Organisms, the Environment, and Human Impact An Overview

Think, Ink, Pair Share What is an Ecosystem? Draw or write a description of what you think of when you hear the term ecosystem. Explain your drawing or read your description to your partner. Then listen to their description. (Person with the longest hair goes first).

What is an ecosystem? An ecosystem refers to all the living organisms (biotic factors) that live in a particular area as well as all of the non-living, physical components (abiotic factors) with which the organisms interact, such as air, soil, water, and sunlight. Different organisms are adapted to live in different ecosystems. Different ecosystems can be close together. Some organisms belong to several ecosystems.

What is an environment? Everything that affects an animal makes up its environment - where it lives, the weather and all the living things it comes into contact with. Every living thing, including people, has an effect upon the environment.

Think, Ink, Pair, Share In order to survive, living things need…

Homes and Habitats The place where an animal lives is called its habitat. An animal lives where it can find food, water, shelter and a mate.

Living things (biotic): All living things (organisms) need food (nourishment) to live. Living things in an ecosystem depend on each other for food in order to obtain energy.

Think, Ink, Pair, Share All living things need energy to survive. Energy cannot be made by living things so they have to get it from somewhere. The original source of energy for all living things is _________ because …

Producers Plants are living organisms. They need energy to survive. But plants do not eat other plants or animals to obtain energy. Plants are called producers because they make their can transform radiant energy from the sun into chemical energy through photosynthesis in order to get the energy they need to survive.

Consumers “Consume” means “eat”. Animals are consumers because they “eat” (consume) food provided by plants or other animals in order to obtain energy needed for survival.

Some animals, like the kingfisher, eat only other animals. Carnivores Some animals, like the kingfisher, eat only other animals.

They survive only on plants. Herbivores Some animals do not eat other animals. They survive only on plants.

Omnivores Some animals, like us, eat both plants and animals.

A predator eats other animals. Cats eat fish. So do bears!

Predator The cat is a predator because it eats other animals. The bear is a predator because it eats other animals. People are predators too!

Prey Any animal which is hunted and killed by another animal for food is prey. Predator Prey

Match the predator to its prey.

Predators and Prey Some animals are predators, some are prey - some are both. The predator eats the prey and the prey gets eaten by the predator.

A food chain shows the direction that energy flows in an ecosystem. The fly is eaten by the thrush. SO the fly passes a portion of its energy on to the thrush.

Food Chains A food chain shows what is eaten. A food chain shows the direction that energy flows in an ecosystem. The lettuce is eaten by the rabbit. A portion of the chemical energy stored in the lettuce is passed on to the rabbit.

Food chains always start with a producer. A portion of stored chemical energy from the lettuce is passed on to the slug when the slug eats the lettuce. A portion of stored chemical energy from the slug is passed on to the bird when the slug is eaten by the bird. *Which organism consumed the least amount of energy- the slug or the bird? Justify your answer.

Think, Ink, Pair, Share The arrows of a food chain tell you …

Reminders for Interpreting Food Chains - A food chain shows which animals eat other animals or plants but is really showing the direction that energy flows through the ecosystem Producers (such as plants) don’t eat things so they will never have an arrow pointing to them (unless it comes from the sun) A food chain starts with what gets eaten and the arrows point towards the organism that receives the energy once it consumes another living organism. Food chains only go in one direction. Organisms at the end of the chain consume less energy in one feeding than organisms at the beginning of the chain.

Think, Ink, Pair, Share Some animals are identified as being on top of the food chain because …

The top of the food chain. Some animals are said to be at the top of the food chain. This is because they are not hunted and eaten by other animals. No other animal hunts the lion. The lion is at the top of the food chain.

Think, Ink, Pair, Share What is the difference between a food chain and a food web? Draw a food chain and then draw a food web. (you may use words or pictures to represent the different organisms)

Food Webs In the wild, animals may eat more than one thing, so they belong to more than one food chain. To get the food they need, small herbivores may eat lots of different plants, and carnivores may eat many different animals. Energy Pyramids can be constructed to show which organisms in the food web are located in different tropic levels (levels indicate the amount of energy available)

Food Webs- show multiple pathways for an organism to obtain energy. owl fox rabbits mice grass seeds berries

Energy Pyramid

Think, Pair, Share What is one way that a change in the environment could effect living things?

Breaking the Chain Organisms living in a habitat depend on each other. If one part of a food chain dies out or is greatly reduced, the consumers have to find alternative food, move away, or starve. This then affects more consumers in the same way.

Short and Long Term Changes in the Environment Affect Organisms- loss of habitat (woodlands cut down, rivers drying up, hedgerows removed). chemicals or pollution poison the animals. hunting (for sport, their fur, tusks or meat) All members of the species are less successful in reproducing and thus are less likely to pass on genetic information (possibly becoming endangered or extinct). Or some individuals will become more successful and lead to changes in traits for future generations of the species.

Caring for the Environment It is in our own best interests to look after the world we live in. If a habitat is lost or damaged, it has an effect on everything else, even if we do not see or understand it right away. Remember - once something becomes extinct, it’s gone forever!