Download Science Unit A

Science Unit A
Chapter 4 Ecology: Lesson 1
An ecosystem is all the living and nonliving parts in an
area.
Living things include plants, animals, fungi, bacteria,
etc.
Nonliving things include soil, sunlight, temperature,
nutrients, and water.
Ecology is the study of the relationship among living
and nonliving parts in an area.
Many different species live together in a tropical rain
forest.
Habitat is the physical place where a species lives.
A niche is the role a species plays in its ecosystem.
All members of a species that live in an area make up
a population.
All the populations living in one area make up a
community.
The different populations of a community interact and
depend on each other.
They also interact and depend on the nonliving parts in
an ecosystem.
Most nutrients in the tropical rain forest are found in
living things
Tropical rain forests:
Have about the same amount of sunlight each day
The temperature stays about the same all year
long
There are no short winter days
Lesson 2
Photosynthesis is the process by which plants use
sunlight to make sugar from carbon dioxide and water.
Plants and other organisms that use light energy to
make sugar from carbon dioxide and water are called
producers.
All organisms, including animals that depend on other
organisms for food are called consumers.
All organisms that are not producers are consumers.
Consumers give off carbon dioxide for the producers
to use.
Three kinds of consumers include:
herbivores – those that eat only plants;
ex. howler monkey
carnivores – those that eat only animals;
ex. jaguars
omnivores – those that eat both plants and
animals; ex. humans
There are also some specialized consumers. They are
vital to life on earth. When a living thing dies in the
rain forest, specialized organisms rapidly break it
down and release its nutrients. Plants reuse these
nutrients for their own growth.
A scavenger is an animal that feeds on the bodies of
dead organisms. Ex. bush dogs, vultures
A decomposer, such as bacteria, fungi, helps break
down and decay dead organisms and the wastes of
living things and change them into simple nutrients
that can be taken up by plants and recycled in
ecosystems.
Without decomposers, soil would not contain enough
nutrients for plants to grow.
Lesson 3
Life on the earth depends on the sun’s energy.
All the energy that consumers get comes from plants,
directly or indirectly.
A food chain shows the path of energy and nutrient
flow in an ecosystem.
The ultimate source of energy is, in nearly all cases
the sun.
An energy pyramid shows the amount of energy
available to organisms at each level in the feeding
order.
At each level, some energy is used to maintain the life
processes of the organisms in that level.
The first level represents the energy trapped by the
trees and all the producers in the rain forest.
This energy is lost as heat.
A food web is a diagram of the feeding relationships
among organisms in a community.
It links together the different food chains in a
community.
Lesson 4
The amount of material that cycle through an
ecosystem stays the same.
The opposite of photosynthesis is respiration.
Respiration is the process by which organisms use
oxygen and sugar to release energy, water, and
carbon dioxide.
Nitrogen Cycle
Nitrogen is a substance that is essential for life. It
is a part of all proteins, materials cells use for
growth and repair.
The amount of Nitrogen stays the same, but it used
over and over.
Nearly 80% of the air you breathe is nitrogen gas.
Most organisms cannot use this form of nitrogen.
They need nitrogen compounds. Nitrogen compounds
can be formed by lightning combine with other
substances or some kinds of bacteria can also change
nitrogen gas into nitrogen compounds.
Bacteria and other decomposers break down organic
matter and in the process release forms of nitrogen
that plants can use. In this way, nitrogen is recycled
in the environment.
Water Cycle
Water cycles through living and nonliving parts of an
ecosystem.