Answers to Questions:
1. Both graphs 1 and 2 at first glance seem similar. However it is obvious that graph 1 has a much less step slope than graph 2. Graph 1 presents a more a relatively constant slope until old age. It declines at a almost linear rate. Therefore, graph 1 represents a type 2 curve. In graph 2, the humans produced few young but these young had a high probability of living to a reproductive age, therefore representing a type 1 curve.
2. Yes, all the graphs fit the general model of survivorship curve. Although, they are not perfect matches it is obvious that there is a trend between the graphs and the curve types.
3. These graphs illustrate that humans reproduce at around their early 20’s. Humans tend to die of old age. It also shows that humans reproduce low numbers but they survive for a long time.
4. On evolution and human reproductive strategy, the curves show that humans reproduce at a slower rate but live much longer than other creatures. Also, we can assume that humans evolve at much slower rate as a result of a slower reproduction rate. Graph 1 is more like a straight line, signifying that humans have a chance of dying at any age. Graph 2 suggests that humans have a decent chance of dying before age 40, but after 40 the probability of death becomes very likely.
Humans and lobsters live very different lifestyles. While humans tend to reproduce less but surive longer periods of time since they have no real predators, lobsters reproduce a lot more and die much quicker. This is obvious in the very different survivorship curves produced. The survivroship per 1000 for humans shows a gradual decline from 1000 in the 0-9 range to 0 in the 110+ age. On the otherhand, the survivorship per 1000 for lobsters took a sharp decline from 1000 in the 0-9 age range to .119 in the 10-19 range. Afterwards there was very steady survivorship for the lobsters that survived. The human graphs were an arching type 1/2 curve while the lobster graph portrayed the other extreme, a type 3 curve. It makes sense for the lobsters to have a type 3 curve since the young die at an early age and only the fittest survive. So, the lobsters have to produce a large amount of children in order to make sure at least some survive. However, those who survive do usually live for a long time at a constant rate. Humans have no predators so it is easier for them to reproduce less because they are more likely to survive. Survivorship for young humans is high and low for older humans.