F215:03:04 Succession Flashcards Preview

F215:03 Ecosystems and sustainbility > F215:03:04 Succession > Flashcards

Flashcards in F215:03:04 Succession Deck (23):

What is succession?

a directional change of a community of organisms over a time


Give a recent example of succession

The island of Surtsey in Iceland was created by a volcano eruption in the 1960's.
Began as bare ground but is now home to a community of plants


What is primary succession?

The transformation from bare ground to a community of plants.


Describe the pioneering community

When algae and linchens begin to live on bare rock


How is soil formed from bare rock?

Rock erosion and the build up of dead and rotting organisms producing enough soil for plants like mosses and ferns to grow, which succeed the algae and linchens


What is a climax community?

The stage at which larger plants have succeeded smaller pnes and the final, stable community is reached


What does succeed mean?

to replace


Does succession always start from bare ground?

No, secondary succession takes place of previously colonised, but disturbed or damaged habitats.


Give an example of a good environemnt that displays all the stages of succession in the same place at the same time and show why

Sand Dunes
As the sea deposits sand on the beach, so the sand just above the high water mark is the start of the succession process, and sand much further away hosts its climax community.


Outline the stages of succession

1. Pioneer plants colonise bare ground/sand that can tolerate the harsh conditions
2. Plants colonise that stabalise the sand with their roots
3. The stability and nutrients accumulate, so more plants grow e.g. marram grass which traps sand
4. Nitrogen-fixing plants begin to colonise, increase nutrients in the sand, creates a habitat copable for more plants


Give an example of pioneering plants on a sea bed

sea rocket (Cakile maritima) and prickly sandwort (Salsola kali)


What kind of conditions to pioneering plants have to be able to withstand on sand

salt water spray
lack of fresh water
unstable sand


How do mini-sand dunes form? (stage 2 of succession)

Windblown sands build up around the bases of pioneering plants


Give an example of plants that begin to colonise once sand dunes begin to accumulate nutrients

sea sandwort (Honkenya peploides) and sea couch grass (Agropyron junceiforme)
then sea spurge (Euphorbia paralias) and marram grass (Ammophila arenaria)


How does sea couch grass help to stabalise sand?

As it has underground stems


What is special about marram grass, and helps succession along?

its shoots trap wind-blown sand and as the sand accumulates the shoots grow taller to stay above the growing dune.


Give examples of plants that begin to colonise once the marram grass has made enough of a sand dune

hare's foot clover (Trifolium arvense) and bird-foots trefoil (Lotus corniculatus)
(Members of the bean family (legumes))


How do legume plants aid the succession of sand dunes?

The bacteria in the root nodules convert nitrogen into nitrates, and then when more nitrates are available


Explain the meaning of primary succession

a directional change in a community of organisms over time, beginning from bare ground


Explain the meaning of pioneer community

The living organisms which first start to colonise on bare ground


Explain the meaning of climax community

The stable community that emerges at the end of a process of succession


Compare and contrast the process of succession on bare rock and on a sand dune

Pioneering community: BR- lichens/algae SD- higher plants
Climax community: both woodland
BR- no windblown sand SD- dfg


Explain why all stages of succession are visible in a sand dune

Because the sea deposits sand on the beach and the sand nearest the sea is deposited more recently than that further away
Sand just above the water mark is at the start of the succession whereas the sand further away hosts a climax community
By walking up the beach and through the dunes its possible to see the process of succession