information – ( Lab4_SexualSelection_2017-18 – NEW PROCEDURE
PART 3.pdf)- link

sexual selection lab report bio 1020 trent university

QUESTION 4

Is there variation in claw size among male crayfish that was
observed in your lab section (see Part 1, Figure 1 – raw data)?Does
this mean that there is or that there is not scope for selection to
operate in the “population” of crayfish? Why is variation in a
trait relevant to whether or not there is scope for selection to
operate?_____________

QUESTION 5

Part 1: Did the ‘population’ of male and female crayfish in your
lab show sexual dimorphism? How can you tell? Be sure to work the
definition of sexual dimorphism into your answer.
________________

QUESTION 6

What is the slope of the line in Figure 4?

_______________

Figure 4: Ventral view of male (A) and female (B) crayfish. Male
crayfish have two leg-like appendages used for insemination; these
appendages are absent/reduced on female crayfish and females have a
round seminal opening that is absent on males. Source: N.A. Nelson;
Crayfish Dissection Guide

QUESTION 7

In Part 2, what does the slope mean? That is, what does the
slope repesent?_____________

QUESTION 10

QUESTION 12

What does Figure 7 tell you about the impact of variance in
mating success on the strength of selection?__________

QUESTION 13

In the code file (“main.R”) change the sex ratio on line 95 from
0.2 to 0.4 (do not change anything else; be sure N_Matings
on line 96 is still 4 and PopulationSize on line 97 is still
50) . This means that the population will now be comprised
of 40% males (as opposed to only 20% males in your initial run).
Change nothing else. Highlight all the code and click ‘Run’. New
figures will be generated. The magnitude of selection in our
simulated population is now_________ and the average selection
gradient across all simulated populations is now
.________________

QUESTION 14

In the code file (“main.R”) change the number of mating events
(N_Matings) on line 96 from 4 to 8 (be sure to set the
SexRatio on line 95 back to 0.2 and that PopulationSize on line 97
is still 50; the idea here is to compare the effect of changing the
sex ratio versus changing the number of mating events on the
magnitude of sexual selection). This means that there will
now be twice as many mating events per female compared to your
initial run. Highlight all the code and click ‘Run’. New figures
will be generated. The magnitude of selection in our simulated
population is now ___________ and the average selection gradient
across all simulated populations is now .____________

In the code file (“main.R”) change the population size
(PopulationSize) on line 97 from 50 to 100 (ensure that the
SexRatioon line 95 is still 0.2 and that N_matings on line 96 is
set back to 4; the idea now is to examine the effects of doubling
the population size and compare it to the effects of doubling the
sex ratio or doubling the number of mating events). This
means that the population size has doubled compared to your initial
run. Highlight all the code and click ‘Run’. New figures will be
generated. The magnitude of selection in our simulated population
is now__________ and the average selection gradient across all
simulated populations is now . ___________