The ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
Growth
A permanent increase in size and dry mass by an increase in cell number or cell size or both
Excretion
The removal from organisms of the waste products of metabolism, toxic materials and substances in excess of requirements
Nutrition
The 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
Autotrophs
Photosynthetic plants that are usually the first organisms in food chains
Species
A group of organisms that can reproduce to produce fertile offspring
Binomial system
An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and the species
Organisms can be classified into groups by the features that they share
Classification systems aim to reflect evolutionary relationships
Classification is traditionally based on studies of morphology and anatomy
Binomial system
The scientific name of an organism is made up of two parts showing the genus and the species
The sequences of bases in DNA and of amino acids in proteins are used as a more accurate means of classification
Organisms which share a more recent ancestor have base sequences in DNA that are more similar than those that share only a distant ancestor
Features in cells of all living organisms
Cytoplasm
Cell membrane
DNA as genetic material
Ribosomes for protein synthesis
Enzymes involved in respiration
Five kingdoms of classification
Animal
Plant
Fungus
Prokaryote
Protoctist
Animals
Multicellular organisms whose cells have no cell walls or chloroplasts
Most animals ingest solid food and digest it internally
Arthropods
Jointed limbs
Hard, firm external skeleton called a cuticle
Segmented bodies with flexible joints between segments
Distinct head, thorax and abdomen regions
Crustacea
Exoskeleton and jointed legs
Two pairs of antennae
Compound eyes
Jointed limbs on each body segment, modified on head segments
Insects
Segmented bodies with firm exoskeleton
Three pairs of jointed legs
Compound eyes
Two pairs of wings
Head, thorax and abdomen regions
Only one pair of antennae and three pairs of legs, no limbs on abdomen
Arachnids
Body divided into cephalothorax and abdomen
Four pairs of limbs on cephalothorax
Pedipalps used in reproduction
Chelicerae used to pierce and paralyse prey
Several pairs of simple eyes
Myriapods
Head and segmented body not obviously divided into thorax and abdomen
Pair of legs on each body segment, abdominal segments fused in pairs
One pair of antennae and simple eyes
Vertebrates
Have a vertebral column
Poikilothermic (cold-blooded) or homoiothermic (warm-blooded)
Fish
Poikilothermic (cold-blooded) vertebrates
Streamlined shape
Covered in overlapping scales
Have fins
Breathe through filamentous gills
Reproduce sexually with external fertilisation
Homoiothermic
Constant temperature
Internal regulatory mechanisms keep the body temperature within narrow limits
Fish
Poikilothermic (cold blooded) vertebrates
Smooth, streamlined shape
Covered with overlapping scales
Have fins
Breathe through filamentous gills
Reproduce sexually with external fertilisation
Amphibia
Poikilothermic (cold blooded) vertebrates
Have four limbs and no scales
Spend part of life in water and part on land
Moist skin with capillaries to exchange gases
Have lungs but no diaphragm or ribs
Reproduce with external fertilisation
Reptiles
Land-living vertebrates
Dry, scaly skin that resists water loss
Lay eggs with tough, parchment-like shells
Can regulate temperature to some extent by basking in the sun
Birds
Homoiothermic (warm blooded) vertebrates
Flexible vertebral column in neck, rest fused for rigid structure
Covered in feathers of different types
Have four limbs, with forelimbs modified into wings
Have beaks
Reproduce with internal fertilisation and lay hard-shelled eggs
Mammals
Homoiothermic (warm blooded) vertebrates
Have hair rather than feathers
Have a diaphragm for breathing
Have mammary glands to produce milk for young
Give birth to live young rather than laying eggs
Undergo internal fertilisation and development in the uterus
Ferns are land plants with quite highly developed structures, including stems, leaves, roots, vascular tissue, and multicellular roots
Ferns
Produce gametes but no seeds
Reproduce by producing single-celled spores from sporangia on the leaves
Monocotyledons
Flowering plants with only one cotyledon in their seeds, often with long, narrow leaves and parallel leaf veins
Dicotyledons
Flowering plants with two cotyledons in their seeds, often with broad leaves and branching leaf veins
Most fungi are made up of thread-like hyphae rather than cells, and have many nuclei distributed throughout the cytoplasm
Bacteria are single-celled organisms with a cell wall made of proteins, sugars and lipids, and a single circular chromosome not enclosed in a nuclear membrane
Protoctists are single-celled organisms with their chromosomes enclosed in a nuclear membrane
Some protoctists, like Euglena, have chloroplasts and can photosynthesize, while others, like Amoeba and Paramecium, take in and digest solid food
Circular strand of DNA
Not enclosed in a nuclear membrane
Coiled up to occupy part of the cell
Individual bacteria
May be spherical, rod-shaped or spiral
Some have filaments called flagella projecting from them
Flagella can flick and move the bacterial cell about