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biology 0610printed 7 · PDF 7
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⦁ Respiration- chemical reactions in cells that break down nutrient molecules and release
energy for metabolism
⦁ Sensitivity- the ability to detect and respond to changes in the internal or external
environment
⦁ Growth- a permanent increase in size and dry mass
⦁ Reproduction- the processes that make more of the same kind of organism
⦁ Excretion- the removal of the waste products of metabolism and substances in
excess of requirements
⦁ Nutrition- the taking in of materials for energy, growth and development
This can be better remembered through the acronym MRS GREN. These
characteristics are part of every single living organism.
How organisms are classified
⦁ A species is defined as a group of organisms that can reproduce to produce fertile
offspring
⦁ Species can be classified into various groups by the features that they share anatomically
and morphologically.
⦁ Organisms are named using the binomial naming system (an internationally agreed
upon naming system) where each name consists of 2 words; the first being of the genus
(given by a capital letter) and the next of the species (starting with a lower-case letter)
• The sequence of classification starts from Kingdom and ends at Species shown in
the diagram
⦁ Classification systems aim to reflect evolutionary relationships
⦁ Traditional classification systems used to classify using the anatomy or morphology
⦁ However, it had many limitations
⦁ Thus, DNA classification is used to classify organisms today