Biology Objective 3
Demonstrate an understanding of the
interdependence of organisms and the
environment.
Biomes
Identified by biotic and abiotic factors
• Biotic – what kinds of plants and animals live in it.
• Abiotic – Nonliving characteristics such as soil
type, rainfall amounts, and average temperature
cycles.
A scientist has hypothesized that the
existence of life on Mars is likely because
Mars’s atmosphere is 95% carbon dioxide.
36 Which question is valid in testing this hypothesis?
F Do most other scientists agree with the hypothesis?
G Could abiotic processes account for the carbon dioxide?
H What is the percent of argon compared to carbon dioxide
in the Martian atmosphere?
J Have the scientist’s other predictions about Mars been
validated?
36 Which question is valid in
testing this hypothesis?
F Do most other scientists
agree with the hypothesis?
G Could abiotic processes
account for the carbon
dioxide?
H What is the percent of
argon compared to carbon
dioxide in the Martian
atmosphere?
J Have the scientist’s other
predictions about Mars
been validated?
When testing an hypothesis,
there should be only one
variable changed at a time. If
this is not possible, then all
possible reasons for an
outcome need to be
considered. In this case,
carbon dioxide can be
produced by chemical
reactions other than cellular
respiration, which is a biotic
process. That is why answer
G is the best answer.
What are they referring to?
• Biosphere – The entire
area of the planet that
supports life.
• Biome – An area defined
by specific abiotic and
biotic factors.
• Community – The groups
of living things in an area
and how they relate.
Ecology – The study of the
relationships among living things
• Symbiosis is a close relationship between
two living things.
• When both are helped it is called mutualism
• When one is helped and there is no effect on
the other it is called commensulism
• When one is helped and the other is harmed
it is called parasitism
Mutualism . . .
Sharks are cleaned by
a little fish known
as a Remora. The
shark never eats
them since they
clean bacteria off of
the shark. Since
both species are
helped, this is
mutualism.
Commensulism . . .
Orchids live high
in tree-tops on
the branches of
large trees. They
do not harm the
tree, but they are
helped by being
raised up into the
sunshine and
receiving water.
35 Clown fish are small reef fish that seek protection
from predators by sheltering themselves among the
stinging tentacles of sea anemones. Clown fish are
very territorial and can potentially scare off
predators of sea anemones. This relationship is an
example of -A neutralism This is not a type of symbiosis Incorrect
Since both are helped, it
B mutualism
is of mutual benefit or
C parasitism Neither is harmed so this is incorrect
D commensalism
Means only one is being helped and the relationship
has no effect on the other – also incorrect
What is helped?
Both the ants and the tree.
This is the definition of:
All energy on the earth comes
from the sun.
• Prey are the animals
that are eaten as a food
source for the . . .
• Predator This is the
hunter animal. The
population of the
predator must be less
than the prey or they
do not have enough
food.
Population (100s)
Predator and Prey
Time (months)
Prey
Predator
To increase the predator
population you could do what?
24 Which of the following is most likely
to cause increases in a predator
population?
F Fewer prey Reduces available food – Nope!
G A reduction in competition
Less predators, they
H More parasites would
Less
and prey,
bepredators
sick or dying!
J A period of drought they’d be gone looking for
water!
Population (100s)
Carrying Capacity
Time (months)
P rey
P redat or
• This is the maximum number of a specific
population that an area can support with enough
food and living requirements. It is shown by a
line on population graphs for a specific species.
2 Because of this animal’s adaptations, it
would be most successful at —
F competing with
birds
G making its own
food
H hiding from
predators
J running very
rapidly
And the answer is?
• H hiding from predators.
• Its not a plant, so it can’t
make food.
• It has no wings, so it can
not compete with birds.
• Although it has long
legs, it doesn’t seem
balanced for running.
Man’s Effects on the Environment
• Ozone O3 is a protective layer at the top of the
atmosphere.
• However, when it occurs near the ground, it is
very harmful to all living things, it is SMOG
Man’s Effects on the Environment
• More than 90% of
fresh water is locked
in ice at the polar
caps and in glaciers.
• Much of the fresh
water is polluted by
land run-off, dumping
of wastes and excess
heat directly into
lakes, oceans and
rivers.
Man’s Effects on the Environment
Global warming, also
called the Greenhouse
Effect is caused by
excess burning of fossil
fuels and destruction of
our oxygen producing
protista in the oceans,
and deforestation on
land. Less plants
means less oxygen and
more CO2.
54 Which of these activities can help
conserve natural resources?
What is the phrase for ecology?
F Recycling cardboard
boxes
G Washing small loads of
laundry
H Driving large cars
J Building wooden fences
Yes! Recycle!
Not saving water!
Wasting fuel!
Cutting down trees
that give oxygen and
clean air!
Evolution:
The process of change over time.
• There are natural variations in all populations.
• As climate changes occur, and as pressures in
terms of food, space, shelter and predation
occur, some variations allow a species to
survive.
• The members who survive, reproduce causing
the change to become a characteristic of the
species.
Speciation:
Separation into new species.
• Geographic isolation
can cause two
different natural
variations to become
prominent causing 2
separate species.
• Reproductive isolation
can have the same
effect.
What is extinction and what causes it?
• A population is extinct when the last of that species is
dead.
• Example: There are no more dinosaurs.
• What happened? Their habitat was destroyed. When
they no longer have what they need to live, they die.
Fossils
• These are imprints or
remains of living things.
• In undisturbed layers of
sedimentary rock, the
deeper it is, the older it
is.
• Give us information
about extinct species.
Homologous vs. Analogous Structures
• Homologous means they • Analogous means they
have the same origin, but
have the same function but
may be different now.
come from different
origins.
• Example, the upper arm
bones in dogs, cows, cats • Example, bird wings and
and monkeys.
wings of bats.