Changes In Ecosystems

Question 1

Explain the term primary succession

Answer 1

Happens when a new patch of land is created or exposed for the first time.

For example, when lava cools and creates new rocks, or when a glacier retreats and exposed rock without any soil.

During primary succession, organisms must start from scratch.

Question 2

How do the early colonisers change abiotic conditions to enable more and more species to thrive?

Answer 2

They die, decompose and release nutrients such as nitrates for production of amino acids and proteins for organisms that follow.
(Notable: increase soil fertility, aeration, barrier against harsh condition and more).

Question 3

Explain the stages of the lithosere

Answer 3

• The development of a community of species on bare rock, created by a cliff fall, the retreat of a glacier, or a volcanic eruption is called a lithosere.
• Initial abiotic conditions are very harsh and unsuitable for most organisms.
• Temperatures are extreme, water availability is severely limited and there is no soil.
• Simple autotrophs such as lichen and algae are the first to colonise the area.
• Conditions improve as dead organic matter and rock fragments gradually accumulate. Mosses colonise anda thin layer of soil starts to biuld up.
• grass and ferns then colonise
• ??????