AS OCR Biology > Unit 4.3- Classification and evolution > Flashcards

Unit 4.3- Classification and evolution Flashcards

(46 cards)

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1
Q

Binomial system definition:

A

A system that uses the genus name and species name to avoid confusion when naming organisms

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2
Q

What is the order of the modern classification hierarchy

A
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
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3
Q

What are the three domains of the classification hierarchy?

A
  • Archaea
  • Eubacteria
  • Eukaryote
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4
Q

What are the five kingdoms of the classification hierarchy?

A
  • Plantae
  • Animalaia
  • Fungi
  • Protacista
  • Prokaryote
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5
Q

How does does phylum category divide organisms?

A

Splits them into organisms that have the same body plan e.g. possession of a backbone

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6
Q

How does the class category divide organisms?

A

Splits organisms into groups that all posses the same general traits e.g. same number of legs

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7
Q

How does the order category divide organisms?

A

A sub division of class using additional information e.g. carnivores and herbivores

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8
Q

How does the family category divide organisms?

A

Closely related genera e.g. dog family

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9
Q

How does the genus category divide organisms?

A

A group of closely related species

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10
Q

How did Aristotle classify living things?

A

Into plants and animals. He furthered classified animals into those who:

  • Live and move in water
  • Live and move on land
  • Move through the air
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11
Q

How did electron microscopes help with classification?

A

They revealed further details inside cells. Made it clear that many single celled organisms share some features of both plants and animals so do not fit into either kingdom

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12
Q

What are the features of prokaryotae?

A
  • No nucleus
  • Loop of DNA not arranged in linear chromosomes
  • Naked DNA
  • No membrane bound organelles (prokaryotic)
  • Smaller ribosomes than other groups have
  • Smaller cells than eukaryotes have
  • May be free living or parasitic
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13
Q

What are the features of protacista?

A
  • Eukaryotic
  • Mostly single cells, but many algae are multi cellular
  • Show a variety of form (only similarity is that they don’t fit into the other groups)
  • Mostly free-living
  • Have autotrophic or heterotrophic nutrition
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14
Q

What are the features of fungi?

A
  • Eukaryotic
  • Can exist as single cells, or they have a mycelium which consists of hyphae
  • Have walls made of chitin
  • Have a cytoplasm that is multinucleate (more than one nucleus per cell)
  • Mostly free living and saprophytic (cause decay of organic matter)
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15
Q

What are the features of plantae?

A
  • Eukaryotic
  • Multicellular
  • Have cells surrounded by a cellulose cells wall
  • Autotrophic (absorb simple molecules and build them into larger organic molecules)
  • Contain chlorophyll
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16
Q

What are the features of anamalia?

A
  • Eukaryotic
  • Multicellular
  • Heterotrophic (digest large organic molecules into smaller molecules for absoption
  • Usually able to move around
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17
Q

What evidence can be used in classification?

A
  • Cytochrome C

- DNA

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18
Q

What is cytochrome C and how is it used for classification?

A

A protein used in respiration. All living organisms that respire have cytochrome C, but it is not identical in all species. The amino acids that make up cytochrome C can be identified and the more similar the two sequences from two different species are, the more closely related the species are

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19
Q

How is DNA used for classification?

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A

Mutations are changes to the sequence of bases. The more similar a part of the DNA the more closely related two species are. If they are quite different, it suggests the species evolved separately a long time ago so are less closely related.

20
Q

What did Carl Woese base his ideas for the three-domain classification system on?

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A

the ribosomal RNA gene

21
Q

What is the three domain classification system like?

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A
  • Prokaryotes are split into two groups: bacteria (eubacteria) and archaea (archaebacteria)
  • Eukaryotes
22
Q

Why in the three domain classification system are prokaryotes split into two groups?

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A

Bacteria are fundamentally different from Archaea and eukaryotes

23
Q

What are the differences between bacteria and archaea and eukaryotes?

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A

Bacteria have:

  • A different cell membrane structure
  • Flagella with a different internal structure
  • Different enzymes
  • No proteins bound to their genetic material
  • Different mechanisms for DNA replication and for synthesising RNA
24
Q

What features do archaea share with eukaryotes?

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A
  • Similar enzymes for synthesising RNA
  • Similar mechanisms for DNA replication and synthesising RNA
  • Production of some proteins that bind to their DNA
25
Phylogeny definition:
The study of the evolutionary relationships between organisms
26
What is artificial classification?
Classification for convenience - Based on only a few characteristics - Does not reflect any evolutionary relationships - Provides limited information - Is stable
27
What is natural classification?
- Uses many characteristics - Reflects evolutionary relationships - Provides a lot of useful information - May change with advancing knowledge
28
Natural selection definition:
The term used to explain how features of the environment apply a selective force on the reproduction of individuals in a population
29
What are the observations Darwin made?
- Offspring generally appear similar to their parents - No two individuals are identical - Organisms have the ability to produce a large number of offspring - Populations in nature tend to remain fairly stable in size
30
What are the conclusions Darwin made from his observations?
- There is a struggle to survive - Better-adapted individuals survive and pass on their characteristics - Over time, a number of changes may give rise to a new species
31
What evidence is there for evolution?
- Fossil evidence | - Biological molecules
32
Why is mitochondrial DNA useful for tracking human ancestry?
- It does not get confused with the paternal DNA | - There is lots of variation in mDNA from different parts of the world, which allows the movement of people to be traced
33
Continuous variation definition:
Variation where there are two extremes and a full range of values in between
34
Discontinuous variation definition:
Where there are distinct categories and noting in between
35
Environmental variation definition:
Variation caused by response to environmental factors such as light intensity
36
Genetic variation definition:
Variation caused by possessing a different combination of alleles
37
Interspecific variation definition:
The differences between species
38
Intraspecific variation definition:
Variation between different members of the same species
39
Adaptation definition:
A characteristic that enhances survival in the habitat
40
Anatomical adaptations definition:
Structural features enhancing survival chances
41
Behavioural adaptations definition:
The way that behaviour is modified for survival
42
Physiological adaptations definition:
Affect the way processes work e.g. a black bear's heart beat dropping while hibernating
43
What is a well adapted organism able to do?
- Find enough food or photosynthesise well - Find enough water - Gather enough nutrients - Defend itself from predators and diseases - Survive the conditions of its environment - Respond to changes in its environment - Have sufficient energy to allow successful reproduction
44
What are the anatomical adaptations of marram grass?
- Long roots that spread over a wide area and deep underground - Leaves are curled, building up moisture inside and reducing evaporation - Lower epidermis covered in hairs, reducing air movement - Few stomata - Waxy cuticle
45
What are the behavioural adaptation of marram grass?
- Responds to a shortage of water by rolling the leaf more tightly and closing the stomata - When covered by grass, marram grass will grow more quickly to reach the sunlight
46
What are the physiological adaptations of marram grass?
- The ability to roll its leaf is due to the action of specialised hinge cells in the lower epidermis - The guard cells open and close the stomata - Maintains a low water potential lower than other plants, which enables it to live in salty conditions by the sea - Leaves contain many lignified cells that provide support when turgidity is lost, keeping the leaf upright when water is not available
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