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IB Biology > 5. Evolution > Flashcards

5. Evolution Flashcards

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1
Q

Bryophytes

A 
No xylem or phloem
No leaves, roots or stems
Reproduces via spores 
Anchored by rhizoids 
Ex: Mosses
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2
Q

Filicinophyta

A 
Has xylem and phloem 
Has leaves, roots or stems
Reproduces via spores
Leaves are pinnate
Ex: Ferns
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3
Q

Coniferophyta

A 
Has xylem and phloem
Has leaves, roots or stems
Reproduces via seeds in cones
Has woody stems
Ex: pine trees
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4
Q

Angiospermopyta

A 
Has xylem and phloem
Has leaves, roots or stems
Reproduces via seeds in fruits
Has flowers and fruits
Ex: Flowers
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5
Q

Definition of Evolution

A

The cumulative change in the heritable characteristics of a population over time

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6
Q

What are fossil records and what do they show

A

The totality of fossils- both discovered and undiscovered.

Provides evidence for evolution - shows a gradual change of species over time

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7
Q

Law of fossil succession

A
  • Fossils can be dated by determining the age of the rock layer (strata) in which the fossil is found
    • Sedimentary rock layers develop in chronological order
      • Fossils show a chronological time sequence in which characteristics appear and develop in complexity
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8
Q

Transitional fossils- what do they show, what are they evidence for

A
  • Show links between species by exhibiting traits common to both ancestral species and its descendant species
    • Ex: archaeopteryx - dinosaurs and birds
      • Evidence for macroevolution- development of new species
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9
Q

Selective Breeding- what is it and what does it show for evolution

A

When humans intervene to breed individuals with the most desirable traits

- Trait's frequency becomes more common in successive generations 
- Evidence for evolution: targeted breeds show significant variation in a short period of time 
- Accelerates evolutionary process
- Evidence for microevolution- changes within a species 
    - Shows that artificial selection can cause evolution
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10
Q

Homologous structures

  • Definition
  • Example
  • Evidence for?
A
  • Homologous Structures are similar shape in different types of organisms but have different functions
  • Ex: Pentadactyl limb in vertebrates : same structure but adapted to different mode of locomotion in certain environment
  • Evidence for adaptive radiation and divergent evolution
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11
Q

Define Divergent Evolution

A

When two separate species have a similar structure but use it in different ways because of their environment

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12
Q

Define Adaptive Radiation

A

Form of divergent evolution where many species evolve from a common ancestor to occupy a range of available niches

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13
Q

Analogous structures

  • Definition
  • Example
  • Evidence for?
A
  • Anatomical features performing a similar function but having a different evolutionary origin
  • Ex: wings of insects and birds
  • Evidence for convergent evolution
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14
Q

Define Convergent Evolution

A

Organisms that are not closely related evolve similar structures that are used for similar purposes

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15
Q

Speciation

  • Definition
  • How does it happen
A
  • The evolutionary process by which two related populations diverge into separated species
  • If two populations of a species become geographically separated, they will adapt to different environmental conditions and gradually diverge from one another
  • As genetic divergence increases, genetic compatibility decreases
  • When the two diverged populations meet again and cannot interbreed to produce fertile offspring, speciation has occurred
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16
Q

Explain industrial melanism example

A

Peppered moths- exist in two morphs/variations: light and dark form
- In an unpolluted environment, trees covered in lichen allowed light coloured moths to camouflage
- In a polluted environment (following industrial revolution), sulphur dioxide kills lichen and soot darkens bark, providing camouflage for dark coloured moths
- Frequency of the allele depends on the environment and evolves as conditions change
- Prior industrial revolution, light coloured moths had survival advantage, after industrial revolution, dark coloured moths did
- Pollution as natural selection pressure
Peppered moth would slowly diverge into two different species

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17
Q

Continuous variation

A

Type of variation controlled by many genes, has a wide range of variability and can be influenced by environment

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18
Q

Discontinuous variation

A

Type of variation that is influenced by genes, can be categorised, and is not influenced by environment

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19
Q

Steps of Natural Selection

A
  1. Genetic variation inherited
  2. Competition due to overpopulation for survival
  3. Adaptations- ‘survival of the fittest’
  4. Selection- successful inheritance of successful variations –> change in allele frequency –> evolution
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20
Q

Causes of variation

A
  • Mutation - change in DNA base sequence
  • Meiosis - crossing over and independent assortment
  • Sexual reproduction - random fertilization
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21
Q

Types of adaptations

A

Structural i.e. neck length
Behavioral i.e. nocturnal
Physiological i.e. colour perception
Biochemical i.e. blood group

22
Q

How do adaptations contribute to natural selection (in more detail)

A

Adaptations are characteristics that make an individual suited to its environment and way of life

    - Individuals that are better adapted tend to survive and reproduce more offspring while the less adapted tend to die and produce fewer offspring 
    - leads to changes in the gene pool
23
Q

How do natural selection pressures lead to speciation

A

Natural selection pressures –> adaptive radiation (from adaptations) –> divergent evolution –> speciation

24
Q

Galapagos finches example

A
  • Changes in beaks of flinches on the Galapagos islands
    ○ Specialised beak shapes depending on primary source of nutrition
    • Illustrates adaptive radiation
      ○ Members evolve different adaptations in response to the different selection pressures
    • Dry conditions –> larger seeds –> finches with larger beaks survive and reproduce –> allele frequency increases as offspring inherit large beak allele
25
Q

Antibiotic Resistance example

A
  • Bacteria reproduces and some can mutate- some of which causes resistance
    • Resistant bacteria survives antibiotic treatment and reproduces by binary fission
    • Resistant bacteria reproduce rapidly as competition eliminated by antibiotics
    • Resistance bacteria develops and spreads easily with people
    • Resistance can come from plasmid transfer of resistance-carrying genes
      • Antibiotic (selection pressure) increases the antibiotic resistance gene frequency, bacteria susceptible to antibiotic dies –> evolution
26
Q

Key words in example answer (natural selection)

A
  • overproduction
  • variation
  • mutation (if relevant)
  • environmental change/pressure
  • survival of the fittest
  • adaptation
  • ‘passed onto offspring’
  • change in gene pool
27
Q

The binomial system

A
  • The formal system by which all living species are classified (taxonomy)
    - Universally agreed and developed by a series of congresses
28
Q

Hierarchy of Taxa

A
  • Kingdom
    • Phylum
    • Class
    • Order
    • Family
    • Genus
      • Species
29
Q

3 Domains + differences

A

Bacteria- naked DNA, peptidoglycan cell wall
Archaea- Histones (in some), no peptidoglycan cell wall
Eukaryota- Histones, sometimes cell wall present, membrane-bound nucleus, one cell or more

30
Q

4 Kingdoms of Eukaryotes

A
  • Protista
    • Fungi
    • Plantae
      • Animalia
31
Q

What is natural classification

A
  • A genus and accompanying higher taxa consist of all the species that have evolved from one common ancestral species
    - Assumes all members of a particular group would have a shared common ancestor
32
Q

Advantage and Disadvantage of Natural classification

A
  • Advantages
    ○ Identifies traits based on groupings, rather than assigning groups based on traits
    ○ Can be used to predict characteristics shared by species within a group
    ○ Can show be used to show evolutionary relationships
    • Disadvantage
      ○ highly mutable and tend to change as new information is discovered
      ○ taxonomists can reclassify if new evidence shows a different ancestry or a new common ancestry
33
Q

Porifera

A

Asymmetrical

No gut openings (has pores)

No segmentation

Use spicules for support

Sea sponge

34
Q

Cnidaria

A

Radial

Mouth but no anus

No segmentation

Stinging cells

Jellyfish, coral

35
Q

Platyhelmintha

A

Bilateral

Mouth but no anus

None segmentation

Flattened body

Tapeworm

36
Q

Annelida

A

Bilateral

Mouth and anus

Segmented

Use peristalsis for moving

Leech, earthworm

37
Q

Mollusca

A

Bilateral

Mouth and anus

Non-visible segmentation

May have shell made by mantle

Snail, octopus, squid

38
Q

Arthropoda

A

Bilateral

Mouth and anus

Segmented

Exoskeleton (chitin)

Insects, spiders, crustacens

39
Q

Fish

A

Scales

Fins

External

Gills

Ectothermic

Swim bladder

40
Q

Amphibian

A

Moist skin

4 pentadactyl limbs

External

Simple lungs

Ectothermic

Larvae- water
Adult- land

41
Q

Reptile

A

Scales made out of keratin

4 pentadactyl limbs

Internal - soft eggs

Lungs with extensive folding

Ectothermic

No external ears

42
Q

Bird

A

Feathers

4 pentadactyl limbs + wings

Internal - hard eggs

Lungs with bronchial tubes

Endothermic

Wings
Beaks with no teeth

43
Q

Mammal

A

Hair

4 pentadactyl limbs

Internal - live birth

Lungs with alveoli

Endothermic

Feed young with milk from mammary gland

44
Q

Clade - definition

A

A group of organisms that have evolved from a common ancestor

45
Q

Cladistics - definition

A

System of classifying organisms according to shared characteristics, based on ancestry

46
Q

Cladogram - definition

A

(tree) diagram that shows the evolutionary relationship of a group of organisms

47
Q

What is a node and what does it show

A
  • where clades branch off
  • where speciation has occurred; divergent evolution
  • The fewer the number of nodes between two groups the more closely related they are expected to be
48
Q

Where is evidence for a clade obtained from

A
  • the base sequence of a gene or

- the corresponding amino acid sequence of a protein

49
Q

Molecular clock

A
  • Concept of using the mutation rate of biomolecules to deduce the time in prehistory when divergence happened
  • But different genes/proteins may change at different rates, and differ between organisms, or changes may reverse over time
50
Q

What part of the DNA sequence provide most information

A

Non-coding parts of DNA provide the most information as mutations occur more frequently in these regions than coding regions

51
Q

How can structurally similar species be reclassified to be of different families

A

Molecular evidence show that species thought to be closely related based on shared structural characteristics actually have different evolutionary origins

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