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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
What is the purpose of wrapping DNA in histones?
Protection Limiting access to transcription (regulation)
23
True or False: Transcription requires two template strands
False, only one is used
24
Define isoforms
Similar proteins, that occur because of **alternative splicing** of mRNA
25
What is the difference between a missense mutation and a nonsense mutation?
**Missense**: Encoding of wrong amino acid **Nonsense**: Premature encoding of **stop** codon
26
What are the types of point mutations? Will they necessarily have an effect on protein structure or function?
**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
What kind of mutation may cause a **frame shift** | Hint: Recall we went over 5 types of mutations
Definetly indels and duplications
28
What is a translocation mutation?
**Non** homolgous chromosomes **fuse**
29
What are transposable elements?
Genes, products of ancient viral infection.
30
Explain the difference between mono, para, and poly phyla
Mono: contains **all** descendants of common ancestor Paraphyla: Contains some descendants Polyphyla: Taxa do not share common ancestor
31
When did hard body parts first appear in animals?
Cambrian explosion
32
Characterize the Archaeon period
~ 3.8 t0 2.5 bya Life is limited to the ocean
33
What is the difference between phylogenetics and taxonomy?
**Taxonomy** is the **classifcation** of organisms, **phylogenetics** ensures classification reflects **evolutionary** **relationships**
34
What are pseudogenes?
Ancient genes that **lack** a **promoter**, they are evolutionary artifacts
35
True or False: Phenotypes cannot change in one's lifetime.
False. A phenotype could **definitely** change in a life time | Note: Phenotypes are not inherited, selection acts on phenotype not geno
36
What is the difference between polyphenism and genotypic plasticity?
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 ## Footnote As a reminder most traits are not Mendelian
37
What is an allele?
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
Where is the codon located?
On the mRNA not DNA
39
When is carbon dating a good idea?
For specimens < 50k years old
40
The earliest primate fossils show up around which time period?
In the **cenozoic** era
40
Who developed the first "real" trees, ie with time scales?
Ernst Haekel
41
What are the most common types of mutations? and least common?
Most: Point mutation Least: change of # of chromosomes
42
What is Mendel's Law of Segregation
each gamete recieves just one allele
43
What is Mendel's Law of Segregation
Each gamete gets one allele
44
Give an example of a polyphenism
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
When did multicellularity arise?
From 1.6 to 2.1 bya (potentially) | Note: Similar time frame to Eukaryotes
46
Does diversity always reflect evolution?
Evolution is change in allelic frequency in population, so if diversity is not a result of this, then no.
47
What is the role of the outgroup?
A species suspected to have split off prior to diversification event, helps root the tree
48
True or False: Mutations are adaptively directed
False, mutations are not driven by the environment, the benefit/harm of mutations are driven by the environment
49
Why don't most traits follow Mendelian Inheritance? | ie Why don't phenotypes match Mendelelian predictions?
1. More than 2 population alleles exist 2. Influence of other genes 3. Influence of environment
50
What causes traits to be continuous?
Polygenetic inheritance, ie many genes contribute to same trait
51
True or False: **Environmental** **conditions** will NEVER have a greater impact on phenotype, than the **Genotype**
False: They often do have **greater** impact than **genotype**

Biol 221 (3 decks)

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