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Flashcards in Classification and evolution Deck (34)
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1

Need for a classification system

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

2

Linnean classification

Hierarchy based on taxonomic groups:
domain, kingdom, phylum, class, order, family, genus, species

3

Mnemonic of taxonomic groups

King
Philip
Came
Over
From
Great
Spain

4

Species definition

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

5

Handwritten version of a scientific name

underlined + genus starts with uppercase

6

The five kingdoms

Prokaryotes (bacteria)
Protoctista
Fungi
Plantae
Animalia

7

Prokaryotes features
(eg: E. coli)

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

8

Protoctista features
(eg: Paramecium and Amoeba)

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)

9

Fungi features
(eg: mushrooms, moulds, yeast)

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

10

Plantae features
(eg: flowering plants, trees, grass)

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

11

Animalia features
(eg: humans, reptiles, mammals, sponges etc)

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

12

Domains

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.

13

Eukarya characteristics

80s ribosomes
RNA polymerase contains 12 proteins

14

Archae characteristics

70s ribosomes
RNA polymerase contains 8-10 proteins

15

Bacteria characteristics

70s ribosomes
RNA polymerase contains 5 proteins

16

Woese's 6 kingdoms

Eubacteria
Archae-bacteria
Protoctista
Fungi
Plantae
Animalia

17

Phylogeny

Evolutionary relationships between organisms

18

Phylogenetics

Study of evolutionary history of groups of organisms

19

Advantages of phylogeny over Linnean classification

--> 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)

20

Evidence for evolution

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

21

Homologous structure

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

22

Molecules studied for comparative biochemistry

Cytochrome c (involved in respiration) and ribosomal RNA

23

Types of variation (based on what it affects)

Interspecific (between 2 or more different species)
Intraspecific (between organisms of the same species)

24

Causes of variation

- 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

25

Types of variation (based on type of data collected)

Continuous (height, weight) - polygenic and environmental
Discontinuos (shape of microorganisms, human blood groups) - monogenic

26

Student's t test

Used to compare means of data values of 2 populations

27

Spearman's rank correlation coefficient

Analysing the relationship between 2 sets of data

28

Types of adaptations

Anatomical
Behavioural
Physiological

29

Anatomical adaptations

body covering
camouflage
teeth
mimicry

30

Behavioural adaptations

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