WJEC GCSE Biology 2.1 Classification and Biodiversity Exam Questions

About WJEC GCSE Biology 2.1 Classification and Biodiversity

Classification and biodiversity opens Unit 2 of WJEC GCSE Biology. You need to group organisms by shared features (flowering and non-flowering plants, vertebrates and invertebrates) and explain why scientific names are used. The topic covers morphological and behavioural adaptations and the factors that change population size, such as competition, predation, disease and pollution. You must explain what biodiversity is, why it matters and how it is protected, and use quadrats and capture-recapture to estimate populations. Biological control and alien species complete the topic. The specified practical on distribution and abundance means sampling technique questions are common.

What you need to know

• Classification Organisms are classified by shared features into groups such as flowering and non-flowering plants, and vertebrates and invertebrates. Scientific (binomial) names avoid confusion because common names vary between places and languages.
• Adaptations Morphological adaptations are features of structure (e.g. thick fur); behavioural adaptations are actions (e.g. hibernating or migrating). Both increase the chance of survival in a habitat.
• Population size Populations are affected by competition for resources such as food, water, light and space, by predation, by disease and by pollution.
• Biodiversity Biodiversity is the variety of species in an area. It is important for stable ecosystems, food and medicines, and is protected by measures such as legislation, protected areas and conservation.
• Sampling Quadrats placed at random, or along a transect, estimate abundance or percentage cover. Enough samples must be taken to be representative. Investigating factors affecting the distribution and abundance of a species is a specified practical.
• Capture-recapture and control Population = (number marked in first sample x number in second sample) / number marked in second sample. Biological control uses a natural predator or parasite to control a pest; alien (introduced) species can outcompete native wildlife.

Common mistakes in 2.1 Classification and Biodiversity

• Placing quadrats where the organism is easy to see. Quadrats should be placed randomly (e.g. using random numbers for coordinates) to avoid bias.
• Assuming capture-recapture works whatever happens. It assumes no deaths, births or migration between samples and that marks do not affect survival or come off.
• Defining biodiversity as the number of organisms in an area. It is the variety of different species (and genetic variety), not the total number of individuals.
• Saying biological control has no risks. The control species may eat other organisms or become a pest itself, as happens with some alien species.

Try three 2.1 Classification and Biodiversity exam-style questions