Ecosystem

Question 3:A study has been carried out to estimate the population size of fish in a pond. The steps of the study are as below:• Fish are captured, marked and released back into the pond.• After a week, fish are recaptured and counted.• The number of marked fish is recorded.(a) What is the most suitable … Read more

Question 1:Figure 1 shows changes of plant sequence in a mangrove area.(a) Name the plants in each of the zones: 1, 2 and 3.(b)(i) Name the process that causes plants in Zone 1 to distribute to a new habitat.(b)(ii) Name the process that causes plants in Zone 1 to be replaced by plants in Zone … Read more

Question 1:An ecosystem has a population size, population density and population distribution.(a) What is the difference between population size and population distribution?(b) State the factors that can affect population distribution.(c) State the patterns of the population distribution. Explain. Answer:(a) Population size is the number of organisms present in a population whereas population distribution is the … Read more

Activity 9.5:Pleurococcus sp. is a type of green algae growing on areas that are protected from the scorching sunlight to form a slimy layer on places such as tree barks, stones and moist soil. This algae can reproduce very fast through vegetative cell division by binary fission. Pleurococcus sp. is a sphere-shaped unicellular organism which … Read more

Activity 9.4:AimTo carry out a field study to estimate the population size of animalsApparatusPaint brush, Indian ink or nail polish, a pen, papersProcedure1. Choose a suitable area in the school compound where you can carry out a study.2. Identify the type of animals which is abundant in that area to become a sample.3. Capture five … Read more

Activity 9.3:AimTo carry out a field study to estimate the population size of plants in the school fieldApparatusA quadrat measuring 1 m × 1 m, a pen, a note bookProcedure1. Identify a plant species X present in the school field.2. A quadrat measuring 1 m × 1 m is randomly placed in a part of … Read more

Question 1:Give the definitions of each of the following:(a) Species(b) Population(c) Community Answer:(a) A group of similar organisms that can interbreed with each other and produce offspring.(b) A group of organisms of the same species and live in the same habitat.(c) Different types of organisms that live in the same habitat and interact with each … Read more

Experiment 9.1 – The Effects of Intraspecific and Interspecific Competitions among Organisms:Problem statementWhat are the effects of intraspecific and interspecific competitions among organisms?AimTo study the effects of intraspecific and interspecific competitions among organismsHypothesisIf the competition among organisms is high, the growth of organisms becomes slow.VariablesManipulated variable: Types of seedsresponding variable: Height of seedlingsConstant variable: Amount … Read more