Dichotomous Keys For anyone who doesn't specialise in studying a particular group of organisms, it can be very?difficult to identify, or ID, a species?when working in the field Correctly identifyin...
Cladistics & Reclassification The development of?DNA sequencing technology?means that classification can now be carried out on the basis of?evolutionary relationship Organisms classified in thi...
Clades The term?clade?can be defined as A group of organisms that have all descended from a common ancestor Cladistics?is the branch of science in which scientists put organisms into clades It invo...
Animal Phyla Features Animals are?multicellular,?eukaryotic?organisms They are?heterotrophs?and most have a?nervous system?that enables responses to the surrounding environment There are over?30 an...
Plant Phyla Features All plants belong to the?plant kingdom Within the plant kingdom are several?phyla?(singular?phylum) Some plant phyla are small E.g. the Glaucophytes contain only 70 species and...
Examples of Classification Biological classification involves putting organisms into?groups, or?taxa?(singular?taxon) The taxa form a?hierarchy A?hierarchical system?is one in which?larger groups c...
Binomial System The?diversity of life?on Earth is vast, and is known as?global biodiversity The extent of global biodiversity is such that scientists can only?estimate?the total number of species p...
Examples of Natural Selection Because evolution by?natural selection?generally happens over?millions of years,?it is difficult to see it taking place, and we often have to rely on evidence from the...
Overproduction of Offspring The?number of offspring, or young, produced in each breeding event?differs between species Some species produce?small numbers?of young, e.g. elephants usually give birth...
