(a) Explain the following terms:
(i) Producer
(ii) Consumer
(iii) Community
(iv) Decomposer.
(b) List four characteristics each of:
(i) Trees of the Tropical Rain Forest IP
(ii) Trees/Shrubs of the Savanna.
Explanation
(a)(1) Producer: This is a green plant or autotroph which traps the energy of sunlight, radiant energy or solar energy and converts it to chemical energy in order to form organic compounds and photosynthesis using CO2 and water or simple inorganic substances as raw materials. It forms the starting point or origin of every food chain.
(ii) Consumer: This is an organism which derives its nutrients, energy and food from eating plants directly or indirectly. In other words, it is an organism which depends on other organisms for food, energy and nutrients. All consumers are heterotrophs and they lack chlorophyll. They are either animals that derive their nutrients, food and energy from eating plants directly (e.g. cow and sheep) and are called herbivores or primary consumers or they are other animals (e.g. cats, hyenas, lions and leopards) that eat herbivores and thus derive energy indirectly from the producers. These are called carnivores or secondary consumers.
(iii) Community: This refers to a group of plants and animals that occupy a given area and are adaptable to the conditions of their environment. They are interdependent i.e depend on one another and can continue to live successfully and reproduce new offspring.
(iv) Decomposer: Decomposers are fungus or bacteria which lives saprophytically or feed on dead remains of plants, animals and organisms leading to or resulting in recycling of nutrients by breaking down organic matters to produce soluble nutrients which are absorbed by plants.
(b)(i) Characteristics of trees in Tropical Rain Forest:
(a) The trees are predominantly woody.
(b) They are stratified.
(c) Some are called “emergents, ‘ and attain a height of over 60 metres.
(d) They have straight columnar trunks with branches only at the crown.
(e) They have buttresses.
(f) They have thin smooth barks without conspicuous fissures or lenticels.
(g) They usually have dark green leaves that are broad,large and leathery.
(h) The leaves are with entire margin, having drip tips or extended tips.
(i) The trees form canopies at the crown and cast dense shade on the underneath.
(j) They have cauliflory or flowers attached directly to trunks and branches – not on inflorescence stalks.
(k) Some of the trees have stilt roots.
(ii) Characteristics of trees and shrubs of the Savanna:
(a) The trees and shrubs are scattered and woody.
(b) They have narrow leaves and few stomata.
(c) Their leaves have thick cuticle.
(d) The trees are not usually very tall (10-50 metres).
(e) They have gnarled, twisted or crooked trunks with fissured, fire-resistant or corky barks
(g) Most of the trees are deciduous, they shed leaves during dry season.
(h) They also have long taproot with extensive root system.