ecosystems and nutrient cycles

Question 1

    Anolis sagrei is a species of lizard that is found on some of the smallest Caribbean islands. Describe how you could use the mark-release-recapture method to estimate the number of Anolis sagrei on one of these islands. (4)

Answer 1

Capture sample, mark and release

Method of marking harmless to lizard

Leave enough time for lizards to distribute on island before collecting second sample

(Number in first sample x number in second sample)/ number recaptured.

Question 2

Succession occurs in natural ecosystems. Describe and explain how succession occurs. (5)

Answer 2

Colonisation by pioneer species

Change in environment

Enables other species to colonise

Change in diversity

Less hostile environment/ more stable

Climax community

Question 3

what are some assumptions made by mark release recapture

Answer 3

• mark does not affect survival
• no migration in/out of the community
• little deaths/births
• assume mark does not come off