BIOL 142 Chapter Notes - Chapter 22.1: Special Creation, Natural Selection

In the passages below, Darwin and Wallace both clearly define what a species is based on their observations of the natural world. They then provide explanations for how new species arise.

Excerpt from “The Origin of Species and Genera (S322: 1880), January 1880 issue of Nineteenth Century,” by Alfred R. Wallace ... A species may be defined as a group of individuals of animals or plants which breed together freely and reproduce their like; whence it follows that all the individuals of a species, now living or which have lived, have descended from a few common ancestors, or perhaps from a single pair. Thus all horses, whether Shetland ponies, racers, or cart-horses, form one species, because they freely breed together, and are known to have all descended from a common stock. By the same test the common ass, the kiang, the quagga, and the zebra, are each shown to be distinct species; for though sometimes two of these species will breed together, they do not do so freely, they do not reproduce their like but an intermediate form called a mule, and these mules are not capable of reproducing their kind, as are the offspring of any pairs of a single species.

Excerpt from “On the Origin of Species,” by Charles Darwin, 1859 ... So with natural species, if we look to forms very distinct, for instance to the horse and tapir, we have no reason to suppose that links ever existed directly intermediate between them, but between each and an unknown common parent. The common parent will have had in its whole organisation much general resemblance to the tapir and to the horse; but in some points of structure may have differed considerably from both, even perhaps more than they differ from each other. Hence in all such cases, we should be unable to recognise the parent-form of any two or more species, even if we closely compared the structure of the parent with that of its modified descendants, unless at the same time we had a nearly perfect chain of the intermediate links. ...

Excerpt from On the Origin of Species, Chapter 4, by Charles Darwin, 1859 ... On the view that each species has been independently created, I can see no explanation of this great fact in the classification of all organic beings; but, to the best of my judgment, it is explained through inheritance and the complex action of natural selection, entailing extinction and divergence of character, as we have seen illustrated in the diagram. ...

Question: From all these readings, is there evidence that both Darwin and Wallace independently formulated the theory of evolution by natural selection? Support your answer.

What exactly was Hooker's response to Darwin's, Origin of Species? Thank you for your help. I need help deciphering what his opinions truly were.

Hooker, J. D. 1859. [Review of] On the origin of species. Gardeners' Chronicle (31 December): 1052. Part 1.

From the above expressions it will be inferred that we have risen from the perusal of Mr. DARWIN'S book much impressed with its importance, and have moreover found it to be so dependent on the phenomena of horticultural operations, for its facts and results, and so full of experiments that may be repeated and discussed by intelligent gardeners, and of ideas that may sooner fructify in their minds than in those of any other class of naturalists, that we shall be doing them (and we hope also science) a service by dwelling in some detail upon its contents. Thus much we may premise, that it is a book teeming with deep thoughts on numberless simple and complex phenomena of life; that its premises in almost all cases appear to be correct; that its reasoning is apparently close and sound, its style clear, and we need hardly add its subject and manner equally attractive and agreeable; it is also a perfectly ingenuous book, bold in expressions as in thought where the author adduces what he considers clear evidence in his favour, frank in the statement of objections to the hypotheses or conclusions founded on its facts and reasonings; and uniformly courteous to antagonistic doctrines. In fine, whatever may be thought of Mr. DARWIN'S ultimate conclusions, it cannot be denied that it would be difficult in the whole range of the literature of science to find a book so exclusively devoted to the development of theoretical inquiries, which at the same time is throughout so full of conscientious care, so fair in argument, and so considerate in tone. . . . Hitherto most [naturalists] have, as we have already observed, contented themselves with the hypothesis that they were independently created, and the minority have clung to the only other explanation hitherto conceived, that they have all been created by variation from a single first-created living organism, or a few such. Now it must be borne in mind that both these views are mere hypotheses in a scientific point of view; neither has any inherent or prescriptive right to a preference in the mind of the impartial inquirer; but the most superficial observation will show that the hypothesis of original creations is incapable of absolute proof, except the operation be witnessed by credible naturalists, and can only be supported by facts that are either not conclusive against the opposite doctrine, or may be regarded as equally favourable to it; and this hypothesis is hence placed at a disadvantage in comparison with that of the creation of species by variation, which takes its stand on the familiar fact that species do depart from the likeness of their progenitors, both in a wild and domestic state. On the other hand the hypothesis of creation by variation labours under the disadvantage of being founded upon a series of phenomena, the action of each of which individually, as explained by Mr. DARWIN, would appear to prevent the possibility of species retaining their characters for any length of time, and it therefore appears at first sight opposed to the undisputed fact, that many hundreds of animals and plants have transmitted their characters unchanged (or nearly so) through countless generations, and covered, even within the historic period, many square miles of country each with millions of its exact counterpart. To explain this anomaly and to raise this hypothesis of creations by variation to the rank of a scientific theory, is the object of Mr. DARWIN'S book, and to do this he has endeavoured to invent and prove such an intelligible rationale of the operation of variation, as will account for many species having been developed from a few in strict adaptation to existing conditions, and to show good cause how these apparently fleeting changelings may by the operation of natural laws be so far fixed as to reconcile both the naturalist and the common observer to the idea, that what in all his experience are immutable forms of life may have once worn another guise. The hypothesis itself is a very old one; it was, as all the world knows, strongly advocated by LAMARCK, and later still by the author of the "Vestiges of the Natural History of the Creation," but neither of these authors were able to suggest even a plausible method according to which Nature might have proceeded in producing suitable varieties, getting rid of intermediate forms, and giving a temporary stability to such as are recognised as species by all observers. Mr. DARWIN has been more successful, though whether completely so or not the future alone can show. We shall proceed to examine his method in another article.

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 Jr’s 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.

“Fitness” in an evolutionary sense, refers to an individual’s:

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

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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 Darwin’s Four Postulates] (PDF1-3).

27. Who was Thomas Malthus? In what way(s) Malthus was influential for Darwin’s 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.