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Biology > Evolution > Flashcards

Evolution Flashcards

1
Q

What are the other names for the theory of abiogenesis?

A
  • Autogenesis

* Theory of spontaneous creation

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2
Q

What did the theory of abiogenesis state?

A

This theory stated that life did not come from outer space, it was instead spontaneously generated from non living matter.

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3
Q

Who disproved the theory of abiogenesis?

A

This was disproved by many scientists out of which the most prominent are

  • Louis Pasteur - swan neck exp.
  • Francesco Redi - Maggot on jar
  • Spallanzi - He created a boiled nutrient broth
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4
Q

The Biochemical origin of life was proposed by…?

A

Oparin and Haldane

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5
Q

3600 yrs ago the atmosphere was devoid of ……………………

A

free oxygen

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6
Q

Where did Oparin Haldane say that the synthesis of the main constituents of life take place ?

A

He called it the primordial soup, which is now referred to as the sea.

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7
Q

Which exp. shows that reducing atm is required for abiotic synthesis ?

A

Miller - Urey’s exp. This experiment suggested that the presence of free oxygen would modify the intermediate products and would have hence changed the outcome.

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8
Q

What are Coacervates?

A

These are clumps of organic macromolecules present in the form of a colloidal particle and is capable of growth and replication. Coacervates contain proteins , nucleoproteins etc. and because of the resemblance to protoplasm they are called the prebiotic structures.

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9
Q

The first sign of self perpetuating life was displayed by …………?

A

nucleic acids , as they had the ability to replicate and showed hereditary function.

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10
Q

The fist organisms were ….. ?

A

Heterotrophic, anaerobic, virus like nucleoprotein substances

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11
Q

Which structures did Oparin say resembled bacteria.

A

Coacervates with nucleoproteins

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12
Q

What kind of autotrophism came first?

A

Chemo Autotropism

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13
Q

What led to the usage of water instead of sulphides

A

The development of chlorophylls from bacteriochlorophylls.

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14
Q

The first oxygenic and aerobic photoautotrophs were ……………?

A

Cyano bacteria

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15
Q

What does congnogeny mean?

A

It involves the diversification of prokaryotes and eukaryotes into chem and photo autotrophs and heterotrophs and further cell differentiation and later development of multicellular organisms.

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16
Q

Why are coacervates not considered possible precusors of life?

A

This is because though the can replicate they do not have a lipid or protein membrane and hence cannot reproduce.

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17
Q

What are the two protobionts observed in Miller Urey’s experiment?

A

Coacervates and Microspheres

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18
Q

Who obtained proteinoid microspheres?

A

Sydney Fox

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19
Q

What are Liposomes?

A

Compartmentalised structures that enclose fluid/liquid.

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20
Q

What impact did cyano bacteria have on the evolution of life?

A

Cyanobacteria released healthy amounts of oxygen

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21
Q

What impact did cyano bacteria have on the evolution of life?

A

Cyanobacteria released healthy amounts of oxygen into the atmosphere and converted the reducing atm into an oxidising one.In doing so it also synthesised O3 and created the ozone layer.

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22
Q

Introduction of free oxygen into the atm. resulted in the oxygen revolution. Explain the term.

A

Ultimately the appearance of oxygen results in the abstinence of abiotic synthesis.

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23
Q

What is the definition of a characteristic?

A

They are the details of a particular trait w.r.t. appearance and behaviour.

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24
Q

What did Darwin conclude based on his observations?

A

He concluded that all living organisms share similarities to varying degrees and they may have common ancestors.

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25
Q

The geological history of the Earth correlates with the biological history of the Earth.

A

Just a statement.

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26
Q

What kind of fitness did Darwin refer to when he postulated the theory of natural selection?

A

Reproductive fitness. He believed that an organism more adapted to a certain environment would produce more offspring than the others.

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27
Q

When did the free living Eukaryotes originate?

A

They originated 1.5 billion years ago.

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28
Q

Which book did Darwin publish?

A

On the Origin of Species

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29
Q

What is a fossil?

A

Fossils are the preserved remains of the hard parts of an organism in rock.

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30
Q

Which rocks are the richest in fossils?

A

Sedimentary

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31
Q

What are missing links/ transitional forms?

A

The extinct fossil organisms that show characters of the groups are called missing links.

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32
Q

What is morphology and what is anatomy?

A

Morphology: external structure
Anatomy: internal structure

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33
Q

Homologous organs are…? Examples…?

A

Homologous organs are those with similar anatomy but different functions.

e. g. *Arrangement of bones in the forelimbs of Man, Cheetah, Bat and Whale.
* The hearts of various vertebrates have varied degreed of specialisation pertaining to the environment they are from.
* The brains of organisms
* Thorn of Bougainvillea and Tendril of Curcubita ( modifications of axial buds)

34
Q

What is biochemical or molecular homology? Examples?

A

This refers to similarities at a molecular level.

e. g. *The proteins found in man and ape blood are the same
* Some genes can be traced back to different oragnisms.

35
Q

What is adaptive radiation?

A
  • The process of evolution which involves the migration of a particular species from one geographical location to other areas.
  • Evolution which because of competition for natural resources cause organisms of a particular species to develop into other species which live in other habitats.
36
Q

In which major ways did Darwin’s finches differ from each other.

A

They varied in the shape of their beaks and feeding habits.

37
Q

Darwins Finches seem to have evolved form…..?

A

Seed eating finches

38
Q

What is biological evolution?

A

This refers to a genetic change in a population that is inherited over multiple generations.

39
Q

What are the other names for Lamarck’s theory?

A
  • Theory of inheritance of Acquired Characters.

* The theory of use and disuse of organs.

40
Q

What were the four postulates of Lamarck’s theory?

A
  • Internal sources tend to increase the size of the body.
  • Formation of new organs is a result of need or want.
  • Development of the power of an organ is in direct relation to its use.
  • All changes acquired by the organism in its life time are transmitted to its offspring via inheritance.
41
Q

Who refuted Lamarck’s theories?

A

Weismann. He gave the theory of germ plasm.

42
Q

What was the main concept of Darwin’s theory?

A

natural selection

43
Q

What were the main features of Darwin’s theory?

A
  • High rate of reproduction
  • Limited resources
  • Variation
  • Struggle for existence
  • Survival of the fittest
  • Natural selection
  • Origin of new species
44
Q

Who came up with the phrase, survival of the fittest?

A

Herbert Spencer

45
Q

What integral part of evolution did Darwin ignore?

A

Darwin ignored variation caused due to mutations.

46
Q

De Vries mutation theory was based on what observation?

A

He observed that a certain variety of Primrose showed characteristic differences w.r.t. to the normal variety.

47
Q

What did Vries call these these sudden variations?

A

Saltation

48
Q

What are the four main postulates of the mutation theory?

A
  • They occur from time to time in a naturally breeding env.
  • they are heritable
  • They are large and sudden unlike Darwin’s variations that are small and directional
  • They can occur in any direction
49
Q

What is variation?

A

Variation is a process whereby closely related organisms come to differ amongst themselves.

50
Q

What kind of variation can take place in evolution.

A

Heritable variation

51
Q

How is a mutation defined?

A

Mutations are sudden hereditary changes in the genetic make up of an organism other than that caused by the recombination of genes during meiosis.

52
Q

what is the definition of speciation?

A

Speciation refers to the evolution of a new species.

53
Q

What is the Hardy Weinberg principle ?

A

This principle states that a population stays in genetic equilibrium if it is not undergoing any change.

54
Q

What is a gene pool?

A

The gene pool is the total no. of genes and their alleles in a population. Thus a gene pool will have all the possible genotypes.

55
Q

What are the main features if the Hardy Weinberg principle?

A
  • Allele frequencies in a population remains constant
  • the gene pool remains constant
  • the sum total of all the allelic frequencies = 1
56
Q

What is allelic frequency?

A

It is the frequency with which a particular allele occurs in a population.

57
Q

Which five characters effect the Hardy Weinberg principle?

A
  • gene migration
  • Genetic drift
  • Mutation
  • genetic recombination
  • natural selection
58
Q

What is gene migration?

A

This refers to the movement of alleles form one population to another.

59
Q

What is gene flow?

A

genes are being exchanged btw two populations in such a way that it results in the formation a new homogenous population.

60
Q

What are the two ways in which gene migration can occur?

A
  • Movement of a certain part of a population to another area.
  • Interbreeding of different populations.
61
Q

What is the genetic drift also called?

A

Seawall affect

Non-directional factor

62
Q

What is genetic drift?

A

This refers to the change in gene frequency by chance in a small population.
OR
The random of loss of genes in small population
OR
Mechanism of evolution responsible for random changes in a gene pool.

63
Q

What is genetic equilibrium?

A

This is when the gene pool remains unchanged. i.e. it remains constant

64
Q

How is the Hardy Weinberg principle used?

A

It is used to mathematically detect an evolutionary change

65
Q

Just an note:

A

Genetic drift tends to reduce the genetic variation in a population.

66
Q

The causes of variations may be classified into two types what are they?

A
  • Environmental conditions: These are non heritable and somatogenic.
  • changes in gene pattern: This refers to variation caused due to sexual reproduction; distribution due to homologous genes, crossing over, dual parentage , random recombinations.
67
Q

What is a mutation?

A

This is a SUDDEN hereditary change in the genetic make up of an organism which is caused by methods other than genetic recombination. This alters the PHENOTYPE of an individual.

68
Q

How does gene mutation affect the variation in a population?

A

Gene mutation may lead to the occupation of one locus by multiple genes which leads to the increase in the size of the gene pool.

69
Q

How does gene recombination affect the frequency of alleles in a gene pool of a population?

A

Genetic recombination doesn’t affect it directly, though this combination could lead to the production of new superior variants.

70
Q

In which way can one maintain the genetic variety of genes in a population.

A

By maintaining a gene bank. (plants)

71
Q

What is a pre-requisite for the formation of a new species?

A

Interruption of gene flow. This is because gene flow helps maintain a common gene pool btw two populations , hence reducing the variation btw them.

72
Q

Genetic drift is driven by chance. This goes against what?

A

Darwin’s theory of natural selection. Genetic drift occurs by chance and not by selection

73
Q

What is the Founders effect?

A

This refers to the formation a new population from an original population with a gene frequency entirely different from that of the original population.

74
Q

What is the bottleneck phenomenon?

A

This refers to the random reduction of the population which changes the gene pool.This phenomenon is known as population crash

75
Q

The effects of natural selection on different traits can be ….?

A
  • Stabilising
  • Disruptive
  • Directional
76
Q

What is stabilising character?

A

This refers to the situation when nature favour the mean character. e.g. sickle cell anaemia

77
Q

What is directional selectional?

A

This is when nature chooses to select in the favour of one of the extremes characteristics. e.g. industrial melanism.

78
Q

Imp. notes w.r.t. directional selection

A

*individuals with a more extreme form of a trait have a greater fitness than individuals with a medium form of a trait.

79
Q

What is disruptive selection?

A

It is the rarest form selection. In this case, pressure faced by the population in an external environment causes nature to prefer the extreme traits of a character. This will eventually lead to diversification (increased variation) and the population will split into two different groups.

80
Q

What is disruptive selection?

A

It is the rarest form selection. In this case, pressure faced by the population in an external environment may cause the favouring by nature of two phenotypes. As a result selection will push away from the mean characteristic and favour the two extreme phenotypes. e.g some fish

81
Q

How many evolutionary forms of man has there been, and what are they?

A 
A) Prior to Ape man
*Dryopithecus
*Ramapithecus
B) Ape-men and Prehistoric men
*Australopithecus
*Homo habilis
*Homo erectus
*Java ape man - homo erectus erectus
C) True men including the Living modern man
* Neanderthal
*The living modern man (Homo sapiens sapiens)

Biology (6 decks)

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