Theory question 103
Ecosystem and Ecological Factors(a)(i) What is an ecological niche? (ii) State five roles played by a mango tree in its ecological niche.
(b)(i) State two reasons why ecologists use sampling techniques in population studies. (ii) State four examples of sampling techniques used in the population studies.
(c) Name four types of fingerprints in humans.
(d)(i) Name the plant used by Gregor Mendel in his experiment. (ii) State two reasons why the plant named in 3(d)(i) was used.
Show the model answer
(a)(i) An ecological niche is the role or functional position of an organism in its habitat: where it lives, what it feeds on, what feeds on it and how it affects the environment.
(ii) Any five: producer — makes food by photosynthesis; provides fruits as food for animals and humans; provides shelter/nesting sites for birds, insects; gives shade; releases oxygen and absorbs CO2; adds leaf litter/humus to the soil; roots hold the soil and prevent erosion; host to epiphytes and parasites; transpiration adds water vapour to the air.
(b)(i) It is impossible or too time-consuming to count every organism in a large area; sampling saves time, labour and cost; it gives a good estimate of the whole population; avoids destroying the habitat.
(ii) Any four: quadrat; line transect; belt transect; capture–mark–recapture; pitfall trap; sweep net; pooter.
(c) Arch; loop; whorl; compound (composite).
(d)(i) Garden pea (Pisum sativum).
(ii) Any two: it has many clear contrasting characters; it is normally self-pollinating, so pure lines are easy to keep; it can be cross-pollinated by hand; short life cycle; produces many seeds; easy to grow.
For (a)(ii) think of what the tree does for other organisms and the environment.