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BIOLOGY > EVOLUTION > Flashcards

EVOLUTION Flashcards

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1
Q

what is evolution

A
  • a general term that may be defined as a change over time that occur in chemicals, matter, solar systems and language
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2
Q

what is biological evolution

A
  • can be described as a genetic changes in a population of living organisms that are inherited over successive generations due to natural selection ultimately resulting in a new species
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3
Q

what is macro evolution

A
  • this is the development of new life forms or species form earlier life forms over many generations
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4
Q

what is micro evolution

A

the variations that occur within a species. small changes originate in the gene pool resulting in small changes in the genotype of the species - these changes are passs onto the the offspring

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5
Q

is evolution a hypothesis or a theory

A
  • a scientific theory
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6
Q

what is the origin of ideas about origins

A
  • the earth was created 4.6 billion years ago and we evolved from one common ancestor that lead to the enormous biodiversity we currently have
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7
Q

what are the 5 factors that are evidence of evolution

A

fossil records
modification
biogeography
genetics
other forms of evidence (comparative biochemistry; vestigial organs and comparative embryology)

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8
Q

what are homologous structures

A

similar structures with the same body plan that perform different functions - these then used to provide evidence of a common ancestor

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9
Q

what is biogeography

A
  • the study of the distribution of existing and extinct plant and animal species in specific geographical regions.
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10
Q

what are the 3 major observations when studying the natural environment

A
  • biodiversity
  • organisms are well adapted
  • continuous changes
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11
Q

erasmus darwin

A

his ideas
- single common ancestor
- similarities of species mean the one species developed from another
- artificial selections and metamorphosis

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12
Q

jean baptiste de lamarck

A

his theory
- the use or disuse of organs may cause organs to increase or decrease in size
- during lifetime organisms acquire certain changes in characteristics that are inherited by their offspring

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13
Q

alfred wallace

A

worked along side charles darwin to publish an article on natural selection

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14
Q

charles darwin

A

4 main observations
- individuals of population produce more offspring than required to ensure survival
- a great deal of variation occurs within a population
- some individuals are better adapted and more likely to reproduce
- characteristics are transferred from surviving parents to offspring

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15
Q

what is darwin’s theory of natural selection

A
  • a large number of offspring produced
  • variation in a population
  • struggle for survival
  • survival of the fittest
  • inheritance of favourable characteristics
  • change occurs over time
  • new species form
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16
Q

what is punctuated equilibrium

A
  • the fossil records show us fast and rapid change not gradualism like darwin suggests - either the species could not adapt and died or it did but rapidly leading to speciation
  • it explains the absence of transitional fossils
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17
Q

what is natural selection

A
  • survival of the fittest “nature decides”
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18
Q

what is artificial selection

A
  • in the deliberate breeding of plants and animals for desired characteristics that would not necessarily benefit the survival of offspring - sheep for wool, race horses for speed etc
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19
Q

differences between natural and artificial selection table

A

N
: environment acts as selection pressure
: characteristics are advantageous for survival in natural environments
: maintains variation
A
: humans decide
: characteristics not necessarily advantageous
: decreases variation

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20
Q

two types of variation

A

continuous - a range in phenotypes from the same characteristic forms a spectrum
- a genetic characteristic may be controlled then more than 1 gene (poly genetic) and each gene may have multiple alleles - the more alleles that control a characteristic the greater the variation of possible gene combinations (eg human height)
discontinuous - phenotypes fit into separate categories eg blood type - you can only be one

21
Q

What are the conditions essential for fossilisation

A

Rapid burial
High pressure
Low oxygen

22
Q

What is divergent evolution

A

Where organisms develop from a common ancestor but follow different evolutionary paths

23
Q

What is convergent evolution

A

Where organisms are not related but develop structures for similar environments completely independent of each other

24
Q

What are analogous structures

A

Preform same function but did not originate from a common ancestor

25
Q

What are analogous structures

A

Preform same function but did not originate from a common ancestor

26
Q

What is the theory relating to the flightless birds

A

May have developed from a common ancestor, the birds were separated when Gondwanaland broke apart - the climate and habitat changes as a result of continental drift - the birds adapted and a new species developed due to the mutations and selections in various environments

27
Q

What are 3 other forms of evidence (not the main 5)

A

Comparative biochemistry
Vestigial organs
Comparative embryology

28
Q

What is speciation

A

The formation of species increases the range of organisms on earth and thus increases biodiversity

29
Q

What is a species

A

A group of organisms that interbreed to produce fertile offspring

30
Q

What is extinction

A

The loss of species decreases the range of organisms on earth and thus decreases biodiversity

31
Q

What is a population

A

A group of organisms of the same species that live in a particular place and at a particular time with the ability to freely interbreed

32
Q

What is a gene pool

A

A total number of allelles of all reproductive individuals in a particular population

33
Q

What is a gene flow

A

The exchange of alleles between population

34
Q

What is reproductive isolation

A

When a new species arise from an existing species, the two species can no longer interbreed: there is therefore no gene flow and they become isolated from each other in terms of reproduction

35
Q

When can reproductive isolation occur

A

When the species is separated geographically
Or when they occupy the same area (new species arise)

36
Q

What is genetic variation in a species usually caused by

A

Genetic recombination - meisosis( crossing over and random assortment of homologous pairs )
- reproduction (random mating and random fusion of gametes)
Mutations - gene mutations (change in base sequence - either harmful, neutral or beneficial)
- chromosome mutation (eg Down syndrome)

37
Q

Mutations lead to genotypic variations in population, what are 2 examples

A
  • finches of the Galapagos island
  • white lions
38
Q

What is inbreeding

A

Crossing of closely related individuals - usually occurs in mostly treated species where there are limited numbers of individuals or in populations with small isolated gene pools
Bc closely related individuals share more alleles it leads to a limited genotypic and phenotypic variation
Increase in homozygosity - if both recessive genes are carrying harmful mutations they will be expressed in the phenotype therefor passed to next gen

39
Q

List 2 advantages and disadvantages of inbreeding

A

+ produces predictable offspring, recessive genes can be isolated
- high mortality rate, offspring can become sterile

40
Q

What are the 2 genetic disorders that occur in humans as a result of inbreeding

A

Haemophilia
Tay seach’s

41
Q

What is outbreeding

A

The crossing of unrelated individuals resulting in offspring that are genetically different-
Promotes heterozygosity where alleles differ from each other and increase genetic variation

42
Q

List 2 advantages and 2 advantages of outbreeding

A

+Genetic variation increases, reintroduces lost charactistic
- less predictability in offspring, typical characteristics are lost

43
Q

Explain the founder effect

A

A loss of genetic variation when a new population is formed from a small number of individuals moving to a new area - the gene pool will only contain genes from the founding members - according to evolution the isolated pop will become so different to the parent pop it can eventually form a new species

44
Q

What are the 2 main types of speciation

A

Geographic (allopatric) speciation
Sympatric speciation

45
Q

Define allopatric speciation

A

Is when a new species arised from an existing species when the populations are separated by a geographical barrier
These two populations are reproductively isolated and there is no gene flow
Natural selection occurs independently in each area and the two gene pools become very different in phenotype and genotype
Eventually a new species develops

46
Q

Define sympatric speciation

A

Is when a new species arise from an existing species in the same geographical area
The new species can become isolated from the ancestoral species with respect to reproduction even if they occur in the same area
Sympatric speciation can occur as a result of polyploidy plants (multiplication in chromosome no.) and hybrid species (breeding of unrelated individuals [different species])

47
Q

What are the 2 main groups of reproductive isolating mechanisms

A

Pre zygotic
Post zygotic

48
Q

What are some examples of pre zygotic isolation

A

Breeding at different times of the year
Species specific courtship
Adaptations to plant to different pollinators
Physical Incompatibility in animals to prevent fertilisation
Occupying different habitats in same environment

49
Q

What is an example of post zygotic isolation

A

Development of sterile offspring in hybrids

BIOLOGY (7 decks)

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