ch. 28 biodiversity

BIODIVERSITY

CLASSIFICATION

Organisms are divided into different categories 

Increasing similarities down the group 

1. Kingdom → fundamental features 

2. Phylum → more common features 

3. Class

4. Order

5. Family 

6. Genus 

7. Species 

Organisms = species potentially capable of interbreeding to produce fertile offspring

Usually defined as organisms with similar structure features and genetic materials 

Species name : e.g. Taraxacum officinale  

Taraxacum = genus name (start with a capital letter)

Officinale = species name (start with lowercase letter)

Written → underlined 

Types → italics 

1. Kingdom eubacteria 

 Refers to bacteria, very small 

Can only be observed under light microscopes with high power \

Major Features 

• Unicellular prokaryotes, they have no true nucleus

• Genetic material is circular DNA → referred as the bacterial chromosome 

• Have no membrane-bound organelles 

• Respiration and photosynthesis may take place at specific areas of the cell membrane 

• Have a cell wall which is made of peptidoglycan → some are enclosed by a capsule and some have hair-like flagellum 

2. Kingdom archaebacteria 

Are unicellular prokaryotes → some are even smaller than bacteria 

They are more closely related to eukaryotes than to bacteria 

Major feature 

• Most have cell walls but their chemical composition is unique 

• The lipid that makes up the cell membrane is different from other organisms 

• Many can live in extreme environment 

→ e.g. hot and acidic environment, very salty environment, environment lacking oxygen 

3. Kingdom Protista 

The organisms in this kingdom are called protists 

Major feature 

• They are eukaryotes and most are unicellular 

• Have true nucleus and other membrane-bound organelles 

• They live mainly in water or inside other organisms 

3 main types of protists 

1. Protozoans 

They are animal-like → can move from place to place 

E.g. amoeba, paramecium

2. Algae 

Plant, have chloroplasts and make their own food through photosynthesis 

E.g. diatoms and dinoflagellates are unicellular algae

3. Slime mould 

In their feeding stage → exist as unicellular (amoeba-liked cells)

In the reproductive stage → they look like fungi

      D. Kingdom Fungi 

Major feature 

• Most are multicellular, they are made up of thread-like hyphae, which may interweave to form a mycelium

• Some may form a specialized fruiting body that releases spores for reproduction 

• They have cell walls, but they are not made of cellulose 

• They have no chlorophyll so they can't produce food 

Have different types 

1. Most carry saprophytic nutrition → feed on dead organisms or non-living organic matter 

E.g. mushroom or bread mould  

2. Some carry out parasitic nutrition → obtain food from their living host 

E.g. athletes foot 

1. Some are unicellular eg. yeast

      E.  kingdom Plantae 

• They are autotrophs → have chlorophyll for photosynthesis 

• Have a cell wall composed of cellulose 

• Plants do not move from place to place 

• They can be divided into vascular plants and non-vascular plants 

Plants → non-vascular plant or vascular plants 

Vascular plants → ferns or conifers or flowering plants 

Flowering plants → monocotyledonous plants or dicotyledonous plans 

1. Non-vascular plants

• They have no vascular tissues → have simple stems and leaves but no true roots 

• Most of them grow in shady and damp places 

• They have rhizoids for anchorage and for absorption of water and minerals 

• Have chlorophyll for photosynthesis

• Produce spores for reproduction 

2. Vascular plants 

• Have vascular tissues and have true roots stems and leaves 

• Most live in dry places 

• Divided into 3 main groups → ferns (not producing seeds), conifers (produce seeds but not flowers), flowering plants (produce both seeds and flowers) 

• Vascular tissues → xylem: transport water, phloem: transport food 

• Ferns 

• Ferns have large and feathery leaves 

• Do not produce seeds → produce spores for reproduction 

• Spores are located on the underside of the leaves 

• conifers

• Are trees or shrubs bearing cones

• Cones carry seeds for reproduction 

• Seeds are called naked seeds → they are not enclosed in fruits 

• Most have needle-shaped leaves

• Flowering plants 

• Plants produce flowers for reproduction → seeds are formed are protected inside fruits 

• Divided into monocotyledonous plants and dicotyledonous plants  → abbreviated into monocots and dicots 

•  

       F. kingdom Animalia 

• Are heterotrophs → they obtain food from other organisms 

• Do not have a cell wall 

• Can move freely 

• Divided into vertebrates and invertebrates

• Vertebrates → have backbone along their back 

• Invertebrates → do not have 

Vertebrates → 1. Fish 2. Amphibians 3. Reptiles 4. Birds 5. Mammals 

1. Invertebrates → without a backbone 

→ Hollow-bodied animals 

• Have tentacles with stinging cells for catching small prey 

• They have only one body opening which serves as both the mouth and anus 

E.g. jellyfish, corals 

→ Segmented worms 

• They have tube-like bodies with a lot of segments 

• They have chaetae for movement 

E.g. earthworm, sandworm 

→ Soft-bodied animals 

• They have a soft body 

• Have muscular foot for movement 

• Some are protected by a hard shell

E.g. snails, clams 

→ Joint-legged animals 

• Makeup about 75% of all animals 

• Their body is segmented and covered by the exoskeleton 

• Have three or four pairs of jointed legs 

• May have antenna, mouth parts, wings and compound eyes 

E.g. insects, crustaceans 

→ Spiny-skinned animals 

• Have spines on the body surface

• They have numerous tube feet for movement 

E,g, sea urchins, sea cucumbers 

2. Vertebrates

→ fish 

• Body features

They have gills for gas exchange 

Have fins for balance and movement 

Have slimy scales 

• Method of reproduction 

Carry out external fertilization  

Most lay eggs in water 

• Control of body temperature

They are poikilotherms → Body temperature varies with external temperature

→ amphibians 

• Body features 

Use lungs and the surface of the skin to carry out gas exchange 

Their larvae (tadpoles) use gills for gas exchange 

Most have four limbs 

Are covered with moist naked skin 

• Method of reproduction 

They carry out external fertilization 

Lay eggs in water 

• Control of body temperature

Poikilotherms 

E.g. frogs, toads, salamanders 

→ reptiles 

• Body features 

Have lungs ofr gas exchange 

Have dry, hard scales 

Have four limbs 

• Method of reproduction 

Internal fertilization 

Most reptiles lay eggs with soft shells 

• Control of body temperature 

Poikilotherms 

E.g. crocodiles, lizards 

→ birds 

• Body features 

Lungs for gas exchange

Wings 

Feathers 

Dry scale on their feet 

Beak and no teeth 

• Method of reproduction

Internal fertilization

Lay eggs with hard shell 

• Body temperature 

Homoiotherms 

E.g. sparrows, ducks 

→ mammals 

• Body features 

Have  lungs for gas exchange

Have hair 

Have pinnae 

Have mammary glands 

• Metod of reproduction 

Carry out internal fertilization 

Give birth to live young 

• Body temperature 

Homoiotherms 

E.g. humans, cow