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IB Biology > A4 Unity and Diversity of Ecosystems > Flashcards

A4 Unity and Diversity of Ecosystems Flashcards

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1
Q

What is biological evolution?

A

Change in the heritable characteristics of a population / change in allele frequency overtime in a population

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2
Q

What was Lamarck’s theory of evolution?

A

Adults acquired characteristics over their lifetime, based on environmental stressors and pass this on

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3
Q

Why was Lamarck’s theory of evolution falsified?

A

Offspring inherit DNA. Changes during lifespan cannot be passed on

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4
Q

What was Charles Darwin’s theory of natural selection?

A

Only traits are heritable can be passed on. Alterations to heritable material give rise to different traits. Some traits aid survival/reproduction, and organisms that survive are able to pass on successful traits. This means that the frequency of this allele increases.

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5
Q

What does it mean for a theory to be falsified?

A

Shown not to be true

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6
Q

What generates strong support for a theory?

A

If many lines of evidence fail to falsify it (i.e. evidence for lack of falsification)

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7
Q

What are three different forms of molecular evidence for evolution that are studied?

A

DNA
RNA
Proteins (indirect way to study DNA)

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8
Q

What patterns would be found in DNA comparisons that suggest evolutionary similarity?

A

A high level of DNA similiarity between species supports the idea of common ancestory with evolution occuring via small changes to DNA overtime

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9
Q

What are the Hox genes?

A

Gene family that plays a role in determining the body plan of organisms during development.

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10
Q

How are Hox genes related to evolution?

A

The similarity in these genes across very different types of organisms would be hard to explain without looking at common ancestry/evolution

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11
Q

What are phylogenetic trees?

A

Visual diagram that shows similarity via organisms being on closer branches.

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12
Q

What have we added onto Darwin’s theory of evolution?

A

That inheritance is due to DNA, which does not change during the lifetime.

That differences/variation arise because of changes to DNA due to mutation.

Variation is genetic

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13
Q

What is the outcome of Natural selection?

A

Evolution

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14
Q

What are the steps involved in natural selection (according to Darwin)

A

Differences exist in heritable material.

This leads to variation in a population.

There are threats to survival.

In this environment, some variations increase likelihood of survival.

Those with the adaptation produce more offspring, because they survive longer (survival of the fittest)

Since adaptation is heritable, the adaptation is passed onto their many offspring

Over many generations, there is an increased frequency of this adaptation + evolution has occured

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15
Q

What are some threats to survival?

A

Abiotic factors
Competition for resources
Predators + disease

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16
Q

What is fitness (in relation to survival of the fittest)?

A

Ability to pass on more offspring (by surviving longer)

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17
Q

How is a base sequence comparison of DNA molecular evidence for evolution?

A

More similiar the DNA is, the more closely related.

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18
Q

If evolution is true, similiar organisms will have…

A

Very similar DNA

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19
Q

What are the strengths and limitations of DNA modelling?

A

Difficult to isolate and sequence. Overly complex if not closely related

Provides more information. All differences are detected including silent mutations. Good for if closely related

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20
Q

When is RNA sequencing used?

A

Studying viral evolution, that only has RNA

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21
Q

How is RNA used for molecular evidence for evolution?

A

Using mRNA, base sequencing concept.
Usually difficult to sequence, harder to isolate

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22
Q

Where does most older data about molecular evidence for evolution come from?

A

Protein studies

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23
Q

How are proteins used as molecular evidence for evolution?

A

Compare amino acid sequences of a shared protein.

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24
Q

What are the strengths and weaknesses of using proteins for molecular evidence for evolution?

A

Easier to sequence and obtain

Less data/differences detected. Does not include silent mutations

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25
Q

What is selective breeding?

A

When breeders choose the males and females with the most desirable traits to breed

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26
Q

What is artificial selection?

A

Change in the frequency of heritable material caused by human selective breeding

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27
Q

What is a homologous structure?

A

Structures with similar internal structures used for different purposes

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28
Q

What are pentadactyl limbs?

A

Limbs with five digits. Same set of bones across organisms

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29
Q

What are analogous structures?

A

structures that carry out similar functions but are very different structurally

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30
Q

What is convergent evolution?

A

When independent species develop similar adaptations to similar environments

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31
Q

What are examples of organisms that have undergone selective breeding?

A

Modern corn
All modern dog breeds
Cannabis

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32
Q

How has modern corn been shaped by selective breeding?

A

Originated from teastine plant with very small, hard kernels. Large kernels and protective leaves were favoured. Across many generations, the modern corn we have today has been developed

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33
Q

How have all modern dog breeds been shaped by selective breeding?

A

All originate from the grey wolf. Breeders choose different prefered traits leading to different breeds

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34
Q

How has cannabis been shaped by selective breeding?

A

Breed for high THC content. Lead to the average THC content quadrupling over 23 years

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35
Q

What are examples of functional variations in pentadactyl limbs across animals?

A

Walking (most animals)
Hands (bipedal humans)
Fin (aquatic mammals)
Wing (bat0

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36
Q

What evolutionary pattern do homologous structures provide evidence of?

A

Divergent evolution

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37
Q

What is divergent evolution?

A

When a common ancestor evolves into increasingly different species overtime, because of different selection pressures

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38
Q

Are central nervous systems considered to be homologous or analogous structures?

A

Analogous. Many have similar structures but no common ancestor

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39
Q

How is artificial selection evidence for natural selection?

A

Similarity between the processes and the similar end result offer evidence that the natural selection model is correct

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40
Q

How is natural selection different to artifical selection?

A

Different selection pressures

Natural: pressures in environment choose which survive
Artificial: human preferences are the selection pressure

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41
Q

How are artificial and natural selection similar?

A

Both start with genetic variation
Both end with one variation with more offspring, causing an increase in frequency

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42
Q

What is an example of divergent evolution?

A

Mammals (common ancestory) with pentadactyl limb (homologous structure)

Due to different selection pressures, this structure developed into:
Hoove/leg (Horse)
Fin (dolphin)
WIng (bat)

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43
Q

What is an example of convergent evolution?

A

Different ancestors: insect, bird, mammal

Similiar selection pressure: ability to fly in sky

Leads to:
Wings with no bones (butterfly from insect)

Wings with one bone and feathers (robin from bird)

Wing with bone and skin (bat from a mammal).

No recent common ancestor. Analogous structure: wings.

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44
Q

What is speciation?

A

Formation of two new species by splitting an existing species

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45
Q

What is reproductive isolation?

A

When two species are unable to successfully interbreed -> no gene flow/exchange of genetic material. Can lead to speciation

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46
Q

What is geographical isolation?

A

Physical barrier that leads to no contact between male and female (mating not attempted). Type of reproductive isolation

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47
Q

What is sympatric speciation?

A

When speciation occurs with no physical barrier / new species arises within same habitat where mating could occur but didnt

48
Q

What is allopatric speciation?

A

When speciation occurs because of a physical barrier. Causes lack of contact and distinct habitats

49
Q

What is behavioural separation?

A

Isolation when mate-attracting behaviours are different between groups, to ensure successful breeding

50
Q

When is behavioural separation most common?

A

species with elaborate rituals

51
Q

What is temporal separation?

A

Different mating/release of gametes times that can lead to sympatric speciation

52
Q

What can temporal separation be good for?

A

Preventing unsuccessful mating

53
Q

What is adaptive radiation?

A

When similar but distinct species evolve rapidly from a common ancestor. Groups move into different niches and therefore, with different adaptations

54
Q

What is required for speciation to occur?

A

Reproductive isolation
Differential selection

55
Q

How do speciation and extinction interact to impact the number of species on Earth?

A

Opposite forces to control. Speciation = new species added. Extinction = new species removed

When speciation > extinction, increased biodiversity

56
Q

What is an example of adaptive radiation?

A

Darwin’s Finches. 14 species from 1 common ancetor. Migrated + adapted to different food sources, therefore very different beaks

57
Q

What is allopatric speciation a product of?

A

a geographic barrier that prevents mating

58
Q

What is differential selection?

A

When exposure to different selection pressures causes the isolated populations to evolve.

59
Q

What causes adaptive radiation usually?

A

Migration event

60
Q

What is hybridisation?

A

Fertilisation of gametes from one species by gametes of another species, forming unsuccessful offspring who cannot survive/reproduce

61
Q

What are interspecific hybrids?

A

The result of (usually) artifical hybridisation betweeen two species.

62
Q

What is a polyploidy?

A

When a species has three or more of each chromosome, due to an error in meiosis or hybridisation

63
Q

What is autotetraploidy?

A

Formation of a polyploid organism from members of the same species

64
Q

What is allotetraploidy?

A

Formation of a tetraploid via combining gametes from two different diploid species.

65
Q

What is abrupt speciation?

A

rapid formation of a new species over a few generations (can occur when new species are formed via tetraploidy)

66
Q

Why are mules sterile?

A

Incompatible chromosomes. Horses = 64 chromosomes. Donkey = 62 chrosomes. Therefore, mule = 63 chromosomes. Uneven numbers = difficult meiosis b/c pairing of chromosomes is needed for functional gametes

67
Q

Why have so many species evolved barriers to prevent hybrid offspring from developing?

A

B/c the genetic differences lead to
Miscarriage (reduced hybrid viability)
Born fragile/diseased (reduced hybrid viability)
Infertile (hybrid sterility -> gametes do not form in meiosis, especially because of odd number of chromosomes.

This is a bad outcome because
- Waste of energy
- Poor for survival of the fittest

68
Q

What are barriers to hybridisation?

A

Behavioural isolation
Temporal isolation
Incompatible genitals

69
Q

What is tetraploidy?

A

4 sets of every chromosome

70
Q

Why are autotetraploidies not always classified as their own species, even though they are?

A

Often very similar appearance

71
Q

What is the process of autotetraploidy?

A

Diploid parent cell goes through a genetic event to make them an autotetraploid.
When meiosis occurs, they form diploid gametes (b/c even chromosome numbers)

If they reproduce with another tetraploid, they have tetraploid offpsring and become a self-sustaining species.

If they reproduce with a diploid species, this leads to a sterile triploid offspring

72
Q

Are allotetraploids classified as their own species?

A

Yes!

73
Q

What is allotetraploidy a result of?

A

Hybridisation

74
Q

What is the process of allotetraploidy?

A

Diploid parents (AA) + Diploid parent (BB) go through meiosis. Hybridisation produces a sterile hybrid (AB).
A genetic event occurs, making the hybrid an allotetraploidy.
Meiosis makes diploid gametes, that can only reproduce together.
This leads to tetraploid offpsring, and a sustainable species that only reproduces within itself

75
Q

What is biodiversity?

A

variety of living organisms in all forms, levels and combinations

76
Q

What is species richness?

A

Measure of biodiversity that specifically considers the number of different species in a community

77
Q

What is species evenness?

A

Description of the distribution (%) of the species in an ecosystem

78
Q

What is the gene pool?

A

All the alleles of a population

79
Q

What are the three types of biodiversity?

A

Ecosystem diversity
Species diversity
Genetic divserity

80
Q

What is anthropogenic species extinction?

A

Extinction caused by humans

81
Q

What are the five major causes of the current sixth mass extinction?

A

C: climate change
H: habitat loss
I: invasive species
P: pollution
O: overharvesting

82
Q

What is overharvesting?

A

Removing plants and animals for food/medicine/materials/fishing faster than they can regenerate

83
Q

What is habitat destruction?

A

Destroying ecosystems for agriculture/homes/urbanisation

84
Q

What is an invasive species?

A

Introduction of an alien species who outcompete endemic species, leading to extinctionW

85
Q

What is pollution?

A

Release of substances into the environment that directly/indirectly cause harm to living organisms

86
Q

What is global climate change?

A

Change of temperature faster than natural selection (leading to temperatures out of the abiotic zone of tolerance)

87
Q

What are some causes of ecosystem loss?

A

Land use for agriculture
Urbanisation
Overharvesting
Mining and smelting
Building dams
Diversion of water for human use
Overfertilisation
Climate change

88
Q

What are some forms of data that can be gathered for evidence of a current biodiversity crisis?

A

Decrease in population size
Calculations of species diversity
Number of threatened species
Change in range of species
Genetic diversity measured within species

89
Q

What are two organisations that release data on biodiversity loss?

A

IPBES
IUCN

90
Q

What is the IPBES?

A

Intergovernmental Science-Policy Biodiversity and Ecosystem Services

Published a report with guidelines for policy makers. Does data pooling and updates

91
Q

What is the IUCN?

A

International Union for Conservation of Nature. Make red list for all species rating their current level of threat

92
Q

What are three extinction case studies?

A

North Island Giant Moa
Carribean Monk Seal
Mount Glorious Torrent Frog

93
Q

What is the extinction case study of the North Island Giant Moa?

A

1000 years ago
B/c overhunted for food by Maoris
New Zealand

94
Q

What is the extinction case study of the Carribean Monk Seal?

A

1957 last sighting
Blubber was boiled and turned into oil (main source of power for lamps)
the Carribean

95
Q

What is the extinction case study of the Mount Glorious Torrent Frog?

A

By 1980
Deforestation + alien feral pigs (ate them)
Rainforests in Northeastern Australia

96
Q

What is the ecosystem loss case study of the Mixed Dipterocarp Forest?

A

In Asia
Current
Logging for area for palm oil + using trees

97
Q

Why is the Amazon Rainforest being deforested?

A

Agricultural practices
Deforestation

98
Q

What is ecosystem biodiversity?

A

Diversity within the biomes of the world

99
Q

What to consider in terms of ecosystem biodiversity?

A

Amount of biomes, areas covered by biomes, % degradation

100
Q

What is species diversity?

A

Diversity with the amount of species

101
Q

What to consider in terms of species diversity?

A

Amount of species, sum of species richness/evenness, population sizes, % endangered, ranges

102
Q

What to consider in terms of genetic diversity?

A

Amount of alleles in gene pool, balance of alleles

103
Q

What is Simpson’s Diversity Index?

A

Measure of diversity

D =
N x (N -1)
/
Σ n (n - 1)

Where N = total number of species
n = number of that species

104
Q

When was the biodiversity crisis first identified?

A

1970

105
Q

What criteria does the EDGE of existence project use to identify animal needing conservation efforts?

A

ICUN ranking
DNA sequencing information for unique evolutionary history

106
Q

What do anthropogenic impact come from?

A

Human need for food and shelter

Food = hunting and harvesting
Shelter = habitat loss

107
Q

How has the increase in human population size increase contributed to the biodiversity crisis?

A

Increase in population size

Leads to
1. More need for food -> overharvesting

  1. More need for shelter (and urbanisation) -> habitat loss
  2. More travel (including airtravel) -> invasive species, pollution
  3. Industrial revolution (more people = more fossil fuels used) -> pollution, climate change
108
Q

What are in situ conservation efforts?

A

Management of biodiversity within natural habitat

109
Q

What are ex situ conservation efforts?

A

Management of biodiversity outside of natural habitat

110
Q

What are in situ conservation efforts examples?

A

Establishment of national parks and nature preserves

Rewilding: introduce helpful species and/or remove potential human interferences (dams, invasive species, etc.)

Reclamation of damaged areas (replanting, short term management)

111
Q

What is an example of rewilding?

A

Wolves in Yellowstone

112
Q

What are examples of ex situ conservation efforts?

A

Establish a botanical garden (creation of artificial habitat for species)

Zoos with breeding programs for endangered animals (artificial insemination across different zoos -> more genetic diversity)

Seed banks and animal tissue banks
(create before endangered)

113
Q

How are botanical gardens different to national parks?

A

Botanical gardens are artificial and created outside of natural habitat, while national parks are natural

114
Q

What do tissue banks need?

A

Cryogenic care

115
Q

What can seed banks be for?

A

Reclamation of damaged areas, botanical gardens

116
Q

What can animal tissue banks be used for?

A

Cloning

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