Male orange-tip butterflyAnimals are a diverse group of living organisms, with an estimated 1.5 million species worldwide that survive in a wide range of habitats from the deepest oceans to the highest mountains.
Approximately 34,650 species occur in Britain. The relationships between different groups of animals are very complex. However, animals can be divided into two main groups: the animals with a backbone can be called vertebrates and the animals that do not have a backbone can be called invertebrates.
Vertebrates
Vertebrates are animals that have a backbone and skeletal structure that supports the body and protects the internal organs. Although there are fewer vertebrate than invertebrate species, they are more complex organisms. Vertebrates range in size from the blue whale, the largest animal on earth at over 30 metres long, to mice and shrews that may be less than 5 cm long. Mammals, birds, reptiles (e.g. snakes) and amphibians (e.g. frogs) are all vertebrates. To find out more about these groups in the Yorkshire Dales please follow the links provided.
Invertebrates
Invertebrates are animals that do not have a back bone or a supporting skeleton. Instead, a hard outer covering known as an exoskeleton (an external flexible layer of cells) supports and maintains the body shape. Invertebrates have been particularly successful in adapting to live in a wide range of different habitats. Invertebrates range in size from micro-organisms, which are too small to be seen with the naked eye, to much larger animals such as the squid. Scientists estimate that invertebrates make up approximately 95% of all the animals on earth. Insects (e.g. butterflies and moths), crustaceans (e.g. crayfish), millipedes, centipedes, spiders, earthworms and molluscs (e.g. snails) are all invertebrates. To find out more about butterflies and moths and some other invertebrates in the Yorkshire Dales please follow the links provided.
