Science chapter 12 Flashcards
What is a population?
A group of organisms of the
same species living in a
particular habitat
Every habitat has its own unique physical environment. What factors is it determined by
-light intensity;
– temperature;
– water availability /
humidity;
– oxygen levels; and
– availability of mineral
salts and salinity;
– pH
How is a community formed
The populations of organisms
living and interacting with one
another within a particular
habitat form a community.
How is an ecosystem formed
When different communities of
organisms interact with one
another and with their
environment, an ecosystem is
formed.
What can the environment of an
organism can be classified into? two grps of what
– Abiotic (non-living;
physical) environment; and
– Biotic (living) environment
Ambient light intensity
determines…
the kinds of plants —
and hence, the kinds of animals
— found in a habitat.
Low temperatures slow down…
– slow down the rate of
photosynthesis in plants,
and stunt their growth.
– slow down blood
circulation in animals and
make them sluggish.
Most plants and animals can
survive in temperatures
between
0°C and 45°C.
Adaptation to dry desert environment includes:
-dry feces
specialized desert dwellers, such as the kangaroo rat, have feces five times drier
than that of a laboratory rat
-concentrated urine
desert rats produce urine twice as concentrated as laboratory rats
some lizards, snakes, insects and birds excrete uric acid, rather than liquid urine
-reducing loss of water through exhalation
Some birds have specialized nasal passages that cool the breath before it is exhaled,
condensing water for re-absorption.
Mineral salts are important in the
production of many essential
substances such as
proteins,
vitamins and chlorophyll.
Land plants and aquatic organisms are
pH-sensitive. Most organisms cannot
survive in
extremely acidic or alkaline
environments.
The biotic environment refers to
all the organisms in a habitat.
organisms in biotic environment cannot survive
alone, but each interacts with other organisms
in various ways.
How do organisms in biotic environments keep the balance in the habitat
The organisms form interrelationships
between one another
What is mutualism
Mutualism is a relationship between
two organisms in which both
organisms benefit from each other.
Parasitism is a
relationship
between two organisms in which
one (the parasite) benefits at the
expense of the other (the host).
Predator-prey relationship is
An animal that lives by killing and
eating other animals is called a
predator.
An animal that is killed and eaten
by another animal is called a prey.
What does a food chain show
A food chain shows the transfer of
energy and materials between
organisms through feeding
relationships.
What is a food web made of
A food web is made of inter-linked food chains.
What happens to the total amount of energy in a food chain and
The total amount of energy decreases along
the food chain.
In a balanced ecosystem, the
population sizes of the
predators and prey
remain
relatively unchanged.
The balance of an ecosystem can be upset in
the following ways: (3 ways)
-Introduction of new animals and plants into the
habitat.
-Disease outbreaks, which can kill one kind of
animal or plant.
-Human activities such as deforestation and
over-fishing.
How can you present the energy present in each level of the food chain
The energy present in each level of the food
chain can be shown in a pyramid of energy.
Any change in the relationship
between the organisms can
affect other organisms
directly
or indirectly.
