Classification and Biodiversity

• Classification is the organisation of organisms into groups.
• Organisms are often classified into groups based on similar physical features.
• The classification of organisms is important because it makes it easier to identify organisms and aids communication between scientists.
• Organisms are given scientific names to facilitate universal communication.
• Scientific name given in two words, first name (genus) begins with a capital letter, second name (species) begins with a lowercase letter, words written in italics, or if handwritten underlined.
• Adaptations are characteristics of an organism that increase its chance of survival, they are maintained by natural selection.
• There are two types of adaptation: Morphological, which are structural adaptations such as camouflage, and Behavioural, which are aspects of behaviour that aid survival such as bird calls.
• Competition occurs between members of the same species for the same food and also between members of different species for space.
• Competition, along with predation, disease, and pollution, limits population sizes within a community and is the driving force of evolution by natural selection.
• Biodiversity is a combination of species diversity, genetic diversity, and ecosystem diversity.
• Biodiversity is important for a number of different reasons: it safeguards future food supplies by maintaining food chains important to humans, it reduces damage to food chains, it protects valuable future resources such as fuels and paper, it creates stable ecosystems that are more likely to be able to adapt to future environmental change, it provides aesthetic reasons, it benefits communities through ecotourism, and it can be maintained by protection of endangered species, conservation schemes, reforestation, sustainable farming, minimising greenhouse gas production, legislation, and seed b
• Biodiversity can be estimated by sampling areas of an ecosystem.
• When choosing a sample area, ensure it is of a sufficient size, avoid bias when choosing sample areas, and the sampling method has no effect on the results.
• A quadrat is a square frame divided into smaller square sections and can be used to investigate the biodiversity of an area by counting members of each species present in the quadrat and estimating the % coverage of each species.
• A quadrat can be used as follows: position two 20 m tape measures at right angles along the border of the sample area, use a random number generator to randomly select two numbers which serve as the x-coordinate and y-coordinate with the tape measures as the axis, at each location, place the lower left hand corner of the quadrat at the coordinate point, identify and record the numbers of each species present or the % coverage of each species.
• The capture-recapture method is used to sample animal populations by capturing a number of individuals of one species, marking the captured individuals, releasing them back into the sample area, and after a suitable period of time, recapturing more individuals of the same species.
• Accurate results are obtained only when there is adequate time between first and second samplings, no significant movement of the population into or out of the area during the time between samples, the marking method does not adversely affect animal survival, the marking method does not affect the probability of recapture, and marks do not rub off.
• Biological control is when a new organism (often described as an ‘ alien species ’) is deliberately introduced into an ecosystem to control a pest or pathogen.
• An alien species is a new species that is introduced into an area (where it is not naturally found).
• There are many problems associated with the introduction of alien species: the alien species population may grow out of control if they do not have a natural predator, they may outcompete or prey on existing species, and they may carry new diseases that could infect existing species.
• Detailed research and trials must be carried out before the introduction of alien species into an area.
• Balancing the need for resources with the need to preserve the biodiversity of ecosystems is essential to protect ecosystems and endangered species, while still maintaining quality of life for humans.