Mammals Project
By: Charlie Carrick 9C
Task 1:
Species
Body Weight (g)
Brain Weight (kg)
Goat
Baboon
Giant armadillo
Gray wolf
Giraffe
Gorilla
Jaguar
Kangaroo
Roe deer
Pig
Horse
Sheep
Donkey
Gray seal
Tiger
28
11
60
36
529
207
100
35
15
192
521
56
187
85
200
115
180
81
120
680
406
157
56
98
180
655
175
419
325
B ody Weight vs B rain Weight
800
Brain Weight (g)
700
600
500
400
300
200
100
0
0
100
200
300
400
500
600
Body Weight (kg)
a) The correlation between the body weight and the brain weights are
positive and continuous. I used the graph to show the correlation
more clearly. As you can see, the data is all clustered around the line
of best fit. This is a very good sign, but the line of best fit does not
start at 0, so there is an imperfection in the data collected. For some
animals, however, like the gray seal, gorilla, and the pig, the
correlation is weak. One very strong correlation is the one of the
giraffe. The brain weight is 680 and the body weight is 529. The range
is 151. Some other animals that have strong correlations are the roe
deer, gray wolf, and the goat. Using a scatter graph as a method is
good because using the line of best fit, you can see what kind of
correlation there is and it is easier to read. A disadvantage of using
this method is that it doesn’t tell you why not all of the animals are
near to the line.
b)
B ody Weight vs B rain Weight
800
Brain Weight (g)
700
600
500
400
300
200
100
0
0
100
200
300
400
500
600
Body Weight (kg)
To find an estimate of the brain weight of a Bengal tiger, I find 200 kg’s on
the x axis and draw a line up to the line of best fit. I then draw another line
going across to the y axis and see what number the line ends at. This would
give me an estimate of around 320 g. This is a good estimate, but a
disadvantage is that a tiger could have a different brain weight to body
weight ratio and then the graph would be showing us the wrong answer.
c)
B ody Weight vs B rain Weight
1400
Brain Weight (g)
1200
1000
800
S e rie s 1
600
L in e a r (S e rie s 1 )
400
200
0
0
100
200
300
400
Body Weight (kg)
500
600
Compared to the previous results I collected, the ratio of brain weight to
body weight is way off for a human. A human has the heaviest brain and it is
way off the line of best fit. I would have expected it to be up where the
giraffe was, having a heavier brain than the other animals. I think this tells us
why we have advanced so much more than the other animals; we have a lot
heavier brains.
d)
B ody Weight vs B rain Weight
800
Brain Weight (g)
700
600
500
400
300
200
100
0
0
100
200
300
400
500
600
Body Weight (kg)
I am estimating the cow brain weight the same way I did for the tiger, by
drawing a line up to the line of best fit and across to the y axis, recording the
number I land on. The estimate for a cow’s brain weight is around 600 g.
e)
To find the brain weight of an elephant, I am going to find a connection
between the body and brain weight of a cow. The ratio for a cow is 600g:
465kg. This doesn’t work when the numbers are like this because grams and
kilograms are two different measurements, so I am going to make them
both kilograms. There are 1000 grams in a kilogram, so 600 g in kilograms
is 0.6kg, making my ratio 465kg: 0.6kg. 465 divided by 0.6 is 775. The body
weight of an elephant is 6650kg. 6650 divided by 775 is 8.6 kg. That is 8600
grams.
f) The real brain weight of a cow is 423g and the brain weight of an elephant
is 5712 g. Both of my answers are way too high, telling me that my method
didn’t work very well. Maybe the ratios are too heavy on either the brain or
body weight for the graph, like the animals that are not near the line. This
shows that my method has limitations and is not as accurate and reliable as I
was led to believe before. Also maybe the way I worked it out for the
elephant was wrong, because all I did was times it by 775. This could only
apply to cows, so this could be wrong too.
Task 2:
a)
Gestation Time (days)
L ifes pan vs Ges tation Time
450
400
350
300
250
200
150
100
50
0
0
5
10
15
20
25
30
35
40
45
50
Max. L ifespan (years)
There is an obvious correlation between the lifespan and gestation time and
it is a strong, positive correlation. I have used a scatter graph with a line of
best fit. This is easy to see the correlation and there is only one animal that
is way off the line; the giraffe. Using a scatter graph is very useful because it
shows which animals are different from the others very easily and the line of
best fit shows you very well the patterns in the data. This graph does not
begin at 0, so something must have gone wrong when the data was
collected. The accuracy of the results are very good and you do not need to
explain very much, it is clearly shown, but maybe you would need to talk
about the giraffe and why it is not near the line like all of the other animals.
b)
Gestation Time (days)
L ifes pan vs Ges tation Time
450
400
350
300
250
200
150
100
50
0
0
5
10
15
20
25
30
Max. L ifespan (years)
35
40
45
50
To find the gestation time of an armadillo, I will need to find the maximum
lifespan of a giant armadillo, which is 7. From this, I will find 7 on the x axis,
draw a line up to the line of best fit and across to the y axis. When I follow
these steps, the line I drew lands on around about 10 days. This is not very
accurate because it is hard to see where exactly it lands on the line, having
the first value as 50. Also, none of the other animals fall exactly on the line,
so the armadillo may be the same and is either above or below the line, it is
hard to tell.
b) The human gestation time, compared to our maximum lifespan is very
short. We have the second smallest gestation time, but we have 60 years
longer to live than the animal with the highest lifespan! A kangaroo has the
smallest gestation time and the second smallest lifespan. I think this is
because possibly the kangaroos breed frequently, so the have the fetus for a
short span of time and then they do not live for as long because there are a
lot of them being born.
Task 3:
I am going to compare hour of sleep per day and predation index because
how often you are hunted can depend on how much you sleep each day.
I will use a scatter graph again and put in a line of best fit to see the
outcomes.
Hours of S leep Per Day vs Predation Index
5
Predation Index
4
3
2
1
0
-1
0
2
4
6
8
10
12
14
16
18
20
Hours of S leep Per Day
This graph tells me that the more hours of sleep the animals get, the lower
they re on the predation index. The animals with 5 on the predation index
are the ones most likely to be preyed upon and the animals with 1 on the
predation index are the ones least likely to be preyed upon. On this graph,
the animals with the least amount of sleep each day are high up on the
predation index, so that must mean they get as little sleep as possible
because it is easy to be preyed upon in your sleep. The animals that get a lot
of sleep have less to worry about, so they can get their sleep.
Task 4:
Tiger Population in 1998
Tiger Population in 1998
4000
3500
3000
2500
2000
1500
1000
500
0
B a n g la d e s h
B h u ta n
C h in a
In d ia
M y anpur
N epal
Countries
I have chosen a bar graph to present the tiger population in 1998 because it
shows clearly the distribution and which countries had more tigers than
others. I think a bar graph is a good idea because it shows each country
individually alongside others. A disadvantage is that it doesn’t show the
percentage of the distribution. A different graph could be a pie graph
because it would show the tiger population in percentages in relation to
each other. A disadvantage of this would be that it would not show the tiger
population and how many there are because you wouldn’t know where the
percentages came from and whether it came was 10% of 1,000 tigers or
360,000 tigers.
Task 5:
Number of Tigers
Tiger Population in India
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
1970
1975
1980
1985
1990
Year
1995
2000
2005
As you can see by looking at the graph, my line is actually curving and
going through each of the points in a curve. This is a better method for
showing trends. It shows there was a huge rise in numbers at the beginning
and now it has declined again a little, but it has stabilized. This method is
good for it is very reliable when you want to see progress over a period of
time and see the changes that have occurred. An alternative method for
showing this data would be to show it as a bar graph. This would show the
data compared to each other, but it wouldn’t show the trend over time. I
think the government has been very effective and they obviously worked
really hard at the beginning when it had their full attention, but they slipped
a bit recently and now it looks stabilized and the overall tiger population has
increased.
Task 6:
My first decision for an extra graph is to make one on the body weight and
the maximum lifespan of the languages. Maybe the heavier ones don’t live
as long as the light and nimble ones.
Maximum L ifespan (years)
B ody Weight vs Maximum L ifes pan
50
45
40
35
30
25
20
15
10
5
0
0
100
200
300
400
500
600
Body Weight (kg)
The correlation isn’t very strong, but it is positive. It seems that the heavier
the animal, the longer they live. I made the opposite guess to the graph,
because the animal with the longest life span was very heavy. I chose this
graph because I wondered if the weight of the animals made them die earlier
either by being preyed upon, or because their weight makes them slow, but I
was wrong. Heavy animals like the horse and the giraffe live for a long time,
but they are each over 500kg’s.
My second decision for task 6 is to look at four different kinds of
chimpanzees and compare their different populations.
Population of chimpanzees in 2003 in Africa
P
o
120000
p
100000
u80000
l60000
a
40000
t
20000
i
o 0
n
Eastern chimpanzee Western chimpanzee Central chimpanzee Nigeria chimpanzee
Type of chimpanzee
The blue bars are the minimum population and the purple ones are the
maximum population. I used this method because I was given two sets of
data for each species, so I put the smallest in one bar and the biggest in a
different colour bar right next to it. This chart tells us very well that the
eastern chimpanzee has the highest population followed by the central
chimpanzee. The western chimpanzee has half of that, but the Nigeria
chimpanzee’s numbers seem to be bordering on extinction. This tells me
that in certain parts of Africa, either habitats are being destroyed or there are
poachers killing them.
By: Charlie Carrick 9C