1.3. Features of organisms

 

The largest group of classification is Kingdom. There are 5 kingdoms and they are: Animal, Plant, Fungus, Prokaryote and Protoctist.

Cells of all living organisms contain:

• cytoplasm, cell membrane and DNA as genetic material
• ribosomes - for protein synthesis
• enzymes - involved in respiration

Here are all the groups of living things we will need to know! 

Attn!: Viruses are NOT true living things!

The main differences in the 5 kingdoms are:

[for more information on the kingdoms, please click here]

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1. Kingdom: Animal

Please follow these links for more details on Phylum Vertebrates and Phylum Arthropods.

[There are other groups of invertebrates (Annelids, Nematodes and Molluscs) which don't seem to be listed on the 2022 syllabus, but if you're interested, please click here]

2. Kingdom: Plant

The 2 main groups we'll focus on within this kingdom are flowering plants and ferns.

A) Flowering plants

• multicellular, with cellulose cell walls and sap vacuoles
• roots, stems, leaves
• sexual reproduction via seeds; asexual reproduction possible
• 2 groups: monocotyledons and dicotyledons 

[for more on plants, click here]

B) Ferns

• 
  roots stems, leaves
• stems below ground called rhizome
• stems and leaves have sieve tubes and water-conducting cells
• NO buds! young leaves unwind from tight coils
• reproduction:
• produce gametes, but NO seeds
• gametes --> zygote --> fern plant
• fern plant have sporangia (spore capsules) that produce single-celled spores on the lower side of the leaves

3. Kingdom: Fungus

[The syllabus doesn't really specify much for fungi, but if you're interested, check 'em out with this link]

4. Kingdom: Prokaryotes (bacteria)

[The syllabus doesn't really specify much for prokaryotes either, but feel free to check 'em out with this link]

5. Kingdom: Protoctist

The syllabus ain't showing much love for these guys either :( There's also nothing to click, which is OK because you're probably tired of clicking by now, so here are some diagrams to look at :)

Viruses

Viruses are their own peculiar breed and are NOT true living things!

   

Key features:

• very small (100 times smaller than bacteria)
• no typical cell structure
• contain a strand of DNA or RNA
• surrounded by a protein coat called a capsid
• only sign of life is reproduction (in host cells)

[more on viruses: click here for the o.g. post]

For more past paper questions, click here.

Phew! This was a real long section but look! you've made it to the end so congrats :)