CHAPTER 24

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CHAPTER 24INTERACTIONS OF LIFE(Page 684)
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The Biosphere

• the part of the Earth which supports life.
• - high in the air.
• - underground.
• - under oceans.
• it would compare to the thickness of the skin on
  an apple.
• - about five miles thick.

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Ecology

• - the study of the relationship between organisms
  and their environment.

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Abiotic factors

• the non-living parts of the environment.
• ex. Soil, water, light, temperature.

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Biotic factors - the living organisms. - they
need the abiotic factors.
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___________________________________The
environment is organized into levels. (p.
686).

• Population
• - organisms of the same species living
  together.

Ex. All the people in Tokyo. All the
rabbits in Burleigh County.
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2) Community

• different populations living together.
• Ex. All the rabbits, mice, ants, and elm trees
  in Bismarck.

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3) Ecosystem

• organisms and the non-living environment.
• Can be as small as a potted plant or your
  backyard.
• As large as an ocean.

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4) Biosphere

• - made up of all the ecosystems.

Read pages 688 - 692.
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Population Characteristics

• Population Density -the number of organisms per
  unit of space.

Ex. People per square kilometer
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Birthrate

• the number of offspring produced in a certain
  time.
• Ex. Babies born in Bismarck over the last year.

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Deathrate

• the number of organisms that die over a certain
  time.
• If the birthrate is greater than the deathrate,
  the population rises.

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Population is also effected by

• Immigration
• when new organisms enter an area.
• Emigration
• - when members of a population leave an area.

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A census counts the population.

• The United States Census Bureau does a census
  every ten years.

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ASSIGNMENTWORKSHEET COMMUNITIES
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Biotic potential - the number of individuals
that could be produced under the best conditions.

• Ex. A sea turtle lays 100 eggs and all survive
  to adulthood.

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A population will never reach its biotic
potential - because of limiting factors.

• Ex. predators, disease, harsh weather, etc.

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Ex. A sea turtle lays 1,800 in its life time. -
1,400 dont even hatch - predators, injury to
eggs, temp. - most hatchlings are prey. - only
three survive to produce.
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• Carrying Capacity
• the largest number of individuals the environment
  can support.
• - enough food? - enough space?

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Human Populations

• The worlds population is about 6. 2 billion in
  2005

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2 billion in 1930 1 billion in 1850 500 million
in 1650
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The human population is doubling at a faster rate
- increasing the fastest in the last 100 years.

1. Improvements in medicine and sanitation.
2. More food production.
3. Life expectancy has increased.

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The birthrate has stayed the same, but the
deathrate has dropped a lot.

• The lights of cities at night

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Currently, the worlds population will double
every 35 years.

• what is the Earths carrying capacity?
• Can we produce enough food?

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ASSIGNMENTWORKSHEET POPULATIONS
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--------------------------------------------------
--------Habitat

• the place where a population lives.
• Every ecosystem has many habitats.

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• Ex. Forest
• - birds in the canopy.
• - badgers underground.
• - deer on the forest floor.

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Many populations can live in the same habitat.

• the habitat of a species may be inside or on
  another species.
• Ex. bacteria in your digestive system.

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Each population has a function (or role) for its
habitat.

• called a niche.
• ex. A fox is a predator.
• A plant is a producer.

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If two organisms occupy the same niche they will
compete for food, territory, mates, etc.
-the one that adapts the best will survive. -
smartest? strongest? fastest?
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RELATIONSHIPS BETWEEN POPULATIONS

• 1. Predator - Prey Relationship
• - most common within a community

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When the predator population is high, the prey
population will be low

• the predators will die of starvation and disease
  (or emigrate).
• Then the prey population rises.
• This cycle is continuous

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2. Parasitism
Ex. wood tick on a dog.

• - one organism benefits while the other is harmed.

(parasite)
(host)
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A parasite will not usually kill the host.

• - because that would also kill the parasite.

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ASSIGNMENT Section Self Check Questions. P. 687
1/2/4 P. 718 2/3
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3) Commensalism

• a relationship between two organisms where one
  benefits and the other is not affected.
• Ex. clownfish and
• a sea anemone.

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4) Mutualism

• where both organisms benefit.
• Ex. remora and shark

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----------------------------------------Every
population needs energy.

• starts with plants.
• called producers because they can make their own
  food.

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Consumers

• - organisms that eat other organisms.

• Herbivores
• eat only plants
• Ex. cows, deer, horses.

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Carnivores- eat other animals.Ex. polar bear,
lion
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Omnivores- eats both plants and animals.Ex.
bear, raccoon
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Scavengers- eat dead animals.Ex. vulture, hyena
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Energy is transferred thru the community by a
food chain.

• - must start with a plant.

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Put these organisms into a food chain.
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There are many food chains in an environment.
- they connect to form a food web. (p. 728).
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Energy Pyramid
Top carnivore
carnivore
herbivore
Plants
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Why is it shaped in a pyramid?
Top carnivore
carnivore
herbivore
Plants
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Top carnivore tiger, killer whale, eagle

• Only 10 of the energy is passed on to the next
  level.

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ASSIGNMENTWORKSHEET FOOD CHAINS
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Decomposers

• organisms that break down wastes and dead
  organisms.
• Ex. Bacteria, mushrooms

They return nutrients (oxygen, carbon, nitrogen)
to the ecosystem.
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These nutrients are then used by plants. - and
the cycle starts over again,
Ex. Nitrogen Cycle
COPY DRAWING ON THE BOARD
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ASSIGNMENTP. 706 Checking Concepts 11 -
19P. 708 Multiple Choice 1 - 10