UNDERSTANDING LIFE SYSTEMSINTERACTIONS IN THE

ENVIRONMENT

ECOSYSTEMS

Grade 7 Curriculum Focus

FUNDAMENTAL CONCEPTS/BIG IDEAS:

Ecosystems are made up of biotic (living) and abiotic (non-living) elements, which depend on each other to survive.

Ecosystems are in a constant state of change. The changes may be caused by nature or by human intervention.

Human activities have the potential to alter the environment. Humans must be aware of these impacts and try to control them

OVERALL EXPECTATIONS:

1. assess the impacts of human activities and technologies on the environment, and evaluate ways of controlling these impacts;

2. investigate interactions within the environment, and identify factors that affect the balance between different components of an ecosystem;

3. demonstrate an understanding of interactions between and among biotic and abiotic elements in the environment.

UNDERSTANDING BASIC CONCEPTS:

By the end of Grade 7, students will:

3.1 demonstrate an understanding of an ecosystem (e.g., a log, a pond, a forest) as a system of interactions between living organisms and their environment

3.2 identify biotic and abiotic elements in an ecosystem, and describe the interactions between them (e.g., between hours of sunlight and the growth of plants in a pond; between a termite colony and a decaying log; between the soil, plants, and animals in a forest)

3.3 describe the roles and interactions of producers, consumers, and decomposers within an ecosystem

Natural ecosystems:

Man made ecosystems:

TYPES OF ECOSYSTEM

Tundra Forest Desert Grassland Crop field

GardenOcean Estuary/ Sea Coast

Pond / Lake

River / Spring

MARINE FRESH WATER NATURAL MAN MADE

AQUATIC ECOSYSTEM

TERRESTRIAL ECOSYSTEM

Producers

Consumers Decomposers / Converters

What is interdependence?

What is an ecosystem?

An ecosystem is a habitat in which living (biotic – plants, animals and microorganisms) and non-living (abiotic) things interact with one another and their surroundings. An ecosystem’s living members make up a community. Many different species of a organisms form an ecosystem, but their population can vary, depending on their roles.

An ecosystem can be any size. A log in a forest is an ecosystem.

From inside our bodies to under the ocean floor, microbiomes —communities of bacteria and other one-celled organisms — thrive everywhere in nature. Emerging at least 3.8 billion years ago, they molded our planet and created its oxygen-rich atmosphere. Without them, life on Earth could not exist.Yet we know surprisingly little about the inner workings of nature's smallest and most complex ecosystems.

Humans, like all other animals, are home to hundreds of different kinds of bacteria and other micro organisms. We are a walking ecosystem!

WHAT DO YOU NOTICE IN COMMON?

Types of Ecosystems

Five Needs of All Living Things(Different from Characteristics of all Living Things!)

Living things meet their basic needs by interactingwith living and non-living things.

WHAT LIVING THINGS NEED WHAT IT DOES WHERE IT IS FOUND

OXYGEN Helps your body get energy from food Air

WATER Helps your body to function: plants need water to make food

Reservoirs, freshwater lakes and rivers

FOOD Provides the vitamins, minerals and other things your body needs to grow and repair itself; food it converted to energy

Environment

ENERGY Keeps your body functioning so you can breathe, stay warm and be active

Food, water and air

SUITABLE HABITAT Provides all the things you need to survive; provides protection

Houses, forests, ground, tree, water…

What is Photosynthesis

How a producers uses the Sun’s Energy Sunlight is an important abiotic element in most ecosystems Sunlight enables photosynthesis to take place Photosynthesis is a chemical reaction that uses sunlight to produce food

for plants. Carbon Dioxide from the air combines with water from the roots to make

food called glucose (a type of sugar) and oxygen The food is stored in the plant, and the oxygen is released back into the air. Animals, including humans, use the oxygen that plants produce during

photosynthesis. Photosynthesis occurs in the leaves of a plant. It uses light energy from the

Sun.

Illustration of PhotosynthesisSunlight shines of the leaf and brings heat and light energy, causing a chemical reaction

A sugar, called Glucose is produced.

Oxygen is released from the leaf

Water and nutrients from the soil come to the leaf through the plant stem or trunk

Carbon dioxide from the air enters the leaf

Seven Characteristics of all

Living Things

Feeding

Breathing

Movement

Excretion

Growth

Sensitivity

Reproduction

What is the relationship?

1. Humans cannot live more than three or four days without water: __________________

2. Tiny wild berries are a major food source for the lumbering black bear: _____________

3. Wind is one of the sources responsible for soil erosion: _____________________

4. The beaver builds its shelter, a partially submerged lodge, out of logs harvested from trees in its own habitat: _______________________

5. Snakes and other reptiles use the warmth of he sun to raise their body temperatures after a cool night: ___________________

6. For a typical meal, the, “cleaner fish,” cleans the gills and teeth of other bigger fish, which in turn, become cleaner: ___________________

BIOSPHERE: The ecosystem that encompasses the entire Earth, including the land surface,

water and atmosphere

BIOME: A large area of Earth defined by similar plants, animals, weather patterns and

landforms, such as a tropical rainforest.

INTERACTIVE ECOSYSTEMS – nesting circles

show how one ecosystems exists within a larger ecosystem

BIOSPHERE

BIOME

RIVER BANK

THE TRANSFER OF ENERGY IN ECOSYSTEMSPRODUCERS AND CONSUMERS

All animals are consumers. Consumers are living things which cannot make their own food. They must eat, or consume other living things in order to survive. They are described by what they consume

TYPE OF CONSUMER FOOD EATEN EXAMPLES

HERBIVORE Plants Deer, Canada Geese

CARNIVOR Meat Hawk, Polar Bear

OMNIVORE Meat and Plants Racoon, Pig

SCAVENGER Feed off animals that are already dead Vultures, Crows

DETRITVORES Feed of waste products from other living things and dead insects

Earthworm

DECOMPOSERS Living things that break down waste products and dead plants and animals into smaller pieces.

Mushrooms, bacteria

THE TRANSFER OF ENERGY IN ECOSYSTEMSPRODUCERS AND CONSUMERS

A Producer uses sunlight to make food and this food provides the producer with the energy it needs to live, grow and reproduce. Some of the producer’s energy is transferred to a consumer once the producer is eaten.

In an ecosystem, energy is transferred from one organism to another.

PREDATOR / PREY

Predator – an animal that hunts another animal for food

Prey – an animal that is hunted by another animal.

THE TRANSFER OF ENERGY IN ECOSYSTEMS

Energy is transferred from the Sun through food chains to all living things Energy is always flowing through ecosystems Energy transfer always begins with the Sun and Producers It then moves from different consumers through the Food Chain

Here is what happens to the energy from the Sun

As energy is transferred from one organism to another, some energy is lost. Only a small amount of an organism’s energy is transferred in a food chain; therefore, an ecosystem needs more of the eaten than the eaters. The higher up an organism is in the food chain, the smaller its population.

THE TRANSFER OF ENERGY IN ECOSYSTEMS

Here is what happens to the energy from the Sun1. Some is used for living2. Some is given off as heat3. Some is stored.

The tree stores energy from the Sun and uses some of that energy to grow and to heal itself.

Most of the energy the insect gets from the leaf is used by the insect to move, grow and stay alive. Very little energy is stored by the insect, so in turn he passes on very little insect to a predator that eats him (i.e. the bird), so the bird must eat MANY insects to get enough energy for it to survive

THE TRANSFER OF ENERGY IN ECOSYSTEMS

Here is what happens to the energy from the Sun

As energy is transferred from one organism to another, some energy is lost. Only a small amount of an organism’s energy is transferred in a food chain

therefore, an ecosystem needs more of the eaten than the eaters. The higher up an organism is in the food chain, the smaller its population

Only stored energy can be passed onto the next consumer. Only about 10% of the energy taken in by a consumer can be passed on to the next consumer in the food chain.

Each living thing uses a large percentage of the energy it receives. This means that there is a much smaller amount of energy for living things at

the next level of the food chain. For living things that are still higher in the food chain, there is even LESS

energy in the food they consume

Scientists have different names for different types of consumers.

There is less and less energy available in each step of the food chain

PRODUCER

PRIMARY CONSUMERS Herbivores

Or Omnivores

SECONDARY CONSUMERS Omnivores

Or Carnivores

TERTIARY CONSUMERS Omnivores Or

Carnivores

HOW MATTER CYCLES THROUGH AN ECOSYSTEMPlants are eaten by consumers. The abiotic elements are passed on to the consumer. The abiotic elements are stored or returned to the soil as waste products.

Consumers die and are broken down by decomposers. The organic matter is consumed by decomposers. The decomposers break the organic matter down and return the useful things it contains to the soil.

Plants take abiotic elements from the soil. Through the process of photosynthesis, these abiotic elements become food and are stored in the roots or fruits of the plants. Some of these elements include carbon, nitrogen and iron.

Minerals and other nutrients needed by plants go around in a never-ending circle. This circular pattern is called a cycle.