Ecology 6.6

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

Today's lesson

A bit of a review

Discuss 6.6 - Ecological succession

Which of the following is usually true about secondary consumers in an ecosystem?

1. They eat only plants
2. They are eaten by primary consumers
3. They are fewer in number than are primary consumers
4. They contain the greatest total biomass in the system

Which of the following best explains why there are seldom more than five trophic levels in a food chain?

1. Most carnivores function at more than one trophic level
2. Top carnivores are too few in number to hunt effectively
3. The ecosystem contains too much biomass
4. Energy is lost from each trophic level

Ecological succession

Pioneer community

Lichen

• is a composite organism that arises from algae living among filaments of multiple fungi species in a mutualistic relationship
• 6-8% of the earth is covered by lichen
• 20,000 different species
• reproduce asexually

Moss

• small, non-vascular flowerless plants that  dense green clumps or mats, often in damp or shady locations
• individual plants are usually composed of simple leaves that are generally only one cell thick
• do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores

Steps in succession

1. Pioneer species come in 
2. Through their existence they change the abiotic factors (add nutrients to ground, create shade, block wind etc)
3. This makes the environment suitable for other species to come in
4. These new species can outcompete the previous species making them dissapear from the system
5. This creates a follow up of species over time, because the population keep on changing the environment

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Climax community

Plant and animal species are constant

They are no longer replaced by other species

A high amount of biodiversity

Complex food web