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Title: Species, communities and ecosystems
Description: International Baccalaureate Biology SL Topic 4.1 2017 Clear and detailed notes of topic 4.1 from the book and lecture
Description: International Baccalaureate Biology SL Topic 4.1 2017 Clear and detailed notes of topic 4.1 from the book and lecture
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Species, communities & ecosystems
Topic 4
...
1
Biology SL
➢ These organisms are called producers because the food they make is used by other
organisms
○
Ex: algae, trees, grass, cyanobacteria
Heterotrophs
➢ Heterotrophs are organisms that can’t make their own food from inorganic matter
and therefore they get their chemical energy from autotrophs or other
heterotrophs
➢ They’re known as consumers, because they rely on other organisms for food
○
Ex: fish, sheep, insects, zooplankton
➢ Few species are both autotrophs and heterotrophs
➢ Consumers take the energy-rich carbon compounds, protein and lipids synthesized
by other organisms in order to survive
➢ Humans can synthesize vitamin D, because there are precursors in human skin that
absorb UV light waves producing vitamin D
Detritivores
➢ They feed on non-living organic matter called detritus
○
Ex: faeces, dead leaves, carcasses
○
Ex: woodlice, earthworms, dung beetles
➢ Many bottom feeders in rivers, lakes and oceans are detritivores
Saprotrophs
➢ They live on or in non-living organic matter secreting digestive enzymes and
absorbing the products of digestion
➢ They play an important role in the decay of dead organic materials
➢ The fungi and bacteria that are saprotrophs are also called decomposers , because
they break down waste material
Communities
➢ A community is a group of populations living and interacting with each other in an
area
○
Different population of species
➢ “Interacting” can mean:
○
One population feeding on another or being eaten by another
○
One species gets protection from another
2
Species, communities & ecosystems
○
Topic 4
...
Plants can absorb the nitrates turning them back into proteins
➢ They play an important role in the formation of soil
Sustainability of ecosystems
➢ In an ecosystem, all organisms are needed in order to reach sustainability
○
Producers + carbon dioxide ⇒ energy rich sugars ⇒ complex carbohydrates
○
Consumers + producers ⇒ amino acids + sugars
○
Decomposers + dead consumers ⇒ minerals
➢ The scientific term for the “circle of life” is nutrient cycling
➢ Nitrogen is important to organisms, as it’s needed in nucleotides and amino acids
3
Species, communities & ecosystems
○
Topic 4
Title: Species, communities and ecosystems
Description: International Baccalaureate Biology SL Topic 4.1 2017 Clear and detailed notes of topic 4.1 from the book and lecture
Description: International Baccalaureate Biology SL Topic 4.1 2017 Clear and detailed notes of topic 4.1 from the book and lecture