Biology 1201A Lecture Notes - Lecture 6: Seedless Fruit, Aneuploidy, Fundamental Theorem Of Arithmetic

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14 Dec 2019

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Variation in heritable traits among individuals of a population. Many offspring are produced, more than can survive. Individuals whose traits allow them to better survive in their environment will leave more offspring. Over time, these traits become more common in the population. All organisms have descended from ancestors, with modification. Populations can become more different over time, resulting in new species. Modern synthesis - incorporating genes, dna it is our understanding of evolution. Other mechanisms have been described that can also result in evolution, e. g. , genetic drift. Took bacteriophages and radioactively labelled the proteins, or radioactively labelled the dna, and allowed the phages to replicate. Found out that the radioactively labelled dna was replicated and was found within the newly made phages. Majority of human cells are diplod (n=46) Human sperm and egg cells are haploid (n=23) 2 sets of each chromosome = homologous. Different versions of a gene are called alleles. Some organisms are polyploid (plants, protists, bacteria, archaea)

Related Questions

Excerpt from âOn the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection,â by Charles Darwin [Read July 1st, 1858].

To give an imaginary example from changes in progress on an
island:âlet the organisation of a canine animal which preyed
chiefly on rabbits, but sometimes on hares, become slightly plastic;
let these same changes cause the number of rabbits very slowly to
decrease, and the number of hares to increase; the effect of this
would be that the fox or dog would be driven to try to catch more
hares: his organisation, however, being slightly plastic, those
individuals with the lightest forms, longest limbs, and best eyesight,
let the difference be ever so small, would be slightly favoured, and
would tend to live longer, and to survive during that time of the year
when food was scarcest; they would also rear more young, which
would tend to inherit these slight peculiarities. The less fleet ones
would be rigidly destroyed. I can see no more reason to doubt that
these causes in a thousand generations would produce a marked
effect, and adapt the form of the fox or dog to the catching of hares
instead of rabbits, ... So would it be with plants under similar
circumstances. If the number of individuals of a species with plumed
seeds could be increased by greater powers of dissemination within
its own area (that is, if the check to increase fell chiefly on the seeds), those seeds which were provided with ever so little more down, would in the long run be most disseminated; hence a greater number of seeds thus formed would germinate, and would tend to produce plants inheriting the slightly better-adapted down.

Questions: 2 examples must be provided for each question

DarwinâNatural Selection

Species:

What trait varies within the species?

What is the selective pressure? (In other words, what causes some individuals to produce more offspring than others?)

How would the population change over time?

Excerpt from âOn the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection,â by Charles Darwin [Read July 1st, 1858]. To give an imaginary example from changes in progress on an island:âlet the organisation of a canine animal which preyed chiefly on rabbits, but sometimes on hares, become slightly plastic; let these same changes cause the number of rabbits very slowly to decrease, and the number of hares to increase; the effect of this would be that the fox or dog would be driven to try to catch more hares: his organisation, however, being slightly plastic, those individuals with the lightest forms, longest limbs, and best eyesight, let the difference be ever so small, would be slightly favoured, and would tend to live longer, and to survive during that time of the year when food was scarcest; they would also rear more young, which would tend to inherit these slight peculiarities. The less fleet ones would be rigidly destroyed. I can see no more reason to doubt that these causes in a thousand generations would produce a marked effect, and adapt the form of the fox or dog to the catching of hares instead of rabbits, ... So would it be with plants under similar circumstances. If the number of individuals of a species with plumed seeds could be increased by greater powers of dissemination within its own area (that is, if the check to increase fell chiefly on the seeds), those seeds which were provided with ever so little more down, would in the long run be most disseminated; hence a greater number of seeds thus formed would germinate, and would tend to produce plants inheriting the slightly better-adapted down.

2 examples must be provided for each question. One for each species.

DarwinâNatural Selection

Questions:

What are the two Species? What trait varies within the species?

What is the selective pressure? (In other words, what causes some individuals to produce more offspring than others?)

How would the population change over time?

Messenger RNA (mRNA)...

a) Is a structural part of a ribosome

b) Brings amino acids to DNA

c) Carries genetic information from the nucleus to the cytoplasm

d) Is a structural part of a chromosome

e) Initiates and directs chemical reactions

Mr. Potato is homozygous dominant (KK), his son, Potato Jr. is heterozygous (Kk). Based on this information, what are the possible genotypes for Mrs. Potato? (Hint: use a Punnet Square).

a) Her genotype is definitely kk

b) Her genotype is either Kk or kk

c) Her genotype is either KK or Kk

d) Her genotype is either KK, or Kk, or kk

e) Mr. Potato cannot be Potato Jrâs biological father

12. Homologous chromosomes:

a) Are members of different chromosome pairs

b) Are genetically identical

c) Carry genetic information that influences the same traits (same genes but probably different alleles)

d) Are only inherited from the mother

e) Are only inherited from the father.

âFitnessâ in an evolutionary sense, refers to an individualâs:

a) Strength

b) Reproductive success

c) Aggressiveness

d) Size

e) Age at death

The fact that individuals who possess favorable traits are more likely to survive and reproduce than those who possess less favorable traits is the basis for the theory of...

a) uniformitarianism.

b) natural selection.

c) the inheritance of acquired characteristics.

d) catastrophism.

e) the fixity of species.

Even with strong selection, genetic variation of a population can be maintained because:

a) Selection only affects one gene at a time.

b) The effects of many alleles are hidden from selection by the effects of other alleles

c) Mutation constantly adds new alleles at an extremely fast rate.

d) Populations always go extinct before their gene frequencies are dramatically altered.

e) Only a and c

Gene Flow is defined as the:
a) Production of new alleles
b) New musical group in which Adam Levine will be the leading vocalist
c) Exchange of genes between populations
d) differential reproductive success of individuals
e) Process by which a DNA base gets extracted out of the nucleus to initiate the process of protein synthesis.

The basic unit of DNA is a molecule called a: a) Nucleotide

b) Base
c) Thymine
d) Prokaryoticcell e) mRNA

How many bases code for one amino acid? a) one

b) two
c) it depends on what amino acid it is d) three
e) four

Hemophilia is a condition that affects: a) more females than males
b) more males than females
c) females and males equally

d) only children born prematurely
e) individuals with a missing portion of chromosome number 5

A clear example of directional selection is:
a) Darwin finches with deeper and thicker beaks associated to a severe drought b) Sickle cell anemia in regions in which Malaria is endemic
c) Achondroplasticdwarfism
d) Fly halteres becoming fully developed wings after modification of a hox gene e) all of the above

Meiosis is evolutionarily significant because:
a) New combination of alleles can arise through independent assortment and crossing over

22.

23.

24.

25.

26.

b) It is the mechanism by which body tissues are repaired
c) It creates somatic cells that are crucial for our body organs to maintain us alive d) It allows forensics to determine the cause of death of unidentified people
e) none of the above

Homologous chromosomes:

a) Are exact copies of each other and contain exactly the same genetic material
b) Are members of different chromosome pairs
c) Are only inherited from the father
d) carry genetic information that influences the same traits (the same genes), however, each of the homologous chromosomes can contain different versions of the same gene (different alleles).

e) carry genetic information that influences different traits because each of the homologous chromosomes contains completely different genes at very different loci

How many chromosome pairs occur in a normal human somatic cell?

a) 46 b) 23 c) 22 d) 24 e) 45

What is the scientific method? Use bullet points to describe the 4 major components.

How is a hypothesis different from a theory?

List the four major components (described during class) necessary for natural selection to occur [AKA Darwinâs Four Postulates] (PDF1-3).

27. Who was Thomas Malthus? In what way(s) Malthus was influential for Darwinâs Theory of Natural Selection? Hint: populations vs resources.

29. What amino acids are being coded for by the gene segment provided below? Nucleotide triplets and their corresponding amino acids are:
ACA= Cysteine; AAA=Phenylalanine; TGG=Threonine; CCT=Glycine; GAT=Leucine; ATA=Tyrosine; AGG=Serine; TCT=Arginine

a) Threonine, serine, glycine, tyrosine, leucine, phenylalanine, arginine, cysteine.

b) Tyrosine, leucine, glycine, threonine, arginine, threonine, serine, cysteine.

c) Arginine, cysteine, serine, glycine, threonine, leucine, phenylalanine, tyrosine.

d) Phenylalanine, leucine, tyrosine, glycine, serine, threonine, cysteine, arginine.

e) Phenylalanine, leucine, tyrosine, glycine, threonine, phenylalanine, arginine, serine.

Biology 1201A Lecture Notes - Lecture 6: Seedless Fruit, Aneuploidy, Fundamental Theorem Of Arithmetic

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