Download Objective 2 – Life Science – Study Guide

Study Guide for “Organisms and Their Environment” Test
(Ecosystems and Food Webs)
All living things are called organisms. All plants and animals are organisms.
All organisms must live in a certain environment. The
environment where an organism lives must meet its
needs. The specific environment where an organism
lives is its habitat. The right habitat will provide an
organism with the things it needs to survive (shelter,
food, water, etc.). Organisms interact in a habitat.
A group of organisms that can reproduce offspring
that is like themselves is called a species. One
member of a species is called an individual. A group
of organisms of the same species in a certain area at
a certain time is a population. Different populations
of organisms in a community interact with each
other. All the organisms in an environment and how
they interact with each other and the non-living parts
form an ecosystem.
Plants make their own food, so they are called
producers. Plants make their own food using a
process called photosynthesis. Sunlight is captured
by the chlorophyll in the leaves of the plant. Carbon
dioxide enters the plant through tiny holes called
stomata. During photosynthesis, water and carbon
dioxide mix together inside the leaves of the plant
and, with energy from the sun, changes the mixture
into a type of sugar that the plants use for food. Plants
give off oxygen that is made during photosynthesis.
Animals need oxygen to survive. Plants produce
oxygen, so plants help animals survive. Plants and
animals help each other survive in a process called
the carbon dioxide-oxygen cycle. Animals inhale
(breathe in) oxygen, and exhale (breathe out) carbon
dioxide, a process that is called respiration. The
plants take in the carbon dioxide, and use it in
photosynthesis. Then the plants give off oxygen.
Animals are consumers because they eat other organisms. Animals that only eat plants are called
herbivores. Animals that only eat meat are called carnivores. Animals that will eat already dead
animals are called scavengers. Animals that eat both plants and animals are called omnivores.
Animals that feed on dead plants, dead animals, and animal wastes are called decomposers. They
break things down and return nutrients to the soil or water. Animals that hunt are called predators.
Animals hunted by other animals are called prey.
Consumers
Predator
Prey
Energy that organisms need to survive
originally comes from the Sun. The path
of energy from the Sun to a plant to an
animal to another animal is represented
in a food chain. The arrows always
point to the animal that is receiving or
getting the energy. This is called energy
transfer. Less and less of the original
energy from the Sun is transferred to
each organism in the chain.
Animals can be part of many different food
chains. A group of food chains that overlap is
called a food web.