Transcript Chapter 18 - St. Clair Schools

Chapter 18
Interactions of Living Things
Section 18.1
Living vs. Nonliving
Biosphere
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part of Earth that supports living organisms.
many different environments within biosphere
(ex. grasslands, streams, dessert).
Ecology

study of interactions among organisms and
between organisms and their environment.
Abiotic

nonliving, physical features of the environment.

include water, soil, sunlight, temperature, air
Water
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
50-95% of body
respiration, photosynthesis, digestion all require
water
Soil

type of soil determines what plants/trees will
grow
Sunlight

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light is turned into energy important for life
processes
plants/trees depend on it for photosynthesis
Temperature & Air


climate affects what plants grow and what kinds
of animals can live there
these factors have an effect on organisms and
determine whether or not they are able to live in
a certain environment.
Biotic

living organisms in the environment.


Organism
– single individual from a population.
Population
– all the individuals of one species (group that
reproduces among itself) living in the same
area at the same time
– members of populations compete with each
other for food, water, space, and mates.
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Community
– made up of different groups of populations in
a given area.
– populations of organisms in a community
depend on each other for food and shelter.
Ecosystem
– made up of several communities and the
abiotic factors that affect them.
Section 18.2
Interactions Among Organisms
Population Density


size of a population occupying an area of a
specific size.
more individuals = more dense the population.
Limiting Factors


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any biotic or abiotic factor that restricts
(limits) the number of individuals in a population.
populations cannot continue to grow larger and
larger forever (resources are limited such as
food, water, space, mates).
as population density increases so does
competition.
Carrying Capacity


largest number of individuals an environment can
support and maintain for a long period of time.
if population exceeds this then individuals will
die off or be forced to move.
Predation

Predation
– the feeding of one organism on another.

Predator
– organism that does the killing in predation (biotic
factor).

Prey
– the organism that is killed in predation.
Symbiosis


close relationship between two or more different
species (living together).
types include mutualism,commensalism, and
parasitism.
Mutualism
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
type of symbiotic relationship that benefits (is
good for) both species.
Ex. lichen – made up of an algae (provides food
for fungus) and a fungus (provides protected
living space for algae).
Commensalism


type of symbiotic relationship that benefits one
person but does not harm or help the other.
Ex. orchids growing on trees in rainforest (tree
provides sunlit living space high in canopy for the
orchid).
Parasitism


type of symbiotic relationship that benefits the
parasite and harms the partner (or host).
Ex. tapeworms
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Habitat
– physical location where an organism lives.
Niche
– the role of an organism in the ecosystem.
– what a species eats, how it gets its food, and
how interacts with others are all parts of its
niche.
Section 18.3
Flow of Energy
Food Chain



shows how energy from food passes from one
organism to another.
Energy moves through an ecosystem in the form
of food.
Usually have 3-4 links because available energy
decreases at each link. (only 10% moves to next
level)
Food Chain

Example: Phytoplankton  insects  perch  bass
Food Web
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Series of overlapping food chains.
More complete picture of how energy moves
through a community.
Energy Pyramid

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Shows that energy
decreases at
successive feeding
step (level).
Usually 3-4 levels
because only about
10% of available
energy gets passed to
the next level since
most energy is lost as
heat).
Producer or Consumer?

Producer
– organism that makes its own food.
– Example: plants (photosynthesis)
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Consumer
– organism that gets energy by eating other organisms.
Types of Consumers

Carnivore
– Type of consumer that eats only meat (ex. lion).

Herbivore
– Type of consumer that eats only plants (ex. mouse)
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Omnivore
– Type of consumer that eats both plants and animals (ex.
raccoon).
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Scavenger
– Type of consumer (carnivore) that feeds on the bodies of
dead organisms (ex. vulture)
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Decomposer
– Type of consumer that breaks down waste and dead
organisms (ex. mushrooms)
Animal Defense Strategies

prey use these to protect
themselves from a predator.
Mimicry
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Some animals mimic (or copy) harmful animals to
predators away.
Ex. some flies look like bees, some moths look
like monarch butterflies
Camouflage
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Some organisms match their habitat or
surroundings so predators cannot see them.
Ex. walking stick
False Coloring
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Some organisms have a false eye on back end to
fake out predators so they will bite the tail
allowing the organism to escape death.
Ex. butterfly fish
Warning Coloring
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Some organisms have bright colors to warn
predators that they are poisonous and to stay
away.
Ex. arrow frog
Protective Covering
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Some organisms have spines, hard shell, etc to
protect them and keep away predators.
Ex. turtles, sea urchins, porcupines
Predator Adaptations
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Speed
Sharp teeth or claws
Excellent senses (smell, sight, etc.)
Strength
Agile