BIOL 2400 Chapter Notes - Chapter 1: Mutation, Genetic Drift, Reassortment

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5 Dec 2013

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Biological evolution any change in the inherited traits of a population to the next. Whales and dolphins are collectively known as cetaceans. Whales and fish lineages, evolving independently, converged on body forms that are superficially similar. Lineage a chain of ancestors and their descendants, referring to a single population, an entire species, or species descending from a common ancestor. Convergent evolution the independent origin of similar traits in separate lineages. Ambulocetus was a fossil whale that had legs. This animal had traits that were intermediate between modern whales and their terrestrial ancestors. Homologous characteristics that are similar in two or more species because they are inherited from a common ancestor. Synapomorphy is a derived form of a trait that is shared by a group of related species. The chemistry of fossil whales documents a transition from land to estuaries to the open ocean. The same transition documented in the changing shape of their skeletons.

Related Questions

1. Which of the following is NOT an example of evolution?

(a) Beak size in a population of birds becomes larger from onegeneration to the next

because larger beaked birds had higher reproductive success andpassed the trait to

their offspring

(b) Over long periods of time whales gradually lost theirhindlimbs

oxygen levels

(d) All of the above are examples of evolution

2. Jean-Baptiste Lamarck proposed:

(a) bacteria represent some of the youngest species on earth

(b) organisms can adapt to their environment

(d) all of the above

(e) none of the above

3. Carlos Linnaeus:

(a) devised a system of taxonomy that is still used today

(b) accepted the idea that most of lifeï¿½s diversity arosethrough the process of evolution

(d) a and b are correct

(e) a and c are correct

4. On what point(s) would Charles Darwin and Jean-BaptisteLamarck have agreed:

(a) adaptation occurs when individuals change to adapt to theirenvironment

(b) life is spontaneously generated all the time

(d) simple organisms have existed for a shorter period of timethan complex organisms

(e) they would have disagreed on all of these points

5. Several scientists have argued that life likely existed asfar back as 3.7 billion years ago. They base this claim on:

(a) the presence of biomarkers in rocks of that age

(b) fossils of stromatolites in rocks of that age

(d) the presence of tiny blobs of mineral-rich fluids in rocksof that age

6. The earliest generally accepted fossils of living organismsare:

(a) yeasts

(b) stromatolites

(d) carbon isotopes

7. The transition of from single-celled to multi-celledorganisms:

(a) happened once

(b) happened on multiple occasions

(d) a and c are correct

(e) b and c are correct

8. The earliest animal fossils appear similar to modern day:

(a) sponges

(b) archaea

(d) jellyfish

9. Tetrapods include:

(a) organisms descended from ancestors with four limbs

(b) birds

(d) all of the above

10. Based on current fossil evidence:

(a) whales were likely fully aquatic before they evolvedpeg-like teeth or baleen

(b) evolution of baleen forced whales to become fullyaquatic

mammals

(d) a and c are correct

(e) b and c are correct

I'm having trouble simplifying this 6 question paper. Pleaserewrite this then post in comments. thanks! just 1-5 senstences perquestion please. please!

1.Among systems for study of macro evolutionary change (e.g.,major change in anatomy, moving from water to land or vice versa,acquisition of flight, etc.), the cetaceans have become the 'posterchild'. Explain why cetaceans are a better system in which to studyevolutionary transitions than each of the following vertebrategroups:

Cetaceans have primitive taxa thatrecords sequences of change at three critical phases:

-Initial aquatic specialization

-Evolution of filter feeding withbaleen

-Derivation of echolaction.

Divergence times in cetaceans areconducive to detection of positive selection and inactive loci.Evolutionary splits in cetacea are deep enough to provide adequatechange for statistically robust analyses of molecular evolution butare not so deep that substitution patterns are saturated andrecognition of pseudogenes is hindered.

They have an impressive fossilrecord.

Whole genomes for both cetaceans andterrestrial cetartiodactyles can illuminate transitions andcandidate loci associated with aquatic features and degenerativeevolution have been characterized by several research groups.

turtles: highly derived taxa but areancient clades and more difficult to study from a molecularperspective.

manatees: The extant diversity ofaquatic manatees is limited.

bats: have a poor fossil record.

pterosaurs (ancient winged reptiles):Lack genetic Data.

2. What is myoglobin?

A myoglobin is a small 153-amino acidprotein that is the primary carrier and storage center of oxygen inmuscle.

Explain why increased diving ability should be correlated withspecific types of replacement mutations of the gene encoding theprotein myoglobin.

Amino acid replacement that increasedcharge occurred overwhelmingly in lineages of extreme divers withsemiaquatic or aquatic lifestyles. The greatest increase in chargeoccurred independently in cetaceans, pinnipeds, and the bever, allof which share at least two convergent amino acid replacementswithin each lineage.

What specific kinds of amino acid replacements are favored bypositive selection when increased diving ability is favored?

High net surface charge enableselectrostatic repulsion that might reduce deleterious selfassociation of myoglobin molecules; protein folding stability couldhave a similar impact by limiting the percentage of misfoldedmolecules at high expression levels.

Explain how the maximum dive capability of an extinct whalespecies can be estimated.

By combining body mass with inferredconcentration of myoglobin based on net surface charge they wereable to estimate the maximum dive times of extinct cetaceans.

3. What is the general function of the protein prestin?

Is involved in conferringelectromotility to the outer hair cells of the cochlea, enablingsensitive to sound by driving the cochlear amplifier.

Explain why a phylogenetic treereconstructed using the characters of prestin amino acid sequencesshowed at first that the whales form a subgroup within thebats!

A phylogenetic analysis of prestinamino acid sequences supported a tree in which some odontocetecetaceans were nested within bats with high support, despitephylogenetic analsysts of nucleotides sequences favoring a moredistant relations.

This pattern was driven by convergentamino acid changes in that were shared between toothed whales andecholocating bats.

4. Relative to terrestrial mammals, what changes occurred togive deep diving cetaceans 'rod monochromacy'?

Rod monochromancy is unique amongmammals due to extreme adaptation to low light levels.

What is the advantage of rod monochromacy?

Allows you to see in low lightlevels.

Why does it make sense that rhodopsins of cetaceans are shiftedfrom red (low energy) to blue (high energy) sensitivity?

The mechanisms underlying the spectraltuning of two of these blue-shifted pigments have recently beenelucidated and depend on three amino acid substitutions(⁸³Asn, ²⁹²Ser, and ²⁹⁹Ser) indolphin rhodopsin, but only one amino acid substitution(³⁰⁸Ser) in the dolphin long-wavelength-sensitivepigment. The objective of this study was to investigate themolecular basis for changes in the spectral sensitivity of rodvisual pigments from seven distantly related marine mammals. Theresults show a relationship between blue-shifted rhodopsins([lambda]_max [less-than-or-equal] 490 nm), deep-divingforaging behavior, and the substitutions ⁸³Asn and²⁹²Ser. Species that forage primarily near the surfacein coastal habitats have a rhodopsin with a [lambda]_maxsimilar to that of terrestrial mammals (500 nm) and possess thesubstitutions ⁸³Asp and ²⁹²Ala, identical torhodopsins from terrestrial mammals.

5. What is the function of the protein ameloblastin?

Is an enamel matrix protein. Theprotein that encodes AMBN gene. Allows growth activity andstructure of the tooth enamel.

Characterize the specific nucleotide sequence and functionaldifferences in ameloblastin genes between baleen whales versusother mammals.

Baleen whale a toothed whale and moredistantly related mammals with single base pair frameshiftinsertion in the baleen whale AMBN pseudogene. Clear cut molecularsignature of a shared signature of shared aquatic ancestry forhippos and whales is currently lacking. Loci related to underwatercision, deep diving and lung surfactant do not show evidence ofmolecular adapation in the common ancestor of these taxa.

6. What are the two main general categories of convergentevolution described in cetaceans and other vertebrates?

Auditory genes. Bats and odontecetshave many similar capabilities with regards to high frequency soundperception.

Selection has driven the independentloss of both OPNI1SQ and OPN1LW in deep diving cetaceans tooptimize visual acuity at depth and at night.

Loss of functional TAS1R genes alsooccurred independently in Otariidae (sea lions) and many carnivorsmammals convergently lack the fuctional sugar taste perception geneTAS1R2

Based on these studies why is it important to use neutral ornearly neutral characters in phylogenetic analyses wheneverpossible?

Comparison amobg a broader taxonomicsample of geneoms can reveal learge suits of genes that haveundergone convergent recruitment and subsittuions among multipleclades of aquatic tetrapods.

orangebear508

The Cambrian explosion is a prime example of ________________.

		mass extinction
		evolutionary stasis
		a large meteor impact
		adaptive radiation

1 points

QUESTION 2

Most animals are viviparous.

True

False

1 points

QUESTION 3

The first phylum with ganglia in their nervous system are the ________________________.

		Mollusca
		Nematoda
		Bivalvia
		Platyhelminthes

1 points

QUESTION 4

The last common ancestor of all animals was probably a _____________________.

		a unicellular worm
		multicellular algae
		flagellated protist
		multicellular fungus

1 points

QUESTION 5

You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile by use of many short extensions of the cytoplasm. It has well-developed organelles and two nuclei, one large, one small. The organism is most likely to be a ______________.

		foraminifera
		radiolarian
		ciliate
		flagellate

1 points

QUESTION 6

Which of the following organisms would you expect to have the largest surface-area-to-volume ratio? Assume that all of the following are the same total length.

		A mollusc
		A nematode
		A platyhelminth
		Not enough information to determine.

1 points

QUESTION 7

If the animal is a hermaphrodite, it is said to be _______________.

		dioecious
		eutelic
		monoecious
		trioecious

1 points

QUESTION 8

A terrestrial animal species is discovered with the following larval characteristics: exoskeleton, system of tubes for gas exchange and segmentation. A knowledgeable zoologist should predict that the adults of this species would also feature ____________.

		eight legs
		two pairs of antennae
		a sessile lifecycle
		an open circulatory system

1 points

QUESTION 9

The Phylum Echinodermata exhibits metamerism.

True

False

1 points

QUESTION 10

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that _____.

		a larger volume-to-surface area ratio is adaptive in many mammals
		evolution generally progresses toward some goal
		evolution tends toward increased complexity or increased size
		in particular environments, similar adaptations can be beneficial to more than one species

1 points

QUESTION 11

Suppose you are a researcher fro a pest-control company and you develop a chemical that inhibits the develpment of an embryonic mosquito's endodermal cells. Which of the following would cause the pesticide to work?

		The mosquito would develop a weak exoskeleton, making it easy prey.
		The mosquito's gut would not function properly and it would starve.
		The mosquito would not have a properly functioning muscular system.
		Nothing would happen and your experiment would be a failure.

1 points

QUESTION 12

Holometabolis refers to complete metamorphosis.

True

False

1 points

QUESTION 13

Which of these conditions are always true of populations evolving due to natural selection?
Condition 1: The population must vary in traits that are heritable.
Condition 2: Some heritable traits must increase reproductive success.
Condition 3: Individuals pass on most traits that they acquire during their lifetime.

		Condition 1 only
		Condition 2 only
		Conditions 1 and 2
		Conditions 2 and 3

1 points

QUESTION 14

Scientific theories _____. 22.3

		are nearly the same things as hypotheses
		are supported by, and make sense of, many observations
		cannot be tested because the described events occurred only once
		are predictions of future events

1 points

QUESTION 15

The evolution of animal species and their diversity is a result of the evolution of new and different ways to _______________.

		reproduce
		arrange their cells into tissues
		become symmetrical
		form an embyro and establish a basic body plan

BIOL 2400 Chapter Notes - Chapter 1: Mutation, Genetic Drift, Reassortment

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