Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology HL > Evolution CHAP 5 > Flashcards

Evolution CHAP 5 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is the definition of Evolution?

A

The cumulative change in the heritable characteristics of a population

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

Evolution: The Characteristics are encoded by ___ and transferred between generations as ______

A

1) Genes 2) Alleles

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

_____ is a change in the allele frequency of a populations gene pool over successive generations

A

Evolution

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

Evolutionary changes affect variation and diversification within a population via 6 main mechanisms.

Which are?

A 
RANDOM PROCESSES 
Mutation 
Sexual Reproduction 
gene flow
genetic drift

SELECTIVE PROCESSES
natural selection
Artifical selection

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

Mutation

A

A change in the DNA base sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sexual Reproduction

A

New gene combination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Gene Flow

A

Change due to genetic migration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Genetic Drift

A

Change due to a chance event

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Natural Selection

A

Environment drives change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Artificial Selection

A

Change is human-induced

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

What are the Mechanisms of variation?

A

Mutation
Sexual reproduction
Gene flow (Species moving)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the Mechanisms of change?

A 
Genetic drift (Chance event)
Natural selection (selection Pressures)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is speciation?

How does it happen?

A

Is the formation of a new species due to the divergence of isolated populations

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

The level of _____ between isolated populations will gradually increase the longer the populations are separated.

A

Divergence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

______ occurs when both ______ diverge to the extent that they can no longer interbreed and produce offspring

A

1) Speciation

2) Populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When can something provide evidence for evolution?

A

When it demonstrates change over time

e.g: Current forms differ from ancestral forms

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

What Provides evidence for Evolution?

A 
Fossils 
Selective breeding 
Comparative Anatomy 
Biogeography 
Comparative Embryology 
Molecular Evidence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are fossils and what do they provide?

A
  • Preserved remains of past life

- Allow comparisons with ancestral organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is selective breeding?

A

Human directed breeding patterns promote rapid diversification (i.e. change over time)

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

What is Comparative Anatomy and what does it suggest

A
  • Distinct species share a common body plan

- Suggests divergence from a common ancestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is biogeography?
What does it indicate?
What explains the exceptions to it?

A
  • Closely related species are closely located
  • Indicates divergence from a common ancestor
  • Exceptions explained by continental drift
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Comparative Embryology?

What does it suggest?

A
  • Species share similar embryonic development

- Suggestive of a common ancestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Explain Molecular evidence regarding Evolution

A
  • Closely related species share a greater degree of similarity in DNA and protein sequences.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Define fossil

Than define Fossil record and what it is for

A

Fossil - the preserved remains or trace of an organism from the remote past.

Fossil record - Is the totality of all fossils it shows changes that have occurred in organisms (evolution)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe what the
LAW OF FOSSIL SUCCESSION
is

A

Certain organisms appear in the fossil record in a consistant order - indicating an evolutionary sequence of development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What comes before what according to the law of fossil succession

A
  • Prokaryotes appear before eukaryotes
  • Ferns appear before flowing plants
  • Invertebrates appear before vertebrates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are TRANSITIONAL FOSSILS

A

They represent intermediary forms within the evolution of a genus
(the ARCHAEOPTERYX links the evolution of birds (wings/feathers) to dinosaurs (jaws/claws)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What involves the mating of animals with desired characteristics? and what is it an example of?

A

Selective breeding

a form of artificial selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

As human intervention drives selection, changes will occur over______

A

fewer generations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Give 3 examples of selective breeding

A
  • Draft horses (power) VS racing horses (speed)
  • Large variation in types of dog breeds
  • Cows selected for muscle mass (Belgian Blue)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are HOMOLOGOUS STRUCTURES

A

Anatomical features that share a common underlying structure despite having distinct functions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

A rapid diversification of the anatomical feature is a result of______

A

Adaptive Radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Closely related species will have more _____ in their homologous structures

A

Similarities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

The Pentadactyl limb of mammals is an example of a _______

A

Homologous structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

The theory of natural selection was proposed by ?

A

Charles Darwin (and Alfred Wallace)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the conditions for natural selection?

according to natural selection theory

A
  • There is genetic Variation between a given population
  • There is competition for survival due to the overproduction of offspring
  • Environmental selection pressures lead to differential reproduction
  • Organisms with beneficial adaptations re better suited for survival and more likely to reproduce and pass on genes
  • Over generations, there is a change in the allele frequency within a population (evolution)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What mnemonic can be used for Natural Selection?

A

ICE AGE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does ICE AGE stand for? and what does it explain

A

Explains Natural Selection

I : inherited variation
C : competition
E : environment pressures

A : adaptations
G : genotype frequency
E : evolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Natural selection can only occur if there is _____ among members of a species

A

Variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are the 3 main sources of variation

A

Sexual Reproduction
Mutation
Meiosis

(SMM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Describe MUTATION

A

A gene mutation is a change in the base sequence of a section of DNA coding for a particular characteristic / trait
- New alleles are formed via mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Which two ways can MEIOSIS promote variation within a species?

A

1) Crossing over

2) Random Assortment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Briefly explain CROSSING OVER

A
  • Occurs via synapsis during Prophase 1
  • Homologous chromosomes connect via chiasmata to form bivalents (or tetrads)
  • Chiasmata represent the points where genetic information has been exchanged
  • The non-sister chromatids that have exchanged DNA are called recombinants.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Briefly explain RANDOM ASSORTMENT specifically in humans.

A
  • During metaphase 1, homologous pairs line up in a random orientation
  • This means there is an equal chance of a resulting gamete containing either the maternal or paternal chromosome
  • As humans have a haploid number of 23, there are 2^23 gamete combinations (over 8 million possible gamete combinations)
45
Q

Explain Sexual Reproduction

A

Sexual reproduction fuses gametes from a paternal and maternal source, resulting in offspring with a combination of traits
Because fertilisation is random, offspring will receive different trait combinations every time, resulting in near infinite genetic variability.

46
Q

Populations will tend to produce ____ offspring than an environment can support

A

more

47
Q

What is the consequence of a overproduction of offspring?

A

A struggle for survival

48
Q

When there is an abundance of resources a population can achieve its ________

A

biotic potential

a maximum growth rate) (J-Curve

49
Q

More offspring means less resources are available to other members of the population is an example of what?

A

Environmental resistance

50
Q

Competition for resources will lead to an increase in mortality as populations reach a _________

A

Carrying capacity

S-curve

51
Q

Biotic potential VS Competition

on a graph which curve is exponential and which curve increases than levels put?

A

J curve - Biotic potential is exponential

S curve - Carrying capacity. Increases fast than levels out

52
Q

What are Selection Pressures

A

Selection pressures are external agents which may affect an organisms survival.
Organisms that are more likely to survive are more likely to reproduce and pass on genes

53
Q

What are examples of selection pressures?

A 
DENSITY DEPENDENT (lot of animals living close)
Predators 
Available resources
Nutrient supply 
Disease 
Accumulating wastes

DENSITY INDEPENDENT (closeness doesn’t matter)
Phenomena (e.g. fires)
Abiotic factors
Weather factors

Mnemonic: PANDA PAW

54
Q

What are ADAPTATIONS

A

Characteristics that make an organism suited to its environment

55
Q

What are the 5 types of adaptations?

A

Structural ( e.g. neck length of giraffe)
Behavioural (e.g. a possum playing dead)
Physiological (e.g. homeothermy (heat control))
Biochemical (e.g. lactose intolerance)
Developmental (e.g. ageing patterns)

56
Q

How do organisms pass on genes coding for their adaptations?

A

Sexual reproduction / Reproduction

57
Q

What determines the genetic variation within a population

A

The presence of alleles

58
Q

Alleles for a phenotypic (a trait we can physically observe) trait may be:

A

Beneficial - promote survival & reproduction
Detrimental - limit survival & reproduction
Neutral - not affect survival or reproduction

59
Q

Due to natural selection, the frequency of alleles will change across generations.
What type of alleles will become more and less common

A

Beneficial alleles will become more common

Detrimental alleles will become less common

60
Q

Allele frequencies will change in response to changing

A

Environmental conditions

61
Q

What is ADAPTIVE RADIATION ?

A

A rapid evolutionary diversification of a single ancestral lineage

62
Q

Adaptive radiation occurs when….

A

members of a species occupy a variety of niches with different environmental selection pressures
(members evolve different adaptations due to natural selection)

63
Q

Name an example of adaptive radiation

A

The variety of FINSH BEAKS on Daphne Major (Galapagos Islands)

64
Q

Give an example of Evolution in depth

A

PIGMENTATION OF PEPPERED MOTHS

  • this moth exists in two forms: light pigmentation vs dark pigmentation
  • during the industrial revolution, high levels of soot blackened the local trees
  • The black moth was better camouflaged and experienced less predation
  • The allele for dark pigmentation became more frequent as dark moths reproduced
  • Reduced soot output has recently led to the light variant becoming more common
65
Q

Give an example of Evolution

A

ANTIBIOTIC RESISTANCE IN BACTERIA

  • Staphylococcus aureus exists as two strains : drug resistant VS susceptible
  • If exposed to an antibiotic (methicillin), only the drug resistant strain survives
  • This increases the frequency of the drug resistant allele within the population
66
Q

What is Natural classification

A

involves grouping organisms according to common ancestry rather than common characteristics

67
Q

What is a level of classification called?

A

TAXA

68
Q

What does a TAXA include ?

A

All organisms derived from a single ancestor

69
Q

What are the rules of TAXA ?

A
  • Lower taxa MUST share all higher taxa

- Lower taxa are more closely related

70
Q

What are the advantages of natural classification?

A
  • Able to identify organisms by a global scheme
  • Shows how closely related organisms are
  • Allows determination of evolutionary links
  • Predictions can be made for new organisms
71
Q

What are the disadvantages of natural classification?

A
  • May require the reclassification of organisms when new evidence is discovered regarding an organisms evolutionary history
72
Q

All living organisms are classified into 3 domains.

What are they? and what goes in them?

A 
EUKARYA = all eukaryotic organisms 
ARCHAEA = all prokaryotic extremophiles 
EUBACTERIA = common pathogenic bacteria
73
Q

Compare all 3 domains

What has a: nucleus, histones, introns and 70s or 80s ribosomes

A 
Eukarya = Nucleus, histones introns and 80s ribosomes 
Archaea = Introns, histones and 70s ribosomes 
eubacteria = 70s ribosomes
74
Q

Archaea and eubacteria are both prokaryotic, archaeal cells possess certain features that are common to eukaryotes. What does this suggest?

A

Suggests Archaea and Eukarya share a more recent common ancestry than eubacteria

75
Q

List the names of the hierarchical taxa in the correct order

A 
Domain 
Kingdom 
Phylum 
Class 
Order 
Family 
Genus 
Species

DK PCOFGS

76
Q

Name a taxonomic example for a Animal

A

Human:

Eukarya
Animalia 
Chordata 
Mammalia 
Primate 
Hominidae 
Homo 
Sapiens
77
Q

Name a taxonomic example for plants

A

Rosa acicularis:

Eukarya 
Plantae
Angiosperms
Rosids
Rosales
Rosaceae
Rosa
Rosa acicularis
78
Q

Carl Linnaeus devised what in 1735?

A

The binomial system of nomenclature

a globally recognised classification scheme

79
Q

according to the binomial system every organism has a two part name: what are they and how do you write them?

A

Genus : written first and capitalised (Homo)

Species : follows in lower case (Homo sapiens)

80
Q

Name all the Plant PHYLA what goes in them

A

Bryophytes (liverworts and mosses)

Filicinophytes (Ferns)

Coniferophytes (conifers)

Angiospermophytes (flowering plants)

81
Q

What are the traits of BRYOPHYTES ?

A
  • No ‘true’ leaves, roots or stems
  • No vascularisation (no xylem / phloem)
  • Spores in capsule at end of stalk
82
Q

What are the traits of FILICINOPHYTES?

A
  • Have vascularisation
  • Spores in sporangia (where spores are formed) on underside of leaf
  • Have large leaves divided into leaflets
83
Q

What are the traits of CONIFEROPHYTES?

A
  • Have vascularisation
  • Have seeds (found in cones)
  • Leaves narrow with a thick, waxy cuticle (protective layer)
84
Q

What are the traits of ANGIOSPERMOPHYTES?

A
  • Have vascularisation
  • Have seeds (found in fruits)
  • Have flowers as reproductive organs
85
Q

Name all Animal Phyla and what goes in them

A

Porifera (sponges)

Cnidaria (Jellyfish and anemones)

Platyhelminthes (flatworms & tapeworms)

Annelida ( earthworms and leeches)

Mollusca (squids, slugs and snails)

Arthropoda (insects, spiders, etc)

Chordata (vertebrates)

86
Q

What are traits of PORIFERA?

A
  • Possess an asymmetrical body plan
  • Have no mouth or anus (have pores)
  • May have spicules (pointy things) for structural support
87
Q

What are traits of CNIDARIA?

A
  • Possess radial symmetry
  • Have a mouth but no anus (single opening)
  • Has tentacles & stinging cells (cnidocytes)
88
Q

What are traits of PLATYHELMINTHES?

A
  • Possess bilateral symmetry
  • Have a mouth but no anus (single opening)
  • Flattened body increases SA: Vol ratio
89
Q

What are traits of ANNELIDA?

A
  • Possess bilateral symmetry
  • Have a separate mouth and anus
  • Body composed of ringed segments
90
Q

What are traits of MOLLUSCA?

A
  • Possess bilateral symmetry
  • Have separate mouth and anus
  • May have a shell
91
Q

What are the traits of ARTHROPODA?

A
  • Possess bilateral symmetry
  • Have a separate mouth and anus
  • Have jointed appendages & exoskeleton
92
Q

What are the traits of CHORDATA?

A
  • Possess bilateral symmetry
  • Have a separate mouth and anus
  • Have a notochord (a primitive spinal cord)
93
Q

Vertebrates are a sub-phylum of Chordata in which the notochord forms a backbone. What are these sub phylum?

A 
Fish 
Amphibians 
Birds
Mammals 
Reptiles
94
Q

What is a Dichotomous key?

A

A Go to Q table dividing organisms into two categories

95
Q

Cladistics involves classifying organisms into groups of species called _______

A

Clades

96
Q

What does a CLADE consist of?

A

A single common ancestor and all of the descendants of that ancestor

97
Q

What is a CLADOGRAM ?

A

A tree diagram where branch points represent the splitting of two new groups from a common ancestor.

98
Q

What are branch points on a cladogram called and whats their purpose?

A

Named NODES
They represent speciation

The more nodes between groups = less related

99
Q

Historically, cladograms were generated based on shared structural characteristics. Why is this method limited?

A
  • Related species may have morphologically distinctive features (homologous structures)
  • Unrelated species may have morphologically similar features (analogous structure)

SO, structural characteristics are NOT a reliable indicator of evolutionary pathways

100
Q

what are the differences between homologous and analogous structures ?

A

Homologous:
Structure - look different
Cause - due to different selection pressures
Ancestry - DO share common ancestry
Evolution - Divergent (adaptive radiation)
Example - Pentadactyl limbs (in vertebrates)

Analogous:
Structure: Look similar
Cause: Due to common selection pressures
Ancestry: do NOT share a common ancestry
Evolution: Convergent evolution
Example: Fins (dolphin VS shark)

101
Q

Cladograms are now being generated by___________

A

comparing DNA or amino acid sequences

More differences: species less closely related
Amino acid differences will accumulate slower than DNA differences (due to degeneracy)

102
Q

what is mtDNA

A

Mitochondrial DNA

  • Inherited maternally (more direct lineage)
  • It lacks recombination (as mtDNA is circular)
  • Has a relatively stable (and high) mutation rate
103
Q

what is mtDNA used for?

A

Comparing species that are closely related

104
Q

Describe the concept of the MOLECULAR CLOCK

A

Some genes or protein sequences may accumulate mutations at a constant rate.
The time divergence can be calculated based on the total number of mutations.

105
Q

Analogous structures (convergent evolution) do NOT REPRESENT _______

A

common evolutionary descent

106
Q

Taxa may be reclassified if molecular data suggests_______

A

alternate evolutionary pathways

107
Q

Give an example of plant reclassification

A

Species in the Figwort family have been reclassified based on CHLOROPLAST DNA

108
Q

Give an example of animal reclassification

A

The Homininae sub-family was created to group gorillas and humans together

Biology HL (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions