Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

IB Biology > 5. Evolution > Flashcards

5. Evolution Flashcards

(51 cards)

Start Studying
1
Q

Bryophytes

A 
No xylem or phloem
No leaves, roots or stems
Reproduces via spores 
Anchored by rhizoids 
Ex: Mosses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Filicinophyta

A 
Has xylem and phloem 
Has leaves, roots or stems
Reproduces via spores
Leaves are pinnate
Ex: Ferns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Coniferophyta

A 
Has xylem and phloem
Has leaves, roots or stems
Reproduces via seeds in cones
Has woody stems
Ex: pine trees
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Angiospermopyta

A 
Has xylem and phloem
Has leaves, roots or stems
Reproduces via seeds in fruits
Has flowers and fruits
Ex: Flowers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Definition of Evolution

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define Divergent Evolution

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define Convergent Evolution

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Continuous variation

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Discontinuous variation

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Causes of variation

A
  • Mutation - change in DNA base sequence
  • Meiosis - crossing over and independent assortment
  • Sexual reproduction - random fertilization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Types of adaptations

Study These Flashcards
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)

Study These Flashcards
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

Study These Flashcards
A

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

24
Q

Galapagos finches example

Study These Flashcards
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
Antibiotic Resistance example
- 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
Key words in example answer (natural selection)
- overproduction - variation - mutation (if relevant) - environmental change/pressure - survival of the fittest - adaptation - 'passed onto offspring' - change in gene pool
27
The binomial system
- The formal system by which all living species are classified (taxonomy) - Universally agreed and developed by a series of congresses
28
Hierarchy of Taxa
- Kingdom - Phylum - Class - Order - Family - Genus - Species
29
3 Domains + differences
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
4 Kingdoms of Eukaryotes
- Protista - Fungi - Plantae - Animalia
31
What is natural classification
- 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
Advantage and Disadvantage of Natural classification
- 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
Porifera
Asymmetrical No gut openings (has pores) No segmentation Use spicules for support Sea sponge
34
Cnidaria
Radial Mouth but no anus No segmentation Stinging cells Jellyfish, coral
35
Platyhelmintha
Bilateral Mouth but no anus None segmentation Flattened body Tapeworm
36
Annelida
Bilateral Mouth and anus Segmented Use peristalsis for moving Leech, earthworm
37
Mollusca
Bilateral Mouth and anus Non-visible segmentation May have shell made by mantle Snail, octopus, squid
38
Arthropoda
Bilateral Mouth and anus Segmented Exoskeleton (chitin) Insects, spiders, crustacens
39
Fish
Scales Fins External Gills Ectothermic Swim bladder
40
Amphibian
Moist skin 4 pentadactyl limbs External Simple lungs Ectothermic Larvae- water Adult- land
41
Reptile
Scales made out of keratin 4 pentadactyl limbs Internal - soft eggs Lungs with extensive folding Ectothermic No external ears
42
Bird
Feathers 4 pentadactyl limbs + wings Internal - hard eggs Lungs with bronchial tubes Endothermic Wings Beaks with no teeth
43
Mammal
Hair 4 pentadactyl limbs Internal - live birth Lungs with alveoli Endothermic Feed young with milk from mammary gland
44
Clade - definition
A group of organisms that have evolved from a common ancestor
45
Cladistics - definition
System of classifying organisms according to shared characteristics, based on ancestry
46
Cladogram - definition
(tree) diagram that shows the evolutionary relationship of a group of organisms
47
What is a node and what does it show
- 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
Where is evidence for a clade obtained from
- the base sequence of a gene or | - the corresponding amino acid sequence of a protein
49
Molecular clock
- 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
What part of the DNA sequence provide most information
Non-coding parts of DNA provide the most information as mutations occur more frequently in these regions than coding regions
51
How can structurally similar species be reclassified to be of different families
Molecular evidence show that species thought to be closely related based on shared structural characteristics actually have different evolutionary origins

IB Biology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions