Kingdoms, Phylums and Class

Prokaryote

• Unicelluar
• Cell wall made from muerin
• No membranous organelles inc nucleus
• Circular DNA

Protoctista

• Complex unicellular,  with membranous organelles. 

Fungi

• Multicellular
• Network of threads (hyphae) forming Mycelium 
• Cell wall made from chitin
• Reproduction by spores without flagella
• Some hyphae have 'cross walls' or septa

Plants

• Multicellular
• Autotrophic with chloroplasts with photosynthetic pigment
• Cell wall made from cellulose
• Vacuoles with cell sap

Animalia

• Multicellular
• No cell wall
• Nervous coordination
• Heterotrophic

Annelida

• Long thin segmented body
• Fluid filled haemocoel
• Close circulatory system with pigment
• Thin skin with good blood supply
• Primitive brain
• Hydrostatic skeleton

6 POINTS TO REMEMBER

Arthropoda

• Segmented body
• Paired jointed legs
• Thick exoskeleton made from chitin
• Open circulatory system and cavity that surrounds organs
• Well developed brain

5 POINTS

Exoskeleton:

• doesnt grow so must be shed (ecdysis), leaving organism vulnerable

• Reduces water loss
• Place for muscles to join
• Better support for smaller insects
• protection from predators

Chordata

• Well developed brain (in a cranium) and nervous system
• Rod or backbone
• Closed circulatory system

Fish-

• Aquatic
• Scales and gills
• External fertilisation

Amphibians-

• Terrestrial and aquatic
• Moist thin skin and primitive lungs for gaseous exchange
• Young are aquatic with gills
• External fertilisation

Reptiles

• Terrestrial- dry scales impermeable
• Lungs
• Internal fertilisation, laid eggs with leathery shell
• Trunk of body above ground

Birds

• Similar to above,  with feathers and wings
• hard shells

Mammals

• Skin with hair
• Lungs
• Internal fertilisation-live young birth and fed milk

Marsupials- born very young and develop further in pouch feeding off milk.

Placentals- remain in womb until very developed, given nutrition by the placenta.

They have hair, live young who are fed with milk. They have developed lungs, brain and nervous function. 

Theory of evolution suggests all organisms have a common ancestor, and therefore, many should show similar structural features.

Homologous features are said to have the same structure, although may have a very different function. An example is the pentadactyl limb in 4 classes of chordata (not fish.)

The pentadactyl limb has very different functions for different animals.

The whale have it as a fin, bats as a wing and humans as a hand. The more simiilar the structure of the limb, the more recently the organisms diverged in evolutionary history.

However, analogous features offer a risk, as they look the same, and have the same function but with very different structural origins.

convergent evolution results in analogous features

divergent evolution results in homologous features

DNA hybridisation- extract and compare bases in DNA between two organisms and the more similar they are  the closer they are related. 

immunological testing- when the antigens of onr species reacts with antibodies a precipitate is formed. the more precipitate the closer related.

protein sequencing- comparing protein sequence in the same protein of two different organisms. The less differences in proteins,  the closer the relation. 

DNA analysis- dna is extracted, cut up then mixed. this shows that chimpanzees and humans have 97.6% rhesus and humans have 91.1%

They have the following 4 features that are unique to their class:

• 6 paired legs
• pair of antennae and compound eyes
• gaseous exchange through gills or tracheae.
• Many have wings

Some of these features have been secondarily lost e.g. no wings in fleas or lice.