
place in two species because of their closeplace in two species because of their close
interactionsinteractions with one another.with one another.
SymbioticSymbiotic relationships may result inrelationships may result in
Flowers &Flowers & pollinatorspollinators show numerous examples &show numerous examples &
evidence of coevolutionevidence of coevolution
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 populationAny resource that restricts the growth of a population
of organismsof organisms
14. • SuccessionSuccession – gradual development of a– gradual development of a
communitycommunity over timeover time
– Example: the regrowth of a forest after aExample: the regrowth of a forest after a wildwild
– Takes place in all communities (not just thoseTakes place in all communities (not just those
disturbed by things like fire)disturbed by things like fire)
– Occurs in predictableOccurs in predictable stagesstages over timeover time
15. • Primary SuccessionPrimary Succession
– Occurs when a small community ofOccurs when a small community of livingliving
things starts to live in an area notthings starts to live in an area not
previously containingpreviously containing organismsorganisms..
– There is no soil, usually just bareThere is no soil, usually just bare rockrock
– Over a veryOver a very longlong time organisms live andtime organisms live and
die on the rock and the rock is slowlydie on the rock and the rock is slowly
transformedtransformed into soil.into soil.
16. Steps ofSteps of PrimaryPrimary SuccessionSuccession
1.1. Bare rock isBare rock is exposedexposed (ex. retreating glacier)(ex. retreating glacier)
2.2. Lichens grow on the rock.Lichens grow on the rock. AcidsAcids from thefrom the
lichens begin breaking down the rock. Theselichens begin breaking down the rock. These
pieces mix with the dead lichens to formpieces 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 tobegin to
grow and eventuallygrow and eventually replacereplace the lichens. Otherthe lichens. Other
tiny organisms also live in the soil and whentiny organisms also live in the soil and when
theythey diedie, add to the soil., add to the soil.
4. The soil layer4. The soil layer thickensthickens and moss is replaced byand moss is replaced by
fernsferns.. Ferns are then replaced byFerns are then replaced by grassesgrasses andand
finally by shrubs and smallfinally by shrubs and small treestrees..
5. After hundreds or5. After hundreds or thousandsthousands of years the soilof years the soil
may be deep enough to support amay be deep enough to support a forestforest..
18. • Secondary SuccessionSecondary Succession
– Occurs when an existing community isOccurs when an existing community is
destroyeddestroyed by a natural disaster such asby a natural disaster such as
fire orfire or floodflood
– If the soil is leftIf the soil is left intact,intact, the original plantthe original plant
communitycommunity may regrow in a series ofmay regrow in a series of
19. • Steps of SecondarySteps of Secondary SuccessionSuccession
1.1. TheThe 11stst
year after the disturbance manyyear after the disturbance many
weeds will grow.weeds will grow. CrabgrassCrabgrass is mostis most
2.2. By the 2By the 2ndnd
year, newyear, new weedyweedy plants appear,plants appear,
their seeds having blown in or beentheir seeds having blown in or been
deposited bydeposited by insectsinsects
3.3. In 5-15 years smallIn 5-15 years small pinepine trees growtrees grow
among the weeds. After aboutamong the weeds. After about 100100 yearsyears
a forest may growa forest may grow
4.4. As older pines die, they are replaced byAs older pines die, they are replaced by
hardwoodshardwoods in some climatesin some climates
20. • Succession ends when aSuccession ends when a stablestable
community has developed.community has developed.
– This can be a hardwood forest or aThis can be a hardwood forest or a desertdesert
as shown below.as shown below.
• What is a difference between Primary &
– 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
23. » 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)
˃ 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)
˃ Break down biotic wastes & dead organisms returning raw materials to the
ecosystem (bacteria, fungus)
24. » 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
28. The Water CycleThe Water Cycle
The movement among theThe movement among the oceansoceans,,
atmosphere, land andatmosphere, land and living thingsliving things isis
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 theatmosphere to the land and oceans in the
form of rain, snow,form of rain, snow, sleetsleet and hail.and hail.
29. EvaporationEvaporation: sun’s heat causes water to: sun’s heat causes water to
change from liquid tochange from liquid to vaporvapor..
When the water vapor cools during the process ofWhen the water vapor cools during the process of
condensationcondensation it forms a liquid that can fall back toit forms a liquid that can fall back to
thethe EarthEarth as precipitation.as precipitation.
30. Ground WaterGround Water: Some: Some
precipitation seeps into theprecipitation seeps into the
ground and may stayground and may stay
underground for hundreds orunderground for hundreds or
thousandsthousands of years.of years.
TranspirationTranspiration:: All organismsAll organisms
are made of ~are made of ~70%70% water. Onewater. One
function is to regulate bodyfunction is to regulate body
temperature throughtemperature through
perspirationperspiration and evaporationand evaporation
which returns water to thewhich returns water to the
environment in a processenvironment in a process
known as transpirationknown as transpiration
32. The Carbon CycleThe Carbon Cycle
The element carbon is essential toThe element carbon is essential to livingliving
thingsthings because it is part of all biologicalbecause it is part of all biological
molecules (molecules (organic compoundsorganic compounds))
The movement ofThe movement of carboncarbon from thefrom the
environment, into living things, and back toenvironment, into living things, and back to
thethe environmentenvironment is called the Carbonis called the Carbon
33. 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 CO22 from the air to makefrom the air to make sugarssugars..
Most animals get the carbon they need from eatingMost animals get the carbon they need from eating
RespirationRespiration:: sugar molecules (Csugar molecules (C66HH1212OO66) are) are
broken down to releasebroken down to release energyenergy. CO. CO22 & H& H220 are0 are
34. Decomposition:Decomposition: the breakdown of deadthe breakdown of dead
materials into COmaterials into CO22 & H& H220. This returns0. This returns
carbon to thecarbon to the environmentenvironment
CombustionCombustion: the carbon in coal, oil, &: the carbon in coal, oil, &
natural gas returns to thenatural gas returns to the atmosphereatmosphere whenwhen
these fuels are burned.these fuels are burned.
36. The Nitrogen CycleThe Nitrogen Cycle
Nitrogen cycle is the movement ofNitrogen cycle is the movement of
nitrogen from the environment tonitrogen from the environment to
living things andliving things and backback again.again.
~ 78% of the Earth’s atmosphere is~ 78% of the Earth’s atmosphere is
nitrogen gas, but mostnitrogen gas, but most organismsorganisms
can’t use the gaseous formcan’t use the gaseous form
Nitrogen-fixingNitrogen-fixing bacteriabacteria in the soilin the soil
are able to change the gas into aare able to change the gas into a
form used by plantsform used by plants
37. Most animals get the nitrogen theyMost animals get the nitrogen they
need by eatingneed by eating plantsplants
The final step in the cycle is alsoThe final step in the cycle is also
performed by bacteria in theperformed by bacteria in the soilsoil..
BacterialBacterial decomposersdecomposers return thereturn the
nitrogen to the atmosphere asnitrogen to the atmosphere as
nitrogen gas.nitrogen gas.