Download Ecology Study/Resource Guide

Science
•• Use appropriate tools and instruments to observe and measure objects
and phenomena
•• Develop and use models to represent systems or phenomena, make predictions
and inferences, test hypotheses, and support explanations
•• Organize scientific information in tables, charts, and graphs, as appropriate
•• Formulate scientific claims and arguments based on evidence
•• Understand how science knowledge grows and changes
Unit 1: Ecology
In this unit, you will study the interdependence of life on Earth. You will demonstrate
the development and use of dichotomous keys to classify organisms based on defining
characteristics. You will describe major biomes and communities in which organisms
live and learn to recognize the effects of changes in environmental conditions. You will
begin to learn about relationships between organisms and examine the dependence of
organisms on their environments.
KEY TERMS
An organism is any life form. All animals, plants, and single-celled life forms are
organisms. Organisms are also known as living things. Living things can breathe, move,
grow, reproduce, and—owing to this—require energy to continue living. (S7L1)
Nonliving things include dead organisms as well as objects such as minerals that
never were alive. Dead organisms are still considered to be organic material, while
other nonliving things are often inorganic. Nonliving things do not respond to stimuli,
they cannot adapt to their environment, and they cannot evolve. Generally, if a thing
does not contain cells, it would be nonliving. Nonliving things also do not show any of
the characteristics of living things, such as breathing and growing. (S7L1)
The environment is all the living and nonliving things that surround an organism. All
the factors that influence the survival, development, and evolution of an organism are
also part of an environment. A change in the environment can affect the survival of the
individuals or species that live in that environment. (S7L4e)
When people refer to an ecosystem, they are referring to the community of living
and nonliving things that make up a system in an environment. The key idea is that
an ecosystem is a system located within an environment. A pond with producers,
consumers, and decomposers in it that is located on a mountain is an example of
an ecosystem. In this model, the mountain could be considered the environment.
Environmental changes in an ecosystem can affect the survival of individual animals
and species within an ecosystem. (S7L4c, e)
A general type of an ecosystem is known as a biome. A biome is defined by local
climate patterns and types of plants that can be found in the biome. A savanna in
Africa is warm, is dry, and has a lot of grasslands. A stream on your way to school is a
freshwater biome. The water is warm, flows, and contains algae as a producer. (S7L4e)
Terrestrial biomes are those biomes that are on land. Rain forests, savannas, deserts,
tundras, and mountains are examples of terrestrial biomes. (S7L4e)
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Georgia Milestones Grade 7 EOG Study/Resource Guide for Students and Parents
Copyright © 2015 by Georgia Department of Education. All rights reserved.
Science
Aquatic communities are biomes found in water. Scientists divide aquatic
communities into two regions: freshwater and marine. Freshwater aquatic communities
are areas that have water with low salt levels, such as ponds, lakes, streams, rivers,
and wetlands. Marine aquatic communities have higher salt levels and include oceans,
coral reefs, and estuaries. (S7L4d)
The populations and interactions of two or more species in a geographical area are
known as a community. In a community, separate populations impact each other’s
behavior and survival. (S7L4d)
Interdependency describes how species rely on each other to meet their needs.
Consumers are dependent on producers as a source of energy. In some cases, being
dependent can be mutually beneficial. Some birds eat berries whole. They are
dependent on the berry plant as a source of energy. The berry plant benefits from this
relationship because the birds will release some of the berry seeds into other areas, so
the berry plant as a species can reproduce. (S7L4d)
When organisms or species interact and one of those organisms or species has some
aspect of its ability to survive impacted, they are said to be competitive. Ants and
beetles compete for the same types of food. Sparrows will compete for living space with
martins by stealing the martins’ nests. (S7L4d)
You classify things when you organize them into groups based on characteristics they
share. Scientists classify things so they can study ways those things are similar or
different. A classification system can be used to identify and study that species. (S7L1b)
Living things are classified using a six-kingdom system. The six kingdoms are animals,
plants, fungi, protists, archaebacteria, and eubacteria. The earliest method to classify
living things used a two-kingdom system of animals and plants. As scientists started
studying organisms with microscopes, they realized that some organisms did not fit
their classification as either an animal or a plant. This gave rise to the additional four
kingdoms. (S7L1a)
A dichotomous key is a tool that helps identify organisms based on making a choice
between two characteristics. People develop dichotomous keys by starting at a
characteristic that two organisms have in common, such as flying. Bats, wasps, and
robins fly. The next step would be to find some common characteristic that at least
two of those flying animals share. This step is repeated until the dichotomous key
leads to clearly identifying a species by separating it from the others based on traits.
Dichotomous keys are often revised as they are developed. (S7L1a)
Important Tip
The way scientists have classified organisms has changed over the years. In the
earliest systems, organisms were either a plant or an animal. Scientists have learned to
base their classification on similar body structures rather than functions. For example,
dolphins and sharks both live in the water, swim, and are gray. However, dolphins are
mammals and have lungs, and sharks are fish and have gills. Scientists classify based
on similar genetic backgrounds that have led to having similar body structures. When
you work on classifying organisms, keep in mind that you should look for similar traits
and that new information may require you to modify your classification system. (S7L1a)
Georgia Milestones Grade 7 EOG Study/Resource Guide for Students and Parents
Copyright © 2015 by Georgia Department of Education. All rights reserved.
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Science
Sample Items 1–2
Item 1
A science class develops its own dichotomous key for identifying animals with hooves.
Dichotomous Key for Orders of Mammals
Step 1
Step 2
Step 3
Step 4
Step 5
1a
Has long trunk
Proboscidea
1b
Does not have long trunk
Go to Step 2
2a
Has limbs with fingers and toes
Primate
2b
Does not have limbs with fingers and toes
Go to Step 3
3a
Has limbs with sharp claws, not hooves
Go to Step 4
3b
Has limbs with hooves, not claws or nails
Go to Step 5
4a
Has sharp teeth and eats meat
Carnivore
4b
Eats insects
Insectivore
5a
Has limbs with even-toed hooves
Artiodactyla
5b
Has limbs with odd-toed hooves
Perissodactyla
Zebra
Zebra hoof
Using the dichotomous key, to which order does the zebra belong?
A.
B.
C.
D.
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Artiodactyla
Carnivore
Perissodactyla
Proboscidea
Georgia Milestones Grade 7 EOG Study/Resource Guide for Students and Parents
Copyright © 2015 by Georgia Department of Education. All rights reserved.
Science
Item 2
Four different biomes are described in a table.
Type of Organisms
Humidity Level
Biome 1
Trees and lichen
Relatively dry
Biome 2
Grasses and shrubs
Very dry
Biome 3
Evergreen trees
Relatively humid
Biome 4
Mangrove trees
Very humid
Which biome represents the type of ecosystem of a desert?
A.
B.
C.
D.
Biome 1
Biome 2
Biome 3
Biome 4
Georgia Milestones Grade 7 EOG Study/Resource Guide for Students and Parents
Copyright © 2015 by Georgia Department of Education. All rights reserved.
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