Transcript a 09 Population limit factrs carr cap ppt

http://www.mark-ju.net/wildlife/images/monkey03.jpg
http://www.dimijianimages.com/Aggression-defense-page4/vultures.jpg
Ecosystem Interactions
&
Factors that affect populations
http://www.epa.gov/region5/superfund/ecology/images/fishcartoon.gif
http://www.uark.edu/depts/agripub/Publications/Agnews/mosquito.jpg
What is a population?
• A group of members of the same
species that live in the same area.
• The size of any population is constantly
changing.
• WHY?
Limiting factors - an environmental factor that
prevents an increase in the number of
organisms in a population or prevents them from
moving into new habitats
Limiting Factors that affect
populations in ecosystems:
2 types:
1) Abiotic
- a) resources available
- b) climate
- c) natural and human disturbances
2) Biotic
- a) competition among organisms
- b) predation
- c) cooperation and symbiosis
- d) presence of disease
ABIOTIC:
WHAT IS A RESOURCE?
Anything needed by an organism for life
Examples:
Nutrients, water, sunlight/energy, space
_____________________________
ABIOTIC:
What are examples
of climate?
• temperature, humidity, atmospheric
pressure, wind, rainfall
These in turn can cause/contribute
to some natural disturbances like:
storms, droughts, fires
ABIOTIC:
What are examples of human
disturbances?
• logging
• development and construction
BIOTIC:
What is competition?
• interaction between 2 or more organisms
competing for the same resource in a given
habitat
• Can occur between members of same species
- Example: male mountain goats compete to determine
who will mate and produce offspring
• Members of different species may compete for
the same resources
- Example: raccoons and ravens might both try and feed
on eggs from the same nest of a common bird
BIOTIC:
Competition
• For similar species to live together in the
same area, they must have slightly different
niches.
WHAT CAN ORGANISMS COMPETE FOR?
- All the abiotic factors!
- Mates!
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources. FOOD
http://www.knology.net/~sgoswald/Eating.jpg
http://www.harcourtschool.com/glossary/science/images/gr3/community3.jpg
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: shelter
http://www.dpiw.tas.gov.au/inter.nsf/Images/LBUN-5K538R/$File/fox_adultandcub.jpg
http://www.gdccc.org/Records/EOY2004/NSEOY.htm
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: space/territory
http://www.elise.com/weblog/photos/prairie-dogs.jpg
Prairie dogs - 5 to 35 per acre
Mountain lion- 1 male per 50-300 sq. mi
http://www.rilanationalpark.org/gr.phtml?dir=../../pictures/in_text&img=/65_1180.jpg
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: LIGHT
http://vilenski.org/science/safari/cellstructure/chloroplasts.html
http://www.csjbacau.ro/gallery/images/Beech%20Tree%20Forest%20in%20Slanic%20Moldova.jpg
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources
mates
http://www.wasatchcomputers.net/gallery/elk_fight.jpg
http://www.biocrawler.com/w/images/thumb/3/34/200px-Peacock_courting_peahen.jpg
BIOTIC:
What is predation?
• when one organism hunts and kills another
organism for food
Prey animals are well adapted to avoid
being eaten. Some examples include:
- Physical attributes: speed, mimicry
- Physical defences: camouflage, quills (porcupine)
- Chemical defences: odour (skunk), ink spray
(octopus), etc…
Mimic Octopus (2:59 min): http://www.youtube.com/watch?v=H8oQBYw6xxc
PREDATION
Organisms in an ecosystem that capture
and eat other organisms to supply their
energy needs
http://personal.ecu.edu/wuenschk/rabbit-wolf.gif
http://www.aphis.usda.gov/lpa/pubs/images/wspred_6.jpg
BIOTIC:
What is cooperation?
- between SAME kind of organisms
- live together and help each other
What is symbiosis?
• Between 2 DIFFERENT species
• live in/on or near a member of another
species
COOPERATION
Same species live together in groups
EX: herds, packs, colonies, families, etc
Share food &
childcare responsibilities
Groom each other
Take care of sick
http://www.kenyatravelideas.com/african-elephants.html
http://www.sphoto.com/medium/meercats37.jpg
http://people.uleth.ca/~d.rendall/groom4.jpg
COOPERATION
Same species live together in groups
EX: herds, packs, colonies, families, etc
Hunt in packs
Provide protection
http://www.knology.net/~sgoswald/Eating.jpg
http://rosswarner.com/zebras1.jpg
3 KINDS of SYMBIOSIS
1)______________________
MUTUALISM
Both organisms benefit
COMMENSALISM
2)______________________
One organism benefits;
Other is neither harmed nor helped
PARASITISM
3)_____________________
One organism benefits;
Other is harmed in some way
Bed bugs (2:10 min): http://www.youtube.com/watch?v=WfKCcSPCOQo
1) MUTUALISM
“Good for me - Good for you”
Birds eat parasites living
on the hides of giraffes and
rhinos while enjoying
protection from predators.
Groomed animals lose their
pests.
http://www.imbt.org/science.htm
http://www.hugheshome.net/jon/africa02/images/rhino_bird_JPG.jpg
1) MUTUALISM
“Good for me - Good for you”
Insects transfer pollen
between plants as they
gather nectar for food.
http://www.providence.edu/bio/faculty/adams/LECTUREProvCollegeMutualism.html
http://www.yksd.com/DistanceEdCourses/YKSDbiology/lessons/SecondQuarterLessons/Chapter5/5-5/images/3-way-mutualism.jpg
MUTUALISM cont’d
“Good for me - Good for you”
Clown fish gets protection from enemies
by hiding out in poisonous sea anemones
Sea anemone gets
scraps of leftover
food dropped
by fish
http://www.zahnersatz.com/english/library/symbiosis.jpg
2) COMMENSALISM
“Good for me - Doesn’t bother you”
http://www.geology.wmich.edu/gillespie/g322/Chapters/C16shark.gif
Pilot fish receive scraps of food dropped by shark;
Shark is neither harmed nor helped
COMMENSALISM cont’d
“Good for me - Doesn’t bother you”
http://www.abyssal.com/meeks/images/hermit_crab.jpg
Hermit crabs make homes in shells abandoned by snails;
Snail is not harmed by crab
3) PARASITISM
“Good for me - Hurts you”
http://www.geology.wmich.edu/gillespie/g322/Chapters/C16parasitism.whale.gif
Barnacles are crustaceans that attach to the surface of whales
and feed on their skin and fluids; Whale is harmed
PARASITISM cont’d
“Good for me - Hurts you”
http://www.dogbreedinfo.com/guineafowltickphotos.htm
Tick feeds on dog’s blood;
Dog has discomfort, can get diseases/infection from bite
PARASITISM cont’d
“Good for me - Hurts you”
Tapeworms absorb
food by living inside
host intestine;
host is harmed
http://www.biology.ucok.edu/AnimalBiology/Platyhelminthes/tapeworms.jpg
INTERDEPENDENCE
All living and non-living things in an
ecosystem are interconnected and changing
even one thing impacts the whole ecosystem.
When one tugs at a single thing in nature,
he finds it attached to the rest of the world.
~John Muir, naturalist, Sierra Club founder
• Have you ever wondered why we
don’t see millions of mice running
around when we look out the window
if they reproduce so quickly?
• The environment can only support a
maximum number of individuals because
of limited resources
Characteristics of a Population:
• As a population grows, each individual gets a
smaller share of the resources in the area.
• If resources are scarce, some organisms will
starve and populations will decrease.
• The organisms become stressed. Some die,
others aren’t able to reproduce.
• This may lead to fewer births and more
deaths. Eventually,
the number of births = number of deaths
• The population is in EQUILIBRIUM
REMEMBER: EVERYTHING IS CONNECTED !
BIOLOGY; MIller and Levine; Prentice Hall; 2006
•A decrease in the prey population means some predators will starve.
•Fewer predators mean prey population will increase.
•Increase in prey means more food for predators.
•Predator population will increase until there is not enough food . . .
and the cycle repeats itself.
•Rabbit/Wolf simulation: http://www.shodor.org/interactivate/activities/RabbitsAndWolves/
Carrying Capacity
• Carrying Capacity is the
maximum number of
individuals an ecosystem
can support without
reducing its ability to support
future generations of the
same species
• The population overshoots
the carrying capacity before
it is reached
• If a population exceeds
carrying capacity for a long
time, it usually harms its
environment.
• For an ecosystem to be sustainable, none
of the populations in the community can
exceed its carrying capacity by very much
or for very long.
• GOAL OF SUSTAINABILITY:
meet the needs of the present generation
without affecting the ability of future
generations to meet their needs
Human Population Growth
Questions:
1) What does the following graph suggest
about our population growth rate in the
future? Discuss each line.
Questions:
2) Brainstorm reasons why the human
populations seems to be growing
exponentially, even after analyzing the
previous graph.
(You may use ideas from the Bill Nye
video on Populations.)
Questions:
3) a. Finish sketching in the following curve based on the
general graph showing a population reaching carrying
capacity.
b. If this were a graph of the Earth’s population, estimate
the following:
i) overshoot population
ii) carrying capacity population