unit 2. ecosystems

ECOSYSTEMS

What is an ecosystem?

Group of living and non-living things that live in the same area. They all interact.

Living things in an ecosystem:

They are organised in:

Species: group of organisms that can reproduce with each other and produce fertile offspring.

Population: all the individuals that belong to the same species.

Community: group of different populations that live together.

How do they interact?

Depending on how living things get their food they can be classified in:

Producers: they are the plants. They use soil and energy to perform the photosynthesis and produce food. Other living things use plants as food.

How do they interact?

Decomposers: bacteria and fungi. They feed off the remains of dead animals and plants. Then, they return this nutrients to the soil for the plants.

How do they interact? Composers: animals and organisms that feed on

other living things. Primary consumers: they eat producers, so they

are herbivores (rabbits eat grass).

Secondary consumers: they eat other consumers, so they are carnivores (eagles eat rabbits).

Tertiary consumers: eat both producers and consumers, so they are omnivores (birds eat fruits and worms).

How do they interact?

Food chains and food webs

Food chain: living things eat each other passing the energy from one to another.

Food chains and food webs

Food webs: most living things are part of several food chains. When we connect them, we have a food web.

Food chains and food webs

Balance of living things: if one population changes, it can affect other populations. As a result, it modifies the ecological balance. When a big change affects the balance of living things, it can lead to the extinction of species.

Terrestrial ecosystems

Cold deserts: Antarctica and Greenland. They have:

Freezing temperatures Little precipitation Land is covered with snow and ice Very little vegetation Animals have thick layer of fat

Terrestrial ecosystems

Terrestrial ecosystems

Taiga: in Russian means dense evergreen forest. Covers the very North of Europe, Asia and North America. It has:

Very cold temperatures (snow in Winter) Long and reainy days in Summer Many evergreen trees

Terrestrial ecosystems

Terrestrial ecosystems

Temperate forests: are located in canada, eastern United States, Europe and China. They have:

Cold temperatures in Winter and mild in Summer

Moderate rain Most trees are deciduous Wide variety of animals that migrate during

cold winters

Terrestrial ecosystems

Terrestrial ecosystems

Warm deserts: Sahara and Atacama deserts. They have:

High temperatures during day and cool at night

Scarce precipitation Very little vegetation Animals can survive with little amounts of

water.

Terrestrial ecosystems

Terrestrial ecosystems

Terrestrial ecosystems Savannahs: cover half the surface of Africa.

You can also find them in Australia, South America and India. They have:

High temperatures all year There is a dry season (almost no rain) and a

wet season (lots of rain) Land is covered mostly in grass, few trees and

shrubs Wide variety of animals

Terrestrial ecosystems

Terrestrial ecosystems

Rainforests and jungles: Amazon and Congo are the largest in the world. They have:

High temperatures Rains all year long Abundant vegetation

Terrestrial ecosystems

Aquatic ecosystems

There are two type of aquatic ecosystems:

Marine: the oceans and the seas

Freshwater: lakes, ponds, rivers and streams

Aquatic ecosystems

Marine ecosystems: in it we can find producers, consumers and decomposers.

Producers: phytoplankton (algae). They perform photosynthesis.

Consumers: fish, marine mammals, starfish, coral and zooplankton.

Decomposers: fungi, bacteria and other microorganisms.

Aquatic ecosystems

φύτον (phyto n, "planta") y πλαγκτος ("plánktos", "vagabundo" o "el que va dando tumbos")

‘Zoo’ (animal) y πλαγκτός [p la g któ s ], ‘errantes’

Aquatic ecosystems