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Biol 221 > Pre Midterm I > Flashcards

Pre Midterm I Flashcards

Understand definitions of phylogenies, evolution, etc.

1
Q

What are subfossils vs coprolites?

A

Subfossils are not old enough to be considered true fossils
Coprolites are fossilized feces

Copros comes from kopros meaning feces

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2
Q

Which kingdom of life evolved first?

A

Bacteria, then likely archaebacteria

Note: Bacteria are generally haploids

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3
Q

Define supposition

A

Dating fossils based on surrounding rock layers

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4
Q

Order the eons of geologic time

A
  1. Hadeon Eon
  2. Archeon Eon
  3. Proterozoic eon (oxygen revolution) (ends with Cambrian)
  4. Phanerozic eon (current)
    • paleozoic
    • mesozoic
    • cenozoic (current)
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5
Q

Order the key events of the phanerzoic eon

A
  1. Earliest chordate fossils
  2. Oldest trackways
  3. Land plant fossils
  4. Oldest land vertebrates
  5. Dinosaurs
  6. Common mammalian ancestor
  7. Birds
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6
Q

About how long ago did eukaryotes come into existence?

A

~ 1.8 bya

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7
Q

What were the first animals, and why do we consider them animals?

A
  1. Sponges
  2. Cholesterol like-biomarker
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8
Q

What are the key features of the Cambrian explosion?

A
  1. Bilateral symmetry, segmentation
  2. Increased body size, complexity
  3. Hard body parts
  4. First Chordates

Likely caused by increased oxygen, predation, evolutionary innovation

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9
Q

When did the first land plants evolve?

A

Late ordovician or Silurian ~ 450 mya

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9
Q

Characterize the end of the Devonian period

A

Ferns, horse tails and emergence of first seed plants

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10
Q

Approx how old are humans?

A

Homo sapiens are around 200k years old

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10
Q

DELETE

A
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10
Q

DELETE

A
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11
Q

Define and give an example of a synapomorphy, symplesiomorphy.

A

Synapomorphy: Shared derived trait from most recent common ancestor of taxa
example: Body hair of mammals
Symplesiomorphy: Ancestral trait
example: Body hair for primates, bipedalism of hominins

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12
Q

Define and give an example of autopomorphy

A

A derived trait UNIQUE to a single taxa

eg Bird feathers

“self form”

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13
Q

Define in your own words, the differences between* homoplasy* and homology, provide an example for each.

A

Homoloplasy: “Same form” is an analogous trait, arise from convergent evolution
example: Bird and bat wings
Homology: “Same relation” is a trait arisen from a common ancestor
eg Forearm structure in whales, cats, bats, humans.

The hope is the most parsimonius clado will expose homoplasies

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14
Q

What is the difference between synapomorphy and homology.

A

A synapomorphy is a shared trait from most recent common ancestor, this may include present or lack of presence of anatomical feature
A homology is an anatomical feature present that arises from most recent common ancestor

  • Every homology is a synapomorphy, but not every synapomorphy is a homology
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15
Q

What is the difference between a cladogram and a phylogram?

A

Cladogram does not depict passage of time, a phylogram depicts passage of time, or # of evolutionary changes

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16
Q

DELETE

A
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17
Q

DELETE

A
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18
Q

True or False:
According to Biol221:
A majority of mutations are harmless.

A

False
Also:Recall all mutations are equally likely, and most are not inherited

Analogy: When writing an essay, how often are typos beneficial?

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19
Q

Which nucleotides are purines?

DNA

A

Adenine and guanine

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20
Q

Which nucleotides are pyramidines?

i

A

Thymine and cytosine, and uracil

21
Q

Which nucleotides pair together?

in DNA

A

Pyramidine and a purine,
eg AT and GC

22
Q

What is the purpose of wrapping DNA in histones?

A

Protection
Limiting access to transcription (regulation)

23
Q

True or False:
Transcription requires two template strands

A

False, only one is used

24
Q

Define isoforms

A

Similar proteins, that occur because of alternative splicing of mRNA

25
Q

What is the difference between a missense mutation and a nonsense mutation?

A

Missense: Encoding of wrong amino acid
Nonsense: Premature encoding of stop codon

26
Q

What are the types of point mutations?
Will they necessarily have an effect on protein structure or function?

A

Transition: Purine replaced with purine, or pyramidine with pyramidine
ie AG/ with AG or CT with CT
Transversions: Purine replaced with pyramidine, or vice versa

2) possibly, synonmous = silent (no effect)

Synonymous means “same meaning”

27
Q

What kind of mutation may cause a frame shift

Hint: Recall we went over 5 types of mutations

A

Definetly indels and duplications

28
Q

What is a translocation mutation?

A

Non homolgous chromosomes fuse

29
Q

What are transposable elements?

A

Genes, products of ancient viral infection.

30
Q

Explain the difference between mono, para, and poly phyla

A

Mono: contains all descendants of common ancestor
Paraphyla: Contains some descendants
Polyphyla: Taxa do not share common ancestor

31
Q

When did hard body parts first appear in animals?

A

Cambrian explosion

32
Q

Characterize the Archaeon period

A

~ 3.8 t0 2.5 bya
Life is limited to the ocean

33
Q

What is the difference between phylogenetics and taxonomy?

A

Taxonomy is the classifcation of organisms, phylogenetics ensures classification reflects evolutionary relationships

34
Q

What are pseudogenes?

A

Ancient genes that lack a promoter, they are evolutionary artifacts

35
Q

True or False:
Phenotypes cannot change in one’s lifetime.

A

False.
A phenotype could definitely change in a life time

Note: Phenotypes are not inherited, selection acts on phenotype not geno

36
Q

What is the difference between polyphenism and genotypic plasticity?

A

Polyphenism is a special case of genetic plasticity, which involes more than one discrete phenotype, which may arise from single genotype,

plasticity refers to a spectrum

As a reminder most traits are not Mendelian

37
Q

What is an allele?

A

Variation in a genetic sequence found in the same loci between different homologous chromosomes. DIploidic organisms will have just 2 alleles, though many can exist in a population.

38
Q

Where is the codon located?

A

On the mRNA not DNA

39
Q

When is carbon dating a good idea?

A

For specimens < 50k years old

40
Q

The earliest primate fossils show up around which time period?

A

In the cenozoic era

40
Q

Who developed the first “real” trees, ie with time scales?

A

Ernst Haekel

41
Q

What are the most common types of mutations? and least common?

A

Most: Point mutation
Least: change of # of chromosomes

42
Q

What is Mendel’s Law of Segregation

A

each gamete recieves just one allele

43
Q

What is Mendel’s Law of Segregation

A

Each gamete gets one allele

44
Q

Give an example of a polyphenism

A

Dung beetle horns are either large or small depending on nutrition during development, aphid wings are either small or large depending on day length and nutrition during development

45
Q

When did multicellularity arise?

A

From 1.6 to 2.1 bya (potentially)

Note: Similar time frame to Eukaryotes

46
Q

Does diversity always reflect evolution?

A

Evolution is change in allelic frequency in population, so if diversity is not a result of this, then no.

47
Q

What is the role of the outgroup?

A

A species suspected to have split off prior to diversification event, helps root the tree

48
Q

True or False:
Mutations are adaptively directed

A

False, mutations are not driven by the environment, the benefit/harm of mutations are driven by the environment

49
Q

Why don’t most traits follow Mendelian Inheritance?

ie Why don’t phenotypes match Mendelelian predictions?

A
  1. More than 2 population alleles exist
  2. Influence of other genes
  3. Influence of environment
50
Q

What causes traits to be continuous?

A

Polygenetic inheritance,
ie many genes contribute to same trait

51
Q

True or False:
Environmental conditions will NEVER have a greater impact on phenotype, than the Genotype

A

False:
They often do have greater impact than genotype

Biol 221 (3 decks)

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