1. Characteristics and classification

1.1 The characteristics of living things

Describe the characteristics of living organisms by defining the terms:

• movement as an action by an organism or part of an organism causing a change of position or place

• respiration as the chemical reactions in cells that break down nutrient molecules and release energy for metabolism

• sensitivity as the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses

• growth as a permanent increase in size and dry mass by an increase in cell number or cell size or both

• reproduction as the processes that make more of the same kind of organism

• excretion as removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements

• nutrition as taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds and ions and usually need water

1.2 Concept and use of classification

• State that organisms can be classified into groups by the features that they share

• Describe a species as a group of organisms that can reproduce to produce fertile offspring

• Describe the binomial system of naming species as an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species

• Construct and use dichotomous keys based on identifiable features

• Explain that classification systems aim to reflect evolutionary relationships

• Explain that the sequences of bases in DNA are used as a means of classification

• Explain that groups of organisms which share a more recent ancestor (are more closely related) have base sequences in DNA that are more similar than those that share only a distant ancestor

1.3 Features of organisms

• List the features in the cells of all living organisms, limited to cytoplasm, cell membrane and DNA as genetic material

• List the main features used to place animals and plants into the appropriate kingdoms

• List the main features used to place organisms into groups within the animal kingdom, limited to:

  • the main groups of vertebrates: mammals, birds, reptiles, amphibians, fish

  • the main groups of arthropods: myriapods, insects, arachnids, crustacean.

• List the features in the cells of all living organisms, limited to ribosomes for protein synthesis and enzymes involved in respiration

• List the main features used to place all organisms into one of the five kingdoms: Animal, Plant, Fungus, Prokaryote, Protoctist

• List the main features used to place organisms into groups within the plant kingdom, limited to ferns and flowering plants (dicotyledons and monocotyledons)

• List the features of viruses, limited to protein coat and genetic material.

1.4 Dichotomous keys

• Construct and use simple dichotomous keys based on easily identifiable features