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z - A Level Biology > 4.2.2: Classification and evolution > Flashcards

4.2.2: Classification and evolution Flashcards

1
Q

Classification

A

Putting living things into groups with other organisms that share similar characteristics.

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2
Q

Number and names of historic taxonomic groups:

A 
7 groups
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
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3
Q

Current taxonomic groups

A
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
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4
Q

Phylogeny

A

the study of evolutionary relationships between species.

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5
Q

Traditional classification kingdoms

A

Prokaryotae, protoctista, plantae, fungi, animalia

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6
Q

3 domains

A
  • Bacteria
  • Archaea
  • Eukaryotae
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7
Q

Kingdoms of modern classification (x6)

A
  • Eubacteria
  • Archaebacteria
  • Protoctista
  • Plantae
  • Fungi
  • Animalia
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8
Q

Why scientists classify organisms

A
  • To identify species
  • To predict characteristics
  • To find evolutionary links
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9
Q

Eubacteria (kingdom)

A
  • Unicelluar
  • No nucleus (prokaryotic)
  • No membrane-bound organelles
  • Carry out respiration on meso
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10
Q

Eubacteria (kingdom)

A
  • Unicelluar
  • No nucleus (prokaryotic)
  • No membrane-bound organelles
  • Carry out respiration on mesosomes
  • Smaller ribosomes (70s) than other organisms
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11
Q

Mesosome

A

Folding in the cell surface membrane

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12
Q

Archaebacteria (kingdom)

A
  • Unicellular, no nucleus or membrane-bound organelles
  • Virtually unchanged since they evolved –> ancient
  • Can survive in extreme environments e.g. hot thermal vents or acidic/anaerobic conditions
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13
Q

Protoctista (kingdom)

A
  • Eukaryotic
  • Mostly single-celled
  • Mostly free living (don’t live within other organisms)
  • Can be autotrophs or heterotrophs
  • Some have chloroplasts
  • “Dustbin kingdom”
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14
Q

Plantae (kingdom)

A
  • Multicellular eukaryotes
  • Autotrophs (because of photosynthesis)
  • Contain chlorophyll
  • Cellulose cell wall
  • Store glucose as starch
  • Can reproduce sexually or asexually (some)
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15
Q

Fungi (kingdom)

A
  • Heterotrophic eukaryotes
  • Unicellular (yeast) or multicellular (mushrooms)
  • Chitin cell wall
  • Reproduce using spores
  • Saprophytic (secrete enzymes)
  • Store glucose as glycogen
  • No chloroplasts
  • Consist of a mycelium (network of multinucleate hyphae)
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16
Q

Animalia (kingdom)

A
  • Multicellular eukaryotes
  • Heterotrophic
  • No cell wall
  • Fertilised egg develops into blastula
  • Usually able to move
  • Store glucose as glycogen
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17
Q

Chordata

A

Name of phylum; mostly vertebrates

18
Q

Common ancestor

A

Organism from which two organisms evolved.

19
Q

Advantages of phylogenetic classification

A

✔︎ Produces a continuous tree; scientists are not forced to place organisms into categories they don’t properly fit into
✔︎ Linnean classification implies different groups with the same rank are equivalent; in reality some have much longer histories (compare cats, short, and orchids, long,) and are much more diverse (30 cat species, 20,000 orchid species)

20
Q

Natural selection

A

“survival of the fittest”; the best adapted to a given environment survive and reproduce; governed by nature, takes millions of years.

21
Q

Artificial selection

A

breeding animals specifically for certain characteristics; governed by humans and takes centuries.

22
Q

Convergent evolution

A

some features are so useful that they will develop independently of one another.

23
Q

Reasons for gaps in the fossil record

A
  • Fossils can be destroyed
  • Fossils may not have been discovered
  • Fossils are only formed under certain conditions
  • Soft bodied organisms may decay before fossils can form
24
Q

Why are fossils useful?

A
  • Shows how organisms have changed over time (different layer of rock corresponds to different geological era)
  • Shows relationships between extinct and extant organisms
25
Q

Comparative anatomy

A

• Gives evidence for divergent evolution

⟶ Common ancestor from which different species have evolved, occurs when organisms have adapted to new habitats

26
Q

How evolution works (Model answer)

A

1) VARIATION caused by genetic MUTATION
2) Environmental selection of advantageous variations (SELECTION PRESSURE)
3) SURVIVAL OF THE FITTEST
4) Reproduction to pass on advantageous characteristics in the form of ALLELES
5) ADAPTATION: next generation better suited to their environment.

27
Q

Methods by which bacteria become resistant to antibiotics

A
  • Build protein that forms efflux pump
  • Code for antibiotic degrading enzyme
  • Code for antibiotic-altering enzyme
28
Q

Types of variation

A
  • Interspecific (between species)

* Intraspecific (within a species)

29
Q

Reasons for increased antibiotic resistance

A
  • Failure to finish a course of antibiotics

* Overuse or incorrect use of antibiotics

30
Q

Two possible causes of variation

A
  • Genotype (genetic causes)

* Environmental factors

31
Q

Environmental causes of variation (examples)

A
  • Plant height (depends on nutrients/light)
  • Hydrangea colour (dependent on pH of soil)
  • Human scars (although how the wound heals may be partially genetically determined)
32
Q

Genetic causes of variation

A
  • Different alleles
  • Mutations (change in DNA sequence alters alleles)
  • Meiosis (independent assortment m1, crossing over p1, random orientation m2)
  • Sexual reproduction (random selection of gametes, combination of alleles from 2 parents)
33
Q

Genetic causes of variation (examples)

A
  • Natural eye colour

* Blood type

34
Q

Variation determined by environmental and genetic factors (examples)

A
  • Human height (max. potential = genetic, malnourishment may reduce)
  • Skin colour (alleles + sun exposure)
35
Q

Continuous variation

A
  • No distinct categories
  • Tends to be quantitative
  • Controlled by genetic factors
  • Influenced by environment
36
Q

Discontinuous/discreet variation

A
  • Distinct categories
  • Tends to be qualitative
  • Controlled by a few genes
  • Unaffected by the environment
37
Q

Polygenic inheritance

A

inheritance of a characteristic controlled by many genes which are often located on different chromosomes.

38
Q

Example of polygenic inheritance

A

Skin tone; controlled by 8 genes

39
Q

Standard deviation shows

A

How much variation there is between the data and the mean. A measure of the spread of the data.

40
Q

Spearman’s rank correlation coefficient

A

Determines the strength of a correlation between two variables.

z - A Level Biology (25 decks)

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