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BIOL 1020 FINAL > Topic 13: Evolution > Flashcards

Topic 13: Evolution Flashcards

1
Q

An organisms complete genetic makeup is contained within its?

A

Genome

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2
Q

Genomes can vary in what?

A

size, number of genes, and gene density between organisms

eukaryotes- genomes tend to be larger in most cases

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3
Q

Gene densities tend to be higher in what?

A

of genes per length of DNA
-higher in prokaryotes
-shorter DNA but still many genes results in higher densities

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4
Q

Multicellular eukaryotes have lots of non-going DNA and many multigenerational families contained within their genomes, what are they?

A

-introns (DNA between protein coding genes)
*20%
-gene-related regulatory sequences
*5%
-unique single copy DNA
-pseudogenes (former genes that no longer function)
-repetitive DNA (present in multi copies in the genome)
-simple DNA repeats

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5
Q

What are multigene families?

A

collections of 2 or more identical or similar genes

ex. global genes that make up hemoglobin

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6
Q

What are transposable elements?

A

are stretches of DNA that can move from one location to another within the genome
-moves via recombinant events

  1. Transposons-move by an intermediate enzyme called transposase (‘cut and paste’)
  2. Retrotransposons- move via an RNA intermediate (‘copy and paste’)
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7
Q

How to Transposable elements contribute to genome evolution?

A
  1. promote recombination
  2. disrupt celular genes or control elements
  3. carry entire genes or axons to new locations
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8
Q

What happens if a transposon jumps into the middle of a protein-coding gene?

A

it could prevent the normal transcription of the gene

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9
Q

What happens if a transposon jumps into the middle of a regulatory gene?

A

it increases or decreases the production of one or more proteins

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10
Q

What happens to genome evolution if duplication of entire chromosomes sets?

A

errors in meiosis (such as failure to separate homologous chromosomes can result in polyploidy
-usually lethal, some cases can facilitate gene evolution
-duplicated genes have mutation that occur that allow them to function differently
-pass these duplicated genes to offspring
-many plants evolve this way

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11
Q

What is divergent evolution? ***

A

lecture 32 slide 9

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12
Q

Duplicated of gene-sized regions of DNA can contribute to genome evolution how?

A

errors in meiosis can cause duplication of chromosomal regions
-unequal crossing over during prophase 1 can results in chromosomal deletions in one chromosome and chromosomal duplicated in the other

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13
Q

How can human global genes evolve from duplication events?

A

-a single global gene underwent duplication and divergence
-mutations in the diverged global genes results in two different functioning genes on two different chromosomes

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14
Q

How can related genes have different functions after duplication and divergence?

A

-lecture 32 slide 12

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15
Q

How do exons lead to genome evolution?

A

EXONS ARE DNA sequences THAT CODE FOR PROTEINS

-can be duplicated or deleted in homologous chromosomes due to unequal crossing over in meiosis
-duplicated exons could code for more of the protein, resulting in protein stability within it domains, increase ability to bind to ligands

IF different axons are moved within a gene or between two different genes due to errors in recombination during meiosis, this exon shuffling could lead to new proteins with novel functions

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16
Q

The more similar in sequences the genes and genomes of two species are they are closer or further in evolutionary history?

A

the more closely related they are in their evolutionary history

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17
Q

What does it mean to be highly conserved?

A

genes that have remained similar over time are highly conserved

18
Q

What does comparing genes show us?

A

allows us to see if certain genes are evolving faster in certain organisms

19
Q

Genes that code for transcription factors evolve faster or slower?

A

evolve faster than others

20
Q

Comparing genomes within the same species allows us to see what?

A

genetic differences that lead to diverse phenotypes
-most genetic variation appears in the form of single nucleotide polymorphisms (SNPs), which are single base pair sites found in at least 1% of the population

-also occur from copy-number variants, where individuals have one or multiple copies of a gene or gene region (caused by duplication) father than one copy per homologue

21
Q

What is evolutionary development?

A

is the study of developmental processes of different multicellular organisms
-goal: to understand how processes evolved and how these changes modify existing organismal features or lead to new ones

22
Q

What is a homeobox?

A

180-nucleotide sequence that goes for a 60-amino acid homeodomain

23
Q

What are homeotic genes?

A

master regulatory genes that control placement and spatial organization of body parts in organism by controlling the development fate of groups of cells

24
Q

What was Charles Darwin scientific explanation for 3 observations?

A
  1. the striking way organisms are suited for life in their environment
    -natural selection, adaptations
  2. the many shared characteristics
    -(unity) of life
  3. the rich diversity of life
    -descent with modification
    -branched, not linear
25
Q

What is Charles Darwins definition of EVOLUTION?

A

evolution to be descent with modification
-species are descendants of an ancestral species that were different from the species we see today

evolution is both a pattern and a process
pattern: scientific evidence
process: natural observed changes

26
Q

What was Aristotles early ideology?

A

Aristotle (384-322 BCE) saw species as unchanging/ fixed
-scale naturae (scale of nature)
-basis of Old Testament, life is permanent and perfect

27
Q

What was Carolus Linnaeus early ideology?

A

Carolus Linnaeus (1707-1778) classified life according to their similarities
-Linnaean classification of taxonomy
-nested classification compared to Scale Naturae
-described based on pattern of their creation (what they looked like)

28
Q

What were Darwins theories influenced by?

A

1.Fossils
-remains of traces of organisms from the past
-contained within rock layers called strata

  1. Slow and Subtle processes were changing organisms over time
29
Q

What was Georges Cuvier’s idea?

A

(1769-1832) notes older strata had different species than newer strata
-speculated that each stratum represented a single catastrophic event leading to the extinction of that species

30
Q

What was James Hutton’s idea?

A

(1726-1797) proposed that Earth’s geological features were a result of gradual processes (erosion, valleys being formed by rivers)

31
Q

What was Charles Lyell’s idea?

A

(!797-1875) proposed that the same geological processes in the past were occurring in the present, at the same rate

(based off James Hutton’s idea)

32
Q

What did Jean-Baptiste de Lamarck propose?

A

(1744-1829) proposed the first hypothesized mechanism for evolution

-suggested: evolutionary change explains that patterns seen in the fossils and how certain organisms are found in certain environments

-suggested: (1809 year Darwin was born)
there were multiple lines of descent.

-suggested: it was explained by use and disuse
-body parts that were needed became stronger and larger, body parts that were no longer needed deteriorated
ex. giraffes long necks

-suggested: inheritance of acquired characteristics
could be passed too offspring

suggested: organisms had a nature need to become more complex

33
Q

What was Darwins observation of adaptations?

A

Galapagos Islands
-darwin’s finches had different beak size and shapes based on environment and food sources

34
Q

What is natural selection?

A

where individuals that have certain inherited traits tend to survive better and reproduce due to those traits

NOTES TO REMEMBER:
1. individuals do not evolve, populations do
2. traits must be heritable and vary within a population for selection to occur
3. favourable traits depend on the context of the environment; evolution is not goal directed

35
Q

What is a common ancestor?

A

similar organisms that share a common ancestor from which they formed

36
Q

Diverse environment means diverse selective pressures, what do they lead to?

A
  1. leads to diverse adaptation to the environment
  2. lead to new divergent species
37
Q

What is Adaptive Radiation?

A

a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges or opens new environmental niches

38
Q

What do phylogenetic trees show?

A
  1. dedicated are the evolutionary relationships of vertebrates
  2. all organisms here have been evolving for the same amount of time
39
Q

What is Artificial Selection?

A

Darwin notes that humans have modified other species by selective breeding with desire traits

-trait must be variable in the species and heritable

40
Q

What factor provides selective pressure?

A

the environment
-takes a LONG time
-different population adapt to their environments and eventually become separate species

41
Q

What is Relative Fitness?

A

Contribution an individual makes to the gene pool of the next generation relative to other individuals in that population
-reproductive success of an individual
-better term for “survival of the fittest”

examples:
-no genetic disorder, no disease, surviving environmental condition, not getting eaten, ability to attract a mate

42
Q

Natural Selection cannot make a “perfect” organism, why?

A
  1. selection can only act on existing variations
    -favours only fittest variants from phenotypes available
    -may not be the best trait for an environment
  2. Evolution is limited by historical constraints
    -each species has a leafy of “descent with modification” from ancestral forms
    -evolution doesn’t start ‘fresh’, but modifies previous ones and adapts to existing conditions
  3. Adaptations are often compromises

BIOL 1020 FINAL (5 decks)

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