Welcome to Ecology

What is Ecology?

Welcome to the Anthropocene…

Inquiry Activity

• In groups of 2-3, you have five minutes to make a list of all of the types of organisms, including plants, humans, animals, insects etc that you have seen in a specific location.

• Rainforest• Tundra!

Inquiry Activity

• Make a diagram that shows how the organisms that you listed interact with each other.

• Who eats who/what?• Where do these organisms live?

Think About It

1. Which organisms on your list provide energy or nutrients to the others? 2. What would you expect to happen if all the plants in your diagram died? EXPLAIN your answer.3. Why is it difficult to make accurate predictions about changes in communities of organisms?

1. Ecology Definitions

3.1: What is ecology?

• Ecology is the scientific study of interactions among organisms and between organisms and their environment

• Etymology (word Root): eco comes from the Greek oikos which means house.

The Biosphere

The biosphere contains the combined portions of the Earth in which all life exists, including land, water and air or atmosphere.

It extends 8 km above the Earth’s surface and as far as 11 km below the surface of the ocean.

Within the Biosphere are levels of organization

1. Ecology Definitions: Feeding relationships

Autotrophs/ Producers/ (Trophic Level 1)

Food energy is most commonly produced from light energy through photosynthesis

Some autotrophs can produce food energy without light, instead using chemicals like hydrogen sulfide. These autotrophs use a process called chemiosynthesis.

Chemotrophs

Some autotrophs can produce food energy without light, instead they use chemicals like hydrogen sulfide. These autotrophs use a process called chemiosynthesis.

Let’s meet some…Deep Sea ChallengerCompare chemosynthesis with photosynthesisGiant Amoeba

Heterotrophs/ Consumers (and decomposers)

Organisms that rely on other organisms for food are called heterotrophs or consumers.

Decomposers can be detrivores or saprotrophs

• detritus 1• detritus 2Decomposers (bacteria and fungi) recycle nutrients (organic matter and other essential elements) in an ecosystem

3. Feeding relationship: Food webs and food chains

Food chains show how food passes from one living

thing to another

All food chains start with a Plant

Plants can make their own food, using sunlight

GRASS

A plant - makes its own food

RABBIT

An animal that eats

plants

FOX

An animal that eats other

animals

The arrows

show the food chain

GRASS

A plant - makes its own food

RABBIT

An animal that eats

plants

FOX

An animal that eats other

animals

The plant is a

‘producer’PRODUCER

GRASS

A plant - makes its own food

RABBIT

An animal that eats

plants

FOX

An animal that eats other

animals

The rabbit is a ‘consumer’ - a herbivore

or plant-eater

PRODUCER

CONSUMER

GRASS

A plant - makes its own food

RABBIT

An animal that eats

plants

FOX

An animal that eats other animals

The fox is also a

‘consumer’ - a predator or meat-

eater

PRODUCER

CONSUMER

CONSUMER

Food chains and food webs work in the same way in the

sea ...

… but the plants and animals look a bit different!

Out in the ocean, there is no grass or

trees

The plants are tiny ALGAE - you need a microscope to see

them

ALGAE

Microscopic plants - make their own food

COPEPOD

A tiny animal that eats plants

FISH

An animal that eats other

animals

This is a food chain in the

ocean

Out in the ocean, there is no grass or

trees

PRODUCER

CONSUMER

CONSUMER

ALGAE

COPEPOD

FISH

The food chain won’t stop there ...

In most habitats, there are several food chains

These are linked together to form a Food Web

Food webs can be quite complicated

Here is one from the ocean around Antarctica …

A simple food chain - whale eats krill

eats algaeCopepods also eat

algae, and are eaten by krill

Fish eat krill and copepods

Squid eat fish and krill

Seals eat squid

and fish

This food web contains 7 types of living things, and 9 food chains

1. Ecology Definitions: Pyramids of energy/ biomass/ numbers

We often use BIOMASS in order to evaluate changes in energy in food chains/webs

Not all energy from food is turned into tissue ‘growth’

• A lot of food energy is used to provide energy for heat, warmth, cellular respiration…

• Some is indigestible, and is ‘lost’ (e.g. cellulose, teeth, claws, skin…)

An example: krill feeding on algae

70 grammes of algae eaten per

day 10 grammes - about 15% - is

indigestible

50 grammes of food are used to provide

energy for swimming and catching more food

This leaves 10 grammes of

food that can be used for

growth

70 grammes

‘in’

= 100%

50 grammes

plus

10 grammes

‘to waste’

= 85% of food eaten

10 grammes to growth

= 15% of food eaten

The same thing happens at every step along the food

chain

Look at the food web from Antarctica ...

A large blue whale will eat 3 tonnes of

krill each day

The amount of growth will be 120 kilogrammes -96%

of the food has ‘gone to waste’

The rate at which animals grow is often related to

their body size

GRASS

RABBIT

FOX

On land, herbivores

and predators are often similar in

size

In the oceans, both the plants and the herbivores are small. There are great size differences

between herbivores and predators

We can understand the size differences more easily if we match each living thing to familiar objects. Here, we magnify each 1000 times

Making each alga cell 1000 times bigger means that it is about the size of a squash ball

Making the krill 1000 times bigger means that it becomes

as long as a small bus

Making the whale 1000 times

bigger means that it is still

huge - it would stretch across

the Isle of Wight

Not all energy from food is turned into tissue ‘growth’

• A lot of food energy is used to provide energy for heat, warmth, cellular respiration…

• Some is indigestible, and is ‘lost’ (e.g. cellulose, teeth, claws, skin…)

• This happens at EACH LINK in the food chain…

The shortest food chain in the Antarctic food web has

two links

LOSS

LOSS

For 100 TONNES of algal growth…

• You get 15 tons of new krill growth• And only 600 kg of new whale growth

The longest food chain in the Antarctic food web has

five links

LOSS

LOSSLOSS

LOSS

LOSS

Now, for 100 tonnes of algal growth

• There is 1 kg of seal growth• Which means that 99.999% of the energy of

the algae eaten by the copepods has been ‘lost’

In the food chain with more links, more producer

growth is lost

A food chain links plants and animals in a habitat

All food chains start with a plant = producer

You have seen that -

Food webs on land and in the ocean are similar

In the ocean, plants and herbivores are small

You have seen that -

Most food in a food chain is turned into energy and lost

Long food chains waste more food than short ones

You have seen that -