Essay on Biology: Classification of Life

Submitted By Katytucker
Words: 1466
Pages: 6

Characteristics of a living thing

Movement
Reproduction
Sensitivity
Growth
Respiration
Excretion
Nutrition

The Organisations of life
Biosphere
Ecosystem
Community
Population
Species
Organ system
Organ
Tissue
Cell = Basic building block of all living things
Organelle
Molecule
Atoms

Notes on: Cells
Living organism may be made up of one cell: i.e. unicellular
Living organisms, made up of numerous cells: i.e. multicelluar
All cells have similar structures and chemicals

Cell membrane: controls what goes in and out of a cell. Made up of biphosphorus fatty layer with proteins

Cytoplasm: Jelly interior, similar to seawater

Nucleus: Control Centre of cell. Made up of nucleic acid and compounds such as RNA and DNA

Classification of Living Organisms
All living organisms can be placed into 5 (or possibly 6) broad groupings called kingdoms. 1. Plantae kingdom- Plants 2. Animalia Kingdom- Animals 3. Fungi Kingdom- Fungus, Moulds, Mushrooms, yeast 4. Protista Kingdom- Protozoan’s = single celled or unicellular organisms 5. Monera Kingdom- Bacteria (Maybe split into two separate kingdoms: Kingdom- Archaebacteria Kingdom- Eubacteria
Prokaryotes
Have cells without a membrane bound nucleus
Monera:
Archaebacteria
Eubacteria
Eukaryotes
Have Cells with a Membrane bound nucleus
Plantae
Animalia
Fungi
Protista

Number of different organisms belonging to the group decreases as you go down classification rank
Similarities between different organisms in each group increases as you go down classification rank
Scientific names for organisms are written as:
Genus Species
Kingdom
Phylum
Class
Order
Family
Genus
Species

The Animal Kingdom/ Kingdom Animalia
Distinguishing Characteristics

* Heterotrophic

* Reproduce predominantly by sexual reproduction

* Mobile – Move from A-B

* Multicelluar - Specialised cell

* Eukaryotic – membrane bound nucleus/organelles

Invertebrates.
Phylum: Porifera
Example- Sponge, Tube sponge * Sessile- Adults do not move location * 1cm-2m in height. * Filter Feeders- Filter water, take all particles out and feed on them * Aquatic- Live only in water (Mostly marine) * No nerves, muscles or organs * No body symmetry

Phylum: Cnideria
Example- Jellyfish, Brain coral * Two basic body forms Polymorphic- polyp form then medusa stage * Sting cells called nematocysts (Located on tentacles) * Gut with one opening * Reproduce by asexual and sexual methods * Nerve Network (No brain) * Carnivorous * Aquatic (Mostly marine) * Radial symmetry

Phylum: Platyhelminthes
Example- Tape Worm, Planarian * Flattened body shape * Bilateral symmetry * Mouth but no anus * Many are parasitic but otherwise free living * Marine, freshwater, damp water * Digestive system with a single opening * No organs for gas exchange * Hermaphroditic * Dorso ventrally flattened

Phylum: Nematoda
Example. Stomach Worms, Lung Worms * Tiny unsegmented worms * Free living or parasitic * Aquatic marine or freshwater, damp terrestrial * Cylindrical body with tapered ends * Digestive system with mouth and anus

Phylum: Annelida
Example. Leech, Marine worms * Aquatic or damp terrestrial * Bilateral symmetry * Internally and externally segmented bodies * Mostly hermaphrodites * Mouth and anus * Circulatory system and nervous system (well developed)

Phylum: Mollusca
Example. Snails, Squid, octopus, squid * Cephalisation- Head development * Muscular foot for locomotion * Soft bodied, unsegmented * Organs * Digestive system with mouth and anus – feed with radula (Rasping tongues) * Aquatic and terrestrial species * Aquatic species posses gills * 3 GROUPS. * Bivalves – clams, scallops, pippis * Gastropods- Snails,…