#13 Summary of Classification of Living things

Here is a brief summary of previous topics. 

• All living things have 7 characteristics:  Nutrition, Respiration, Growth, Excretion, Movement, Reproduction and Sensitivity.

• Living organisms are classified into groups according to how closely related they are. Each species of organism is given a unique two-word Latin name called a binomial. The first word of the binomial is the genus and the second word is the species.

• Vertebrates are classified into 5 classes: fish, amphibians, reptiles, birds and mammals. They each have their own distinctive set of features. E.g. amphibians have a smooth skin, fish and reptiles have scales, birds have feathers and scales, and mammals have hair.

• Arthropods are invertebrates with joined legs and segmented bodies. They can be further classified into insects, arachnids, crustaceans and myriapods. 

• Annelids are worm with segmented bodies but no legs.

• Nematodes are worms with unsegmented bodies.

• Molluscs have unsegmented bodies, and often have a shell.

• Bacteria are single-celled organisms whose cells do not have nuclei.

• Fungi include moulds, mushrooms and toadstools. They have cells with cell walls but do not photosynthesise.

• Viruses are not generally considered to be alive at all. They are not made of cells and cannot carry out any of the characteristics of living things on their own.

• Flowering plants can be classified in to monocotyledonous plants and dicotyledonous plants. Monocots have seeds with one cotyledon, and their leaves often have parallel veins. Dicots have seeds with two cotyledons, and their leaves generally have branching veins.

• A dichotomous key is a set of paired contrasting descriptions which lead you through to the identification of an unknown organism.