Download Document

Data Management PRACTICE (2)
Full Name: _________________________
Date: ________
Period: ___
1.
Marine iguanas (Amblyrhynchus cristatus) are found on the Galapagos Islands of Genovesa and Santa Fe.
Marine iguanas are unique among lizards in that they feed on algae in the intertidal zone. Between feeding they
lie in the sun to warm themselves. Male iguanas establish territories on the rocks where females lie. Males
provide no parental care of offspring while females guard the nest for a few days. Females mate once and use
up 20% of their body mass in reproduction, while males try to mate more than once and do not use up much of
their body mass.
The graphs below show the lengths of males and females on the two different islands, sample size (N) is
indicated for each graph.
(a)
(i)
State the most frequent range of body sizes of males on Santa Fe and males on Genovesa.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Suggest one reason for the difference in size between male marine iguanas on Santa Fe and
Genovesa.
...........................................................................................................................
...........................................................................................................................
(1)
1
(b)
Compare the body size of males and females.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
Explain, using the theory of natural selection, the significance of size in males and females.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
2
2.) Birds have several different types of feathers. 'Primary' feathers are used in flying. A primary feather is
shaped like an airplane wing. It has two flat surfaces on each feather, called vanes. The vanes are asymmetric
(not equal in shape). The inner vane is called the trailing vane, and the outer vane is called the leading vane.
Vane asymmetry is a measure of the trailing vane width divided by the leading vane width.
Leading vane of a feather
Trailing vane of a feather
1
2
3
4
5
6
7
Primary feathers
8
9
6
10
5
4
3
2
1
The primary feathers on the wings of 71 different bird species that can fly were measured for their asymmetry.
The same measurements were carried out on 18 different species of flightless birds (birds that cannot fly). For
each species, 20 birds’ feathers were measured. The result of this research is shown in the charts below.
15
Modern flying birds
10
5
0
0.20
0.75
1.25
1.75
2.25
2.75
3.25
3.75
4.25
4.75
5.25
5.75
6.25
6.75
7.25
7.75
8.25
8.75
9.25
9.75
10.25
10.75
11.25
11.75
Number
of bird
species
Asymmetry / arbitrary units
6
5
Number
of bird
species
Modern flightless birds
4
3
2
0
0.20
0.75
1.25
1.75
2.25
2.75
3.25
3.75
4.25
4.75
5.25
5.75
6.25
6.75
7.25
7.75
8.25
8.75
9.25
9.75
10.25
10.75
11.25
11.75
1
Asymmetry / arbitrary units
[Source: J. R. Speakman & S. C. Thomson,“Flight capabilities of Archaeopteryx”, Nature (18 August 2004), vol. 370, issue 6490, p. 514, © 2004]
Note: The asymmetry measurements are categories, with the printed number representing the maximum
value; for example, “3.25” indicates 2.76-3.25. However, for the purposes of these questions, you will assume
that each bird species has exactly the asymmetry stated. (All birds in 3.25 have an asymmetry of exactly
3.25)
3
a) What is the minimum asymmetry recorded in modern flying birds?
____________________ (1)
b) How many species of modern flightless birds have an asymmetry of 1.75?
____________________ (1)
c) Calculate the mean (average) asymmetry for the modern flightless birds. (Show your working) (2)
____________________
d) Compare AND contrast the amount of asymmetry between the modern flying birds and the modern
flightless birds.
……………………………………………………………...................................................................................................................................
……………………………………………………………...................................................................................................................................
……………………………………………………………...................................................................................................................................
…………………………………………….…………...................................................................................................................................(2)
e) A t-test using this data gives a p-value of 0.01 for wing asymmetry between modern flying and flightless
birds. Explain the meaning of this result.
……………………………………………………………...................................................................................................................................
…………………………………………….…………...................................................................................................................................(2)
(f) Archaeopteryx is a fossil bird-like creature whose wing feathers have been preserved in the fossil record.
Primary feathers of two fossil Archaeopteryx specimens were measured. The mean (average) asymmetry for
this bird is 1.44.
On the basis of the data given, predict whether Archaeopteryx could fly or not. (1)
Circle one:
Archaeopteryx COULD / COULD NOT fly.
Support you answer with evidence:
……………………………………………………………………..........................................................................................................................
………………………………....................................................................................................................................................................... (1)
Evaluate the strength of the evidence for your prediction. (In other words, how confident should you be that
your answer is correct and WHY?)
…………………………………………………………………….........................................................................................................................
…………………………………………………………………….........................................................................................................................
………………………………………….......................................................................................................................................................(1)
4
Mark Scheme:
1.
(a)
(i)
(ii)
(b)
(c)
Santa Fe 370–380 mm; (units needed)
Genovesa 250–260 mm; (units needed)
Both needed for [1]
(1)
food availability / predation / competition /
territory size / different selection pressures
Any other valid suggestions.
(1)
males are generally bigger than females on both islands /
females tend to be smaller;
maximum size of males is greater than females
on each island;
range of male sizes greater than range of female
sizes on each island;
range of males and females sizes overlap;
males have to defend territory for mates;
bigger males more successful mating;
bigger males pass on their genes / size trait;
longer length in females seems advantageous;
max
Other valid explanations.
(2)
(2)
2.
(a) 2.25
(1)
(b) 4
(1)
(c) one point for showing calculations; one point for correct answer
(2)
(3 x 0.75) + (5 x 1.25) + (4 x 1.75) + (2 x 2.25) + (2 x 2.75) + (1 x 3.25) + (1 x 3.75) / 18
allow 1 mark if students forget to multiply by the number of species.
Allow between
1.80 - 1.81
(d) Any TWO of:
Shared range is 2.25 to 3.75; flightless has a smaller range;
flightless has a lower mean / median /mode;
max is 3.75 in flightless v. 11.75 or min is 0.75 flightless v. 2.25;
all species has some asymmetric / at least 0.75;
other reasonable answer.
(2)
(e) The difference (of asymmetry) is significant;
Because the p-value is below the 0.05 cutoff of statistical significance.
(2)
(f) COULD NOT fly.
(1)
Support you answer with evidence:
1.44 is lower than the lowest recorded flying asymmetry;
1.44 is in the range of flightless birds but not flying birds;
(1)
Evaluate the strength of the evidence for your prediction.
For this points students MUST do more than restate the evidence above.
They MUST discuss the reliability of the data.
Not very confident because …
only two Archaeopteryx specimens were measured;
Archaeopteryx may have had other adaptations allowing flight different from modern birds;
Although there are examples of flying species below 2.25 that does not mean it is the absolute
lower limit for flight;
Other reasonable answer
(1)
5