BIOL3044 Lecture Notes - Lecture 16: Queen'S Gambit Declined, Point Given, Elytron

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indigobat594

13 Nov 2021

School

Dalhousie University

Department

Biology

Course

BIOL3044

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Real life organisms are made up of multiple traits with multiple selection pressures it"s not just one trait: the traits may or may not be correlated with each other. When we deal with multiple traits, we have to think about distributions in multiple dimensions. One trait: a normal distribution: bell-shaped curve, frequency of most common trait is the peak, close to the average, extremely large and small traits are on either side, tend to be rare. Two traits: bivariate normal distribution: we can still have a normal distribution but in 2 dimensions. If we take any particular slice off of this 2d hill, it would look like one of the normal distributions. If we take different slices across the 2d distribution and put it together, we"ll get a hill in. No correlation between traits the hill is perfectly round, no tendency for one combination of traits to be more common than the other.

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Question 5

Which of the following is FALSE:

Natural selection has foresight, and can mold organisms in accordance with environments in the far future. This is why organisms have a good "fit" to their environments long after they have arisen through speciation.

Selection is an undirected process that can only ever work with the materials at hand.

Human beings have foresight because they possess brains that can think about possible outcomes and the consequences of actions. This is different to a process like natural selection.

The fact that natural selection has no foresight does not mean that it is incapable of producing beings that have foresight.

Question 6

The wings of bats, birds and flying insects are examples of:

Convergently evolved traits (at least in terms of their basic functionality).

Homologous traits.

Plesiomorphies.

None of the above.

Question 7

The effect of a trait depends on the environment because:

Organisms decide to change their behavior every so often to evade predators.

It is only ever in the context of an environment that these traits can exist, and whether they assist the organism or inhibit it will depend on the particularities of that environment in which it must interact.

Sexual selection will not tolerate wasteful and extravagant displays.

The environment is changing too fast for the organism to keep up with in terms of its conscious appreciation of it, so it must rely on its traits to do the work.

Question 8

Which of the following is TRUE:

Natural selection is not random; mutation is random; speciation is necessarily driven by natural selection.

Natural selection is not random; mutation is random; speciation is not necessarily driven by natural selection.

Natural selection is random; drift is random; speciation is not necessarily driven by natural selection.

Natural selection is not random; mutation is random; speciation must occur through the evolution of pre-zygotic barriers to mating.

Question 9

Heritability is:

The same as inheritance.

Another way of stating the degree to which a trait is genetic (for example, you could say that the color of your skin is "80 percent genetic and 20 percent environmental")

The proportion of variance of a trait in a population that is attributable to genetic variance in that population.

Present in populations, but not necessary for evolution by natural selection.

jadelocust741

Which statement about evolution by natural selection isfalse?

Natural selection allows organisms with higher fitness toreproduce more successfully.

Natural selection favors those traits that confer higherfitness in the environment.

Natural selection is a random change in characteristics of apopulation over generations.

Evolution by natural selection affects populations oforganisms, not individual organisms.

An organism's fitness depends on its _____.

ability to survive and reproduce

ability to swap genetic material with other organisms

physical size

ability to mutate

population

Consider the heavily armored stickleback fish population thatcolonized the lake. If all the individuals in that population weregenetically identical, what do you predict would happen when theycolonized the freshwater lake?

The population would increase, as it has increased foodresources.

The population would evolve through natural selection to bebetter adapted to its environment.

The population would decrease due to more juvenile fish beingeaten.

No answer text provided.

Which of the following are adaptations?

Thicker beaks on finches that allows them to eat large seeds,when large seeds are the most abundant.

Less armor on stickleback fish in freshwater that allows themto grow faster to avoid predation.

More armor on stickleback fish in the ocean that prevents themfrom being eaten by larger predators.

None of the above.

All of the above.

olivemink746

Many traits are affected by theenvironment, but also have a genetic component. How can wepartition the sources of variation? Write a formula for this. Ifyou want to measure the sources of variation, how can this be doneexperimentally? Write out howyou can do this making specific reference to yourformula.

Heritability can be defined in two ways.What are these definitions and how are they different?

Not all genetic variation is the same. Whatis the difference between additive, dominance, and epistatic formsof genetic variation? Define all three, and update your formula. Inaddition, use a regression plot to schematize additive anddominance variation (ie, box 9.2).

Differential survival and reproduction canbe measured empirically, as can quantitative phenotypes of nearlyany organism. From these we can calculate selection differentialsand selection gradients. What are selection differentials andgradients?

Selection can act on quantitative traits ina variety of ways. Draw a diagram of what directional, stabilizing,and disruptive selection would look like on the distribution of atrait, then describe and explain the differences. Write concisedefinitions next to each type of selection.

If two populations differ in a trait thathas a high heritability, is it valid to conclude that the twopopulations differ genetically with respect to that trait? Useevidence from section 9.7 to explain why or why not.

greenminnow746

BIOL3044 Lecture Notes - Lecture 16: Queen'S Gambit Declined, Point Given, Elytron

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