Life tables in population ecology

  • Thread starter atomant
  • Start date
  • #1
27
1

Homework Statement


http://imgur.com/OInF6O2

The blue table shows the mortality and offspring production rates per year per age class by individuals of an unnamed species. The orange tables shows the starting population at time t, I have to find the number of individuals at T+1 (next year)


Homework Equations



Not sure if relavent but an equation is given: r = ln (NT+1)/NT)/T

The Attempt at a Solution


http://imgur.com/pilNkOP

Would love if someone could check the workings though or see if this makes sense
 

Answers and Replies

  • #2
34,474
10,597
How did you get the first value?
I agree with the others.
 
  • #3
27
1
How did you get the first value?
I agree with the others.
Well the basic idea was to calculate the Mx values for the age groups that had an initial population at times t, which means age groups 2 and 3 which has Mx values of 3 and 2 respectively. Therefore the number of 0 age offspring should be 5 (I think)..don't really know how I got 7. Is this correct?
 
  • #4
34,474
10,597
Those mx values are "offspring per individual and year". It mean a single individual at age 1 will (on average) get 2 children.

How many do 10 at age 2 get then? And the other groups?
 
  • Like
Likes 1 person
  • #5
27
1
Those mx values are "offspring per individual and year". It mean a single individual at age 1 will (on average) get 2 children.

How many do 10 at age 2 get then? And the other groups?
Ah, I see - so the 10 at age 2 will on average have 30 offspring at t+1 (10 individuals and mx of 3).

The question now then is do I assume that all 10 individuals are alive at t+1 to reproduce? i.e- at age 2 the have a mortality rate of 10%, which means 9 individuals will survive at t+1 to become 3yr olds so do I assume that reproduction occurs after the death based on mortality rate happens or do I assume that these 2yr olds will reproduce before dying? Depending on these assumptions the offspring will either be 30 or 27. The question doesn't specify so I am unsure which is the most logical assumption to take.
 
  • #6
34,474
10,597
I would read the table in a way that mortality does not have to be taken into account - in other words, they get children before they can die.
 
  • #7
27
1
Thank you so much for your help, you have been amazing!
 
  • Like
Likes 1 person

Related Threads on Life tables in population ecology

  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
2
Views
6K
Replies
1
Views
750
Replies
1
Views
3K
  • Last Post
Replies
2
Views
8K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
7K
Replies
1
Views
4K
Top