unit 2. ecosystems
TRANSCRIPT
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