Classification What is a dichotomous key It is

Classification

What is a dichotomous key? It is a series of paired statements (that have a yes or no answer) that lead you to the correct name of a given item.

What is a dichotomous key used for? It is used as a tool to identify organisms in our world.

Why are organisms classified? • It’s a way to sort and group organisms for easier study – helps us to see patterns in nature. • Groups things based on similar characteristics. • When an organism belongs to a certain group, a scientist will know some basic facts about that organism. • Understand the relationship between the species.

Organisms are classified by their: 1. 2. 3. 4. 5. Physical structure (how they look) Evolutionary relationships Embryonic development Genetic similarities (similarities in DNA) Biochemical similarities

The history of the current method used to classify organisms • Taxonomy – the study of scientific classification. • Aristotle (384 – 322 BC) – “The Father of Science. ” • Grouped animals according to certain similarities such as those that swam and those that lived on land OR those that flew and those that could not fly.

The history of the current method used to classify organisms • During the 1500’s, two scientists - Andrea Cesalpino and Gaspard Bauhin - worked separately to classify plants.

The history of the current method used to classify organisms • Carolus Linnaeus (1700’s) tried to classify all living things based on shape AND structure. Our system today is very similar to the one he developed. • He developed the concept of binomial nomenclature by giving each species a twopart scientific name (genus species).

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Our classification System • • Domain Kingdom Phylum Class Order Family Genus Species Do kids play cards or flip gooey spoons? Now, make your own pneumonic device.

Some characteristics used to classify organisms into Kingdoms • • • Type of cell Number of cells Energy Movement Reproduction methods

Type of Cell

Number of cells Unicellular Multicellular

Chemotrophs: Autotrophs Energy Heterotrophs:

Movement

Movement

Asexual Reproduction

Sexual Reproduction

Some of the characteristics used to classify animals into lower taxanomic (classification) levels (i. e. phylum, class, order, family, genus, species) • Has a backbone/no backbone • Endothermic (warm-blooded)/Exothermic (cold-blooded) • Carries their young/lays eggs • Has fur/scales/feathers • Eats meat/does not eat meat

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