Biosphere

SG Biology

How it works?

The Biosphere Investigating an ecosystem

Sampling and other measurement techniques applied to the investigation of an ecosystem.

How it works Components of an ecosystem,

energy flow,

population growth,

controlling factors.

Control and management Intervention in the natural balance of an ecosystem;

using understanding to manage ecosystems.

Identification

Think of a species (plant or animal)

Write down a description of your

species on a piece of card.

Exchange the card with another

member of the class.

Could they identify the species you

have described?

Identification keys

Identification keys help us to identify plants and animals. Have a look at the samples of keys available in class.

The two types of key you could use are: Numerical key

Branched key

Complete the worksheet on identification keys

Food Chains

Watch the Scientific Eye video

making notes on food chains, and

factors affecting populations.

Food Chains and Food

Webs

Environment and Feeding

Definitions Herbivore:

An animal that eats grass and other green plants in a food chain;

Carnivore: A flesh-eating animal.

Prey: An animal hunted or caught for food

Predator: An organism that lives by preying on other organisms.

Definitions Primary consumer:

An animal that eats grass and other green plants in a food chain; an herbivore.

Secondary consumer: An animal that feeds on smaller plant-eating animals in a food chain.

tertiary consumer: An animal that feeds on secondary consumers in a food chain.

Population: All the organisms of the same species living in the same place at the same time.

Food Chains Food chains are one way of showing how

organisms interact. For example:

Grass Rabbit Fox

The arrows represent the flow of energy

(food) between organisms, it points from

the eaten to the eater.

All food chains start with plants, they use sunlight during photosynthesis to build up food (energy) stores, these are then passed on to animals.

Important terms: Plants are producers because they produce their own food

Animals are consumers because they eat food to obtain energy.

There are 3 types of consumer Herbivores eat plants

Carnivores eat other animals

Omnivores eat plants and animals

Organisms that breakdown dead plants and animals are called decomposers, e.g. fungi, bacteria and worms

Producer primary secondary tertiary consumer consumer consumer

PLANTS HERBIVORE CARNIVORE TOP CARNIVORE

Food Webs

When several food chains in a

habitat are studied, some organisms

appear in more than one.

This is because most animals eat

more than one type of food.

If food chains in a habitat are linked,

they form a FOOD WEB.

Food web for a single tree

Which are the primary and secondary

consumers in this photograph?

Competing for the same

niche

Biosphere

How it works?

Populations

Adaptations

Factors affecting population size

Populations

A population is a group of

individuals of the same species living

in a particular habitat at the same

time.

The number of individuals present in

the population will depend on how

they can interact with two types of

factor.

Populations

Living factors – food, disease,

predation, mates, effects of

humans, and competition

Non-living factors – water, oxygen,

carbon dioxide, temperature and

light

Competition for Resources Plants and animals compete for resources.

Plants often compete with each other for space, and for nutrients and water from the soil.

Animals often compete with each other for space, water and food.

Competition for Resources

There are two types of competition: Intra-specific – competition between individuals of the same species

Red deer stags fight to

mate with the females

Boobies compete for

nesting space

Plants compete for space, light,

water and nutrients.

Competition for Resources

Inter-specific – competition between individuals of different species.

Garden birds compete for

food in winter

Factors affecting population size

A population is a group of individuals of the same species living in a particular habitat.

Births and immigration increase the size of a population.

Deaths and emigration decrease the size of a population.

Factors affecting population size

The size of a population, may also be affected by:

The total amount of food and water available, if food supply is low, then individuals will compete for them.

Oxygen shortage can limit numbers in a population that lives in water.

Poisons can build up in the environment and limit population growth.

Factors affecting population size

List continued from previous page:

Predation will limit the prey population.

Disease can spread quickly through

large populations.

Climate – drought, flood and storms all

affect population numbers.

Lack of shelter

Competition for light

Population Graphs

For one species in good conditions

1

2

3

4

time

Number of

individuals

For one population in good condition

1. Slow increase as only a few individuals.

2. Sharp increase, good conditions for growth

3. Some factors start to slow down increase (e.g. lack of food).

4. Stable population (birth rate = death rate)

Predator-prey relationships

Animals that kill and eat other animals are called predators. The animals that they eat are called prey.

Predators are usually bigger and fewer in number than their prey.

List five things that make a good predator:

List five ways prey have adapted escape from predators:

The graph shows the relationship

between a predator and its prey.

List what is happening in each of

the stages 1 – 5 on the predator

prey graph.

1. The prey has plenty of food. It breeds and increases in number.

2. The increase in prey means that there is more food for the predator. So the predator breeds and increases in number.

3. There are now lots of predators so more prey will be eaten. The number of prey goes down.

Predator prey graph 4. There are now less prey for the predator

to feed on. Food will be scarce and

many predators starve.

5. With fewer predators, more prey survive

to breed. The prey numbers increase

The cycle continues…

Adaptation

The Biosphere

How it works?

Learning Outcomes

To explain the terms ecosystem,

habitat and community.

To understand that physical factors

affect animals living in an ecosystem

To be able to explain how animals

are adapted for survival in arctic

and desert conditions.

What is an Ecosystem?

The Environment An ecosystem is an environment where living organisms can survive.

The environment is made up of lots of different ecosystems, such as seashore, a wood or a river.

Each ecosystem is made up Habitats and Communities

Habitat - This is the place where the organisms live. It has the conditions that they need to survive.

Community – all the living organisms that live in the habitat.

Physical Factors Each ecosystem has a set of environmental factors.

Availability of water

Temperature - Few living organisms can grow outside the range of 0oC to 40oC.

amount of Light - photosynthesis in plants, animals need light for visibility.

Availability of carbon dioxide and oxygen

These factors vary according to the time of day and the time of year.

Adaptations

Living things adapt to their

environment.

Watch the video clip, and then try

to fill in the table explaining how the

creature is adapted to it’s

environment.

Adaptations in different

animals

Look at the animals on the

worksheet, for each one try to give

where it lives and an example of

how it is adapted for survival in its

environment.

Pupil Activity

Surviving in different environments.

Read all information carefully

Answer questions 1 - 9

Camel

designed for desert conditions

Big flat feet stop it sinking into the sand.

Short hair underneath the camel

lets heat escape.

Coarse wool on top of its body protects the camel from the sun.

A camel’s hump is a fat store. It can break down fat to release water.

A camel can drink large amounts of water. Its mouth is tough so that it can eat thorny plants like cacti.

Adaptations to water loss

a cactus in the desert Leaves reduced to spines – to reduce water loss

through stoma

Swollen stem

stores water

Wide spread root

systems to increase

surface area for absorption.

Camel – designed for desert conditions

Big flat feet stop it sinking into the sand.

Short hair underneath the camel

lets heat escape.

Coarse wool on top of its body protects the camel from the sun.

A camel’s hump is a fat store. It can break down fat to release water.

A camel can drink large amounts of water. Its mouth is tough so that it can eat thorny plants like cacti.

Adaptations to water loss - a cactus in the desert

Leaves reduced to spines – to reduce water

loss through stoma

Swollen stem

stores water

Wide spread root

systems to increase

surface area for absorption.

Class activity To draw labelled diagrams of a cactus, a camel and a polar bear which explain how they are adapted to their environment.

Use one side of your exercise book for each diagram, and labels.

Use the handouts to help you with the labels.

Commendations will be awarded for exceptional work!

Pupil Activity - extension

Environmental factors affecting life

Read all the information supplied on

the sheet carefully.

Answer questions 1 – 11 in full

sentences.