Classification and evolution

Question 1

Need for a classification system

Answer 1

• To identify species
• To find evolutionary links
• To predict characteristics
• Scientists around the world can share their research

Question 2

Linnean classification

Answer 2

Hierarchy based on taxonomic groups:

domain, kingdom, phylum, class, order, family, genus, species

Question 3

Mnemonic of taxonomic groups

Answer 3

King
Philip
Came
Over
From 
Great
Spain

Question 4

Species definition

Answer 4

A species is the smallest taxonomic group that consists of organisms that are able to reproduce to produce fertile offspring.

Question 5

Handwritten version of a scientific name

Answer 5

underlined + genus starts with uppercase

Question 6

The five kingdoms

Answer 6

Prokaryotes (bacteria)
Protoctista
Fungi
Plantae
Animalia

Question 7

Prokaryotes features

eg: E. coli

Answer 7

Type of organism: unicellular
Genetic material: ring/circular naked DNA
Feeding mechanism: not visible, absorbed through cell wall or produced by photosynthesis

Question 8

Protoctista features

eg: Paramecium and Amoeba

Answer 8

Type of organism: unicellular
Organelles: nucleus, membrane-bound organelles, chloroplasts
Movement: sessile/ by cilia, flagella, amoeboid mechanism
Feeding mechanism: autotrophic (photosynthesis), heterotrophic (ingestion of other organisms), or parasitic (both)

Question 9

Fungi features

eg: mushrooms, moulds, yeast

Answer 9

Type of organism: unicellular or multicellular
Organelles: nucleus, membrane-bound organelles, cell wall made of chitin
No movement
Body/mycelium made of shreds/hyphae
Feeding mechanism: saprophytic (absorption of nutrients) and parasitic - food stored as glycogen

Question 10

Plantae features

eg: flowering plants, trees, grass

Answer 10

Type of organism: multicellular
Organelles: nucleus, membrane-bound organelles (eg chloroplasts with chlorophyll), cell wall made of cellulose
Movement: most do not move, however gametes of plants move with the aid of cilia or flagella.
Feeding mechanism: autotrophic (photosynthesis) - food stored as starch

Question 11

Animalia features

eg: humans, reptiles, mammals, sponges etc

Answer 11

Type of organism: multicellular
Organelles: nucleus, membrane-bound organelles (no cell wall)
Movement: cilia, flagella, contractile proteins, muscular organs
Feedings mechanism: heterotrophic (ingestion) - food stored as glycogen

Question 12

Domains

Answer 12

Eukarya, Archae, Bacteria
Discovered by Carl Woese
Classification based on differences in sequences of nucleotides in cells’ rRNA, cells’ membrane lipid structure, and sensitivity to antibiotics.

Question 13

Eukarya characteristics

Answer 13

80s ribosomes

RNA polymerase contains 12 proteins

Question 14

Archae characteristics

Answer 14

70s ribosomes

RNA polymerase contains 8-10 proteins

Question 15

Bacteria characteristics

Answer 15

70s ribosomes

RNA polymerase contains 5 proteins

Question 16

Woese’s 6 kingdoms

Answer 16

Eubacteria
Archae-bacteria
Protoctista
Fungi
Plantae
Animalia

Question 17

Phylogeny

Answer 17

Evolutionary relationships between organisms

Question 18

Phylogenetics

Answer 18

Study of evolutionary history of groups of organisms

Question 19

Advantages of phylogeny over Linnean classification

Answer 19

• -> Phylogeny produces a continuous tree, while classification requires discrete taxonomic groups.
• -> Linnean classification has a hierarchal nature which can be misleading as it can suggest that different groups in the same rank are equivalent (eg cats and orchids)

Question 20

Evidence for evolution

Answer 20

1. Paleontology (study of fossils and fossil records)
2. Comparative anatomy
3. Comparative biochemistry

Question 21

Homologous structure

Answer 21

Structures that appear superficially different, but have the same underlying structure. This provides evidence for divergent evolution (result of migration or loss of habitat)

Question 22

Molecules studied for comparative biochemistry

Answer 22

Cytochrome c (involved in respiration) and ribosomal RNA

Question 23

Types of variation (based on what it affects)

Answer 23

Interspecific (between 2 or more different species)

Intraspecific (between organisms of the same species)

Question 24

Causes of variation

Answer 24

• Alleles
• Mutations (either in somatic cells - only individual is affected, or in gametes - mutation is inherited)
• Meiosis (independent assortment and crossing over)
• Random fertilisation due to chance

Question 25

Types of variation (based on type of data collected)

Answer 25

Continuous (height, weight) - polygenic and environmental

Discontinuos (shape of microorganisms, human blood groups) - monogenic

Question 26

Student’s t test

Answer 26

Used to compare means of data values of 2 populations

Question 27

Spearman’s rank correlation coefficient

Answer 27

Analysing the relationship between 2 sets of data

Question 28

Types of adaptations

Answer 28

Anatomical
Behavioural
Physiological

Question 29

Anatomical adaptations

Answer 29

body covering
camouflage
teeth
mimicry

Question 30

Behavioural adaptations

Answer 30

courtship 
survival behaviours (eg playing dead)
seasonal behaviours (eg migration, hibernation)

Question 31

Types of behavioural characteristics

Answer 31

Innate (inherited through genes)

Learned (learnt from experience)

Question 32

Physiological characteristics

Answer 32

poison production
antibiotic production
water retention

Question 33

Analogous structures

Answer 33

Unrelated species that have different genetic origins, but have adapted to perform the same function. Evidence for convergent evolution (due to adapting to similar environments/selection pressures)

Question 34

Selection pressure

Answer 34

Factors that affect an organism’s chances of survival or reproductive success