- (Plants) - Study Q's 1 - Evolution & Natural Selection

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1. What is evolution?

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Descent with modification.

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2. Define descent and indicate what is "modified."

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Descent is the origins of new organism from pre existing ones through the transfer of genetic material (DNA) generation after generation. Deoxyribonucleic acid is being modified.

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3. What is a lineage and what does it "involve?"

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A linage is a sequence of ancestors (parents) and descendents (offspring). It involves the transfer of genetic material through space and time.

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4. What is the unit of evolution?

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DNA.

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5. What is speciation?

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Speciation is the origins of new species from pre existing species.

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6. How is it that all life is connected by descent?

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Since all living organisms have a common ancestor sometime along the time of their existence and DNA get transferred with few alterations, therefore all lie is connected by a descent.

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7. What is systematics?

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Systematics is the field of biology that deals with the diversity and evolutionary history of life.

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8. What are the 4 components of taxonomy?

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- Description
- Identification
- Nomenclature
- Classification

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9. What is the emphasis or goal of systematics?

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The emphasis of systematics is on evolutionary history (phylogeny) of life. This is accomplished by using all types of evidence.

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10. What is the definition of classification?

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Classification is putting things e.g., life, into some type of order.

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12. What is a phylogenetic classification and what is its advantage?

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A phylogenetic classification is a classification based on known (inferred) evolutionary history. Its advantage is that it is a classification that reflects pattern of evolution and it is not ambiguous.

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13. What is a cladogram (phylogenetic tree)?

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A cladogram (phylogenetic tree) is a representation of history of life.

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14. What do the lines of a cladogram represent? the branching (divergence) of lines?

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The lines in the cladogram represent taxa and the branching (divergence) of lines represents a clade or a lineage.

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15. What is an apomorphy?

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Apomorphy is a new derived feature on a cladogram (phylogenetic tree).

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16. Why are taxa that share apomorphies grouped together?

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Taxa that share apomorphies are grouped together because is the result of evolution and also because the ones that are grouped together underwent some evolutionary history and should be grouped together.

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17. What is homology? Give an example.

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Homology is the similarity resulting from a common ancestor. E.g., the forelimb bones of a bat (wing), bird (wing), and human hand.

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11. What is a phenetic classification and what is its disadvantage?

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- A phenetic classification is a classification based on over all similarity. Organisms most similar are classified more closely together. The problem with classification is that it can be arbitrary.

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18. What is homoplasy and what are the two types of homoplasy (and an example of each)?

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- Homoplasy is a similarity not due to common ancestry.

A. Reversal: apomorphic (new) feature resembles ancestral (old) feature. E.g., loss of legs in snakes.

B. Convergence/parallelism: Similar, new features evolve independently of each other. E.g., the wings of two similar species in different continents evolved independently to serve as a tool for survival in different environmental conditions.

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19. What is a monophyletic group?

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- A monophyletic group is a group consisting of common ancestor plus all descendents of that common ancestor.

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21. What is the definition of phylogenetic "relationship?"

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A phylogenetic relationship is a recency of common ancestry. i.e., taxa sharing a common ancestor more recent in time are more closely related than those sharing a common ancestor more distant in time.

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22. Why are fish more closely related to human than to sharks?

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Fish is closely more related to humans than sharks because humans and fish share an earlier common ancestor than the one between fish and sharks.

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23. What is a paraphyletic group and why are they disadvantageous?

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A paraphyletic group consists of a common ancestor but not all descendents. Their disadvantage is that they tend to leave part of the history of evolution out when drawn on a cladogram.

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24. Name a common, past example of a paraphyletic group. How has this group been redefined to be monophyletic?

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- Reptilia (paraphyletic) included turtles, lizards and snakes, and crocodiles.
Reptilia (monophyletic) include all of the above including birds.

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25. How is the questions "did humans evolve from apes" somewhat confusing?

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It is confusing because humans are apes. Humans did not evolve from apes because they are apes.

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26. Why is systematics important and considered by some to be the foundation of biology?

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a. It is the basis fo classification of life:
b. Gives insight into biological processes, speciation processes, and adaptation to environment.
c. Can be aesthetically/intellectually pleasing.

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27. What two men are given credit for the notion of natural selection?

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Charles Darwin and Alfred Russell Wallace.

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28. Who wrote Origin of the Species and when?

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Charles Darwin wrote the Origin of Species in 1859.

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29. What were the two major accomplishments in Origin of the Species?

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a. provided, reviewed evidence for evolution.

b. provided a mechanism for evolution and natural selection.

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30. How was the fossil record evidence for evolution?

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The fossil record was evidence for evolution because it showed that there is homology (similarity due to common ancestry) which indicated that evolution is at work.

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31. Cite evidence from comparative anatomy, developmental similarity, and vestigial organs for evolution.

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a. Comparative Anatomy: Hand of humans, wing of a bat, and hand of a whale are all very similar to one another in term of forelimb structure.

b. Developmental similarity: chick embryo and human embryo share a similar post anal tale and pharyngeal pouches.

c. Vestigial organs: third molars, rudimentary ear muscles and vermiform appendix.

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32. How did Darwin redefine the word homology?

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Charles Darwin redefined the word homology by showing the similarity that is shown as a result of common ancestry is non-randomly picked by natural selection.

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33. Cite 3 observations/facts that are the basis for evolution by natural selection.

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a. Individuals of species vary from each other.

b. Some features are inherited.

c. More organisms are produced that can survive = “struggle for existence”.

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34. Thoroughly and completely (and clearly) define natural selection.

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Features that result in increased survivorship and reproduction will tend to be passed on to offspring in next generation.

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35. Why is natural selection differential?

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Natural selection is differential because those features that result in an increase in survivorship and reproduction ability will be passed on to the nest generation more.

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36. How is natural selection a non-random process?

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It is a non-random process because it is directed by survivorship and reproductive ability.

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37. What is the definition of fitness?

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Fitness is a measure of the relative contribution of a given genotype to the nest generation.

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38. What are two definitions of adaptation?

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a. a feature that provides a particular function for an organism.

b. a feature that results in an increase in fitness (survival and reproductive ability).

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39. Name some types of adaptations.

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Morphological adaptations:

a. Camouflage = protective resemblance.

b. Warning coloration = Poisonous frog.

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40. What is mimicry and how is it an adaptation?

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Mimicry is a deceptive resemblance. It is an adaptation because for example a Hawkmoth Larva mimics a snake to scare off predators, which will increase its level of survival.

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41. What is symbiosis?

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Is the process of two species living in close contact with each other.

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42. Name the type of symbiosis in which the host is harmed. ... in which both species benefit.

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a. Parasitism = the host is harmed.

b. Mutualism = both species benefit.

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43. What is co-evolution / co-adaptation?

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is two species, each living due to selective pressures from the other.

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44. What is a selective pressure?

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It is an agent or a causative force that results in selection.

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45. What is the selective pressure for dark skin in humans? for light skin? How does the environment influence this?

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The selective pressure for dark skin color in humans is UV radiation. The selective pressure for light skin color in humans is vitamin D synthesis. The environment influences this by providing presence of sun all year long in Africa for example for the dark skin. For the light skin, the environment provides light sun to allow the light skin to make vitamin D.

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46. What is genetic drift and how can it be promoted?

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Genetic Drift is the change of a genotype solely by a chance effect. It can be promoted by:

a. Population Bottle Neck = drastic reduction in population size.

b. Founder Effect = isolated colonies founded by small number of individuals.

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47. In summary, what are the two major mechanisms of evolution?

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The two major mechanisms for evolution are natural selection and genetic drift.

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48. How is selection dependent on the environment?

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If the environment changes, then the selection has to change because it has to pick characteristics that are capable of surviving in the new environment.

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49. Define and give an example of stabilizing selection, directional selection, and disruptive selection.

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a. Stabilizing Selection = selection against the two extremes in a population. E.g., birth weight in humans and clutch size in birds.

b. Directional Selection = selection for one extreme in a population against the other extreme. E.g. pesticide resistance in insects and antibiotic resistance in bacteria.
c. Disruptive Selection = selection for the two extremes in a population against the average forms. E.g. limpets with two color forms; light and dark in mosaic environments. Flies on two hosts; apple and hawthorn.

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50. What is sexual selection?

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It is a selection resulting in greater reproductive fitness in certain individuals of one sex.

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51. What are two types / aspects of sexual selection?

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Competition between members of one sex (males usually)

Preference by one sex for features of the other sex, usually female choice.

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52. How does sexual selection involve a balance between survivorship and reproduction?

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Sexual selection involves the reduction of survivorship while at the same time the increase of reproduction potential. This means that if for example a male get picked by a female, it will increase its reproductive potential, however, it will decrease its survivorship because it will not be hundred percent fir to its environment.