Classification and evolution

Question 1

Why do scientists classify organisms

Answer 1

• To identify species: by using a clearly defined system of classification, the species an organism belongs to can be easily identified
• To predict characteristics: if several members in a group have a specific characteristic, it is likely that another species in the group will have the same characteristic
• To find evolutionary links: species in the same group probably share characteristics because they have evolved from a common ancestor

Question 2

What is binominal nomenclature

Answer 2

All species are given a scientific name consisting two parts:

• The first word indicates the organism’s genus. It’s called the generic name.
• The second word indicates the organism’s species. It’s called the specific name.
• No two species have the same generic and specific name. Two different species could have the same specific name, however their genus would be different.

Question 3

What are the advantages of binominal nomenclature?

Answer 3

• Provide extra information
• It is universal
• It breaks language barrier for communication
• Lesser error in communication regarding the studies on any organism because the name is unique to it and samer all around the world

Question 4

What are the five kingdoms

Answer 4

• Prokaryotae (bacteria)
• Protoctista (the unicellular eukaryotes)
• Fungi (e.g. yeast, moulds and mushrooms)
• Plantae (plants)
• Animalia (animals

Question 5

Describe what prokaryotae are

Answer 5

• Unicellular
• No nucleus or other membrane-bound organelles – a ring of ‘naked’ DNA – small ribosomes
• No visible feeding mechanism – nutrients are absorbed through the cell wall or produced internally by photosynthesis

Question 6

Describe what protoctista are

Answer 6

• mainly) unicellular
• a nucleus and other membrane-bound organelles
• some have chloroplasts
• some are sessile, but others move by cilia, flagella or by amoeboid mechanisms
• nutrients are acquired by photosynthesis (autotrophic feeders), ingestion of other organisms (heterotrophic feeders, or both – some are parasitic

Question 7

Describe what fungi are?

Answer 7

• unicellular or multicellular
• a nucleus and other membrane-bound organelles and a cell wall mainly composed of chitin
• no chloroplasts or chlorophyll
• no mechanisms or locomotion
• most have a body or mycelium made of threads or hyphae
• nutrients are acquired by absorption – mainly from decaying material – they are saprotrophic feeders – some are parasitic
• most store their food as glycogen

Question 8

Describe what plantae are?

Answer 8

• multicellular
• a nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose
• all contain chlorophyll
• most do not move, although gametes of some plants move using cilia or flagella
• nutrients are acquired by photosynthesis – they are autotrophic feeders – organisms that make their own food
• store food as starch

Question 9

Describe what animalia are?

Answer 9

• multicellular
• a nucleus and other membrane-bound organelles (no cell walls)
• no chloroplasts
• move with the aid of cilia, flagella, or contractile proteins, sometimes in the form of muscular organs
• nutrients are acquired by ingestion – they are heterotrophic feeders
• food stored as glycogen