• Author / Uploaded
• pitufo gruñon

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• Depredación
• Red alimentaria
• Herbívoro
• Extinción
• Biodiversidad

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The biosphere

('!) Read and discover. The biosphere is the global ecosystem which contains all other ecosystems. It is like a giant puzzle in which every living thing is an important piece. All organisms are interconnected. If an animal or plant becomes extinct, this will affect other organisms in the ecosystem. One extinction may lead to further extinctions. Preserving biodiversity is our greatest challenge . . Which of your actions help protect the biosphere?

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@why do you think birds fly in groups? Find out why they fly in a V-formation.

@ Explain why sorne living things such as mammoths no longer exist on Earth.

@ Look at the photo of the clownfish and the anemones. why clownfish live among anemones. @Decide if the following sentences are true or false:

• Only organisms of the same species interact. • Fossils are the remains of extinct li)Jing things. • Biodiversity is the variety of life found on Earth . @Read this fragment of Chief Seattle's letter to the US president from 1855. What do you think he was speaking a.bout? This we know: the Earth does not belong to man, man belongs to the Earth. Al/ things are connected [. ..] Whatever he does to the {world], he does to himself

Analyse and organise

'

(!) Organisms of the same species can have different types of relationships; they can cooperate or compete. In your notebook, complete the table choosing from the words in the box. • competition

• parents

• cattle

• cooperative

family groups

'- Stable groups in which the offspring are fed and cared for by the mothers or .•. :. during the first years of life.

hierarchical communities

Ants, termites and ..... live in highly organised societies with each organism specialised in a different role: workers, drones and t he queen.

gregarious species

=1i------·- ---

Sorne animals move, migrate or live in groups to protect themselves against predators. Fish, birds or •..••, form schools, flocks or herds. Two males of the same species compete for a fernale.

Look at the following photos and identify the different relationships from Activity 1.

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, • bees

® @ Read the text and decide if the sentences below are true or false. There are different types of relationships between organisms of different species. Predation occurs when a stronger animal, called a 1nedator, captures, kills and eats an animal of a different species, called prey. Lions (predators) eat zebras (prey).

Parasitism is a relationship that benefits one organism, the 1>arasite, and can harm the other organism. The organism that the parasite depends on is called a host. Mosquitoes feed on the blood of animals and humans and carry various diseases.

Commensalism benefits one organism and does not help or harm the other organism. An example of this is the relationship between · cattle egrets'and cattle. Cattle egrets feed on insects that live on and around cattle.

A mosquito is a host. The relationship between catt!e egrets and cattle is called commensalism. Sorne zebras are prey and others are predators. In both parasitism and predation one organism is harmed.

@@Listen to the recording about mutualism. Complete the missing information in your notebook. • Mutualism is ..... to both organisms. • The clow nf ish keeps the anemone ..... • Bees fly from flower to flower to collect ..... • Bees benefit flowers because ....

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Who's eating who?

ij food chain

always start

Every organism needs food, which provides the en ergy for it to live. The movement of energy through an ecosystem can be represented through food chains and food webs.

with?

A food chain is made up of severa! levels: Producers

Plants and algae are producers. They make their own food through photosynthesis. Consumers

Consumers obtain their food by eating other living things. • Primary consumers, such as rabbits and grasshoppers, eat producers. Herbivores and omnivores are primary consumers. • Secondary consumers, such as foxes and toads, are predators that eat primary consumers. Carnivores and omnivores are secondary consumers. In an ecosystem, the same animal can be both predator and prey. • Tertiary consumers, such as snakes and hawks, eat secondary consumers. Decomposers

Decomposers live on the remains of other living things. Most decomposers are fungi and bacteria.

The Sun

1 l l 1 l

Producer

Prjma ry consumer

Secondary consumer

Food chains show 'who is eati ng who'. Grasses are eaten by grasshoppers, which are eaten by toads, that are finally eaten by snakes.

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Tertiary consumer

What is the main source of energy for plants?

Most living things are part of more than one food chain. There can be many different food chains in an ecosystem and most of these food chains are connected. The connected food chains make up a food web.

Look at Unit 4.

Typical food web in a deciduous forest

(D Decide if the organisms below are producers or primary, secondary or tertiary consumers.

@ Explain the following sentenc;e. Give exa mples.

In an ecosystem, the same animal can be both predator and prey. @Can you think of an animal which is both a primary consumer and a secondary consumer?

@ Draw arrow s to show a food web with the following organisms.

berries bear

deer

grasshopper

bird lizard

mouse snake

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The loss of biodiversity

,,....___ Whyisit important to protect biodiversity?

Extinction occurs when every single member of a species dies and none are left alive. We can say that this species has become 'extinct'. Extinction is often a natural process and has occurred far millions ofyears.

About 65 million years ago a mass extinction occurred causing the loss of nearly 50% of the world's species. This resu lted in the extinction of the

The golden toad was once a common species in Costa Rica. lt

dinosaurs and many other groups of organisms, such as flying reptiles, sorne marine reptiles and ammonites, as well as sorne 'insects and plants. This is not the only mass

is presumed extinct because none have been seen

extinction in the Earth's history.

since 1989.

Biodiversity loss: causes and effects There are many natural causes of extinction, however humans are responsible far most of the recent loss of biodiversity in the world. Thís is a result of severa! destructive practices and their consequences.

hunting and

pollution

releasing pets into the wild

over-exploiting resources

Biodiversity is essential far a healthy planet Earth and has a direct impact on our lives. Once a species is lost it is no longer available to us either as food, enjoyment, or as a resource far medicines and textiles among other things.

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·V

Protecting ·biodiversity Endangered species are those which are in danger of extinction. Wildlife protection groups keep lists of endangered plants and animals in order to protect them. .

National pa rks and biosphere reserves are created to protect wildlife ' and its environment.

The lberian imperial eagle is an endangered species living only in

The lberian lynx is the most endangered cat species in the world. lt exists only in the wild in sorne areas of southern Spain.

restricted areas of Spain. lt is considered the rarest bird of prey in the world.

Doñana National Park is an area of

Monfragüe National Park in

marshes and sand dunes in sout hern Spain.

Cáceres is an outstanding example of Mediterranean forest This

The park has a biodiversity that is uniq ue in Europe. lt is a refuge for sorn e endangered species, such as the lberian imperial eagle and the lberian lynx, as well as numerous migratory birds.

park is considered a bird watchers' paradise because it has both the biggest colony of black vultures and the highest concentration of imperial eagles in the world.

Q (!) What is the difference between an extinct species and ·an endangered species? Give two examples of each.

@ Explain the following sentence. lf biodiversity is at risk, our health and survival are at risk too.

@ Find out which national park is closest to where you live. Search for information about its landscape, location and the plants and animals which live there.

(V Research the different causes of dinosa urs' extinction.

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