19.6 Succession

Question 1

define succesion

Answer 1

describes changes in species that occupy a particular area (over time)
predictable and orderly change in the composition of structure of an ecological community

Question 2

define climax community

Answer 2

balanced equilibrium of species with few (if any) new species replacing those that have become established
many species flourish and there is much biodiversity
(determined by limiting abiotic factor)

Question 3

how might a new species change the environment

Answer 3

1. less suitable for the existing species- new species will outcompete existing one
2. more suitable for other species with different adaptations- this species may be outcompeted by the better adapted new species

Question 4

features of a pioneer species

Answer 4

asexual reproduction- organism can rapidly multiply to build up population
production of vast quantities of wind dispersed seeds or spores- easily reach isolated situations (volcanic islands)
rapid germination of seeds on arrival
ability to photosynthesise- often light is available and other food is not. not dependent upon animal species
ability to fix nitrogen from atmosphere- few nutrients
tolerence to extreme conditions

Question 5

common features that emerge from succesion

Answer 5

1. non living (abiotic) environment becomes less hostile e.g. soil forms, more nutrients, plants provide shelter ->
2. greater number and variety of habitats and niches ->
3. increased biodiversity (different species occupy the habitat ->
4. more complex food webs ->
5. increased biomass

Question 6

secondary succesion is when

Answer 6

land that has already sustained life id duddenly altered (e.g. by land clearance)
process by which ecosystem returns=secondary succesion

Question 7

summary

Answer 7

barren land -> primary colonisers e.g. lichen -> secondary colonisers e.g. mosses -> tertiary colonisers e.g. grass -> scrubland e.g. shrubs, small trees -> climatic climax e.g. woodland

Question 8

e.g. of climax community in UK

Answer 8

deciduous oak woodland

Question 9

types of succession

Answer 9

primary- begins in areas where no soil is initially present

secondary- begins in areas where soil is already present