CHAPTER 4 : ECOSYSTEMS
Notes.
Section 1 Aim: What is Ecosystem?
Why we are learning this:
Ecosystems are important units of the natural world. Humans are part of ecosystems
and depend on ecosystems for food and many products. Without healthy ecosystems,
humans would be in trouble!
Community – a group of various species that live in the same place and interact.
Communities, along with the living and nonliving environment, make up Ecosystem.
Living factors of the ecosystem are called biotic factors. (e.g. animals , bacteria, other
organisms, once-living things such as dead organisms and the waste of organisms)
Nonliving factors of the ecosystem are called abiotic factors.(e.g. water, air, soil,
sunlight, rocks, soil)
Habitat – is the place where an organism lives.
Biodiversity – the variety of the organisms in a given area. Physical factors have a big
influence on biodiversity. When ecosystems have high biodiversity, they are often more
able to resist damage.
Succession – is a process of replacement of one community by another at a single place
over a period of time.
Pioneer species – are the first organisms to appear in a newly made habitat. They
change the habitat in such a way that other species can live in the ecosystem.
Biome – is a large region characterized by a specific kind of climate and certain kinds of
plants and animals. Two key factors that determine climate of biomes are temperature
and precipitations.
Terrestrial biomes: Tropical (tropical rain forests, savannahs, tropical desserts)
Temperate (temperate grasslands, temperate forests, temperate desserts), HighLatitude( taiga, tundra).
Aquatic Ecosystems: Freshwater, Wetlands, Estuary, Marine.