5.5 Classification

What is a dichotomous key? Give an example. How did the Greek philosopher Aristotle classify organisms? What were the problems with this method? What is taxonomy? What is the binomial System of classification? Who came up with this system? When? What is genus? What is species? What are the 7 levels of hierarchy in classification? Give one example of an animal and plant and their whole hierarchy of classification. What are the 5 kingdoms? What are the characteristics of the plant kingdom? Give examples and characteristics (physical, simple external recognition) for Bryophyta, Filicinophyta, Coniferophyta, Angiospermophyta. What are the characteristics of the animal kingdom? Give examples and characteristics (physical, simple external recognition) for Porifera, Cnidaria, Platyhelminthes, Annelida, Mollusca and Arthropoda. What is a dichotomous key? Give an example.

Assessment Statements Outline the binomial system of classification List seven levels in the hierarchy of taxa- kingdom, phylum, class, order, family genus and species- using examples from two different kingdoms for each level Distinguish between the following phyla of plants, using simple external recognition features: bryophyta, filicinophyta, coniferophyta, angiospermophyta. Distinguish between the following phyla of plants, using simple external recognition features: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda. Apply and design a key for a group of up to 8 organisms.

You failed your Latin exam You failed your Latin exam!? But sweetie all of your friends’ names have Latin roots!

Why Classify Biological classification attempts to arrange living organisms into groups that enable them to be identified easily and that show evolutionary links between them. The system we use today was originally devised by the Swedish scientists Carolus Linnaeus (1707-1778).

It allows us to group similar organisms

The Binomial System of Classification The classification of living organisms is simply a method of organizing them into groups to show similarities and differences. (384-322 BC) Greek philosopher Aristotle classified organisms into two groups- plants and animals. This was a useful starting point, but as the two main groups were sub-divided, problems appeared. At this time organisms were considered unchanging and evolutionary concepts weren’t understood. Organisms later discovered didn’t fit into this scheme.

Birds were separated into a group defined as “Feathered animals that can fly” So no place could be found for the flightless birds such as a kiwi or ostrich. Bacteria, which were unknown at the time, weren’t included at all.

1735, Carolus Linnaeus adapted Aristotle’s work, and his system forms the foundation of modern taxonomy. Taxonomy is the science od identifying, naming and grouping organisms. Linnaeus gave each organism two Latin names- the first part of the name is the genus name and the second part is the species names. The binomial, or two-part, name for the American grizzly bear is Ursus americanus A polar bear would be Ursus maritimus

It is important that when scientists in Mongolia work on a species, a scientist in Brazil knows which one. Anemone Anemone He used Latin for his names because it was the language of medicine and science, and it is unchanging.

Ursus americanus Ursus maritimus The genus part of the name indicates a group of species that are very closely related and share a common ancestor. The species is usually defined as a group of individuals that are capable of interbreeding to produce fertile offspring.

Linnaeus devolved a structure in his classification system. He grouped birds into birds of prey, wading birds and perching birds. Although it’s possible to group living things in many different ways a hierarchical classification system has emerged that all biologist use.

Kingdom Phylum Class Order Family Genus Species There are 7 levels of Classification Kingdom Phylum Class Order Family Genus Species Make up a pneumonic to remember this list in order. King Philip Comes Over For Great Sausages.

Animalia Plantae Fungi Protist Bacteria The 5 Kingdoms No cell walls Cellulose cell walls Chitin cell walls Many types of cell wall NAG-NAMA cell walls Multi-cellular Single + Multi-cellular Single cellular Heterotroph Autotrophs Saprotroph Many feeding types

Polar Bear Lemon Tree Kingdom Animalia Plantae Phylum Chordata Angiospermata Class Mammalia Dicoyledoneae Order Carnivora Geraniales Family Ursidae Rutaceae Genus Ursus Citrus Species Maritimus limonia

Filicinophyte – The Ferns Coniferophyte – The Conifers A closer look at Plants: There are 4 phyla: Bryophyte – The mosses Filicinophyte – The Ferns Coniferophyte – The Conifers Angiospermophyte – The flowers

Bryophytes – The mosses Usually small and grow in damp places Simple non, vascular (no xylem and phloem.) No proper roots but have rhizoids Reproduce with spores (in a capsule on a stalk). Male gamete swims to female!

Filicinophytes – the ferns Group includes club mosses, horsetails and ferns Has stems roots and leaves. Because of support from woody tissue they can grow up to 5m Reproduces by spores (underside of the leaves). Male gamete swims to female. Some have fibrous roots, while others produce an underground stem called a rhizome.

Coniferophytes – The conifers Includes shrubs, or trees such as pine, fir, cedar which are large and evergreen, some of the tallest trees in the world. Truly vascular. Reproduce with pollen. Make cones with seeds inside. Leaves are needle shaped to conserve water.

Angiospermophytes- Flowering plants Contains flowering plants, which are pollinated by wind or animals. Range from small low-lying plants to large trees. Many are important crops Have proper flowers which produce pollen. All produce seeds which are associated with nuts and fruit. Truly vascular.

The Animal invertebrates in detail Invertebrates are animals without backbones there are 6 phyla: Porifera – sponges. Cnideria - corals. Platyhelminthes – flat worms. Annelida – segmented worms. Mollusca – snails, octopi. Athropoda – insects, spiders, crustaceans Animal kingdom are characterized by being able to move and getting nutrients by eating plans, other animals or both. Animals are divided into two groups- with a backbone (vertebrates) and without (invertebrates).

Porifera – the sponges This group contains sponges. They have different types of cells, but no real organization into tissues No clear symmetry All are aquatic Pump water through numerous pores and filter food. No nerves or muscular tissue.

Cnideria – Corals, hydra, jellyfish These are sea anemones, corals, jellyfish. All most all marine, cells are organized into tissues in two body layers They feed on other animals by stinging them with nematocyst They have a mouth t take in food and use the same opening to get rid of waste.

Platyhelminthes- flatworms These have 3 layer of cell and have a body cavity with a mouth and anus Some are free living while others are parasites. Flattened appearance, most are small but tapeworms may grow to several meters.

Annelida – segmented worms Contains earth worms and leeches, Some are aquatic, others in the soil. All have a simple gut with a mouth at one end and an anus at the other. Earthworms are important to agriculture because burrowing aerates the soil.

Mollusca – snails, octopi Have a mouth and anus. Most have a calcium carbonate shell. Bilateral symmetry. Hard rasping ‘radula’ is used for feeding.

Athropoda – insects, spiders, crustaceans Largest animal phylum. All have exoskeleton made of chitin, places restrictions on how large they can get because they have to shed it in order to grow. Segmented bodies and jointed limbs. Over a million different types and many more being discovered.

A dichotomous key is a series of steps, involving a decision, that can be used to identify unknown organisms. They prompt us to decide, through careful observation, whether or not a specimen displays a particular visible feature. When constructing a key examine each specimen and choose a characteristic that is present in about half and absent in the other. Now split those groups in half based on a visible characteristic.