Question

Question 2 1.5 pts Use the cohort life table to answer the question. Age Class Survivorship Mortality Fecundity 0-1 0.50 1-2 0.4 2-3 0.33 3-4 0.5 4.2 4-5 5-6 0.0 Assume the initial population was 1000 individuals and the ratio between males and females was 50/50. Which of the following is TRUE? SELECT ALL THAT APPLY. The age class 4-5 produced 150 offspring. Individuals in age class 2-3 were more likely to die than individuals in age class 3-4. Individuals in age class 1-2 did not reproduce. Only 100 individuals survive to age class 3-4. None of the above are true.

Answer 1

Ans-2 In cohort life table we study about the fate of a group of individuals born at the same time from birth to the death of last individual.

survivorship is the survival of new born individuals to age x, calculated as

survivorship = number of individuals at age x (nx) divided by number of individuals at age 0 or at starting

lx = nx/n0

if the survivorship and number of individuals at age 0 is given then we can calculate number of individuals at specific age

nx = lx X n0

fecundity is the average number of female offspring produced per female in the population over some period of time or a age group. So if the fecundity and number of individulas at an age group is given then we can caculate the number of offsprings prouced during that age group

Now we will calculate number of individuals at all age groups and number of offsprings produced.

age class	number of individuals = lx X n0	survivorship= nx/n0	mortality	fecundity	number of offsprings produced = nx X fecundity
0-1	1000	1.0	0.5	0	1000 X 0= 0
1-2	1000X 0.5 = 500	0.5	0.4	0	500 X 0 = 0
2-3	1000X 0.3 = 300	0.3	0.33	5	300 X 5 = 1500
3-4	1000 X 0.2 = 200	0.2	0.5	4.2	200 X 4.2 =840
4-5	1000 X 0.1 =100	0.1	1.0	3.0	100 X 3 = 300
5-6	1000 X0 =0	0	0	0	0

Now we will see the options

1st option is age class 4-5 produces 150 offsprings is wrong because number of offsprings produced is 300

2nd option individuals in age class 2-3 are more likely to die than individuals of age class 3-4 is wrong because mortality of age class 2-3 is less than mortality of age class 3-4

3rd option individual in age class 1-2 did not reproduce is correct because fecundity of age class 1-2 is 0.

4th option only 100 individuals survive to age class 3-4 is wrong because 200 individuals survive to the age class3-4

5th option none of the above is also wrong because option 3rd is correct.

Ans-5 Population density is calculated as number of individuals divided by land area or

population density = number of individuals / land area

total land area given is 5 square mile divided into 100 equal sized section, average number of deer per section is 5

then total number of deer in 100 section = 100 X 5 = 500

then population density = 500 deer / 5 square mile = 100 deer per square mile

option 4 is correct.

Ans-6 by graph we can see the age of all the species i.e. night lizard 9 years, five lined skink 8 years and texas spiny lizard is texas spiny lizard.

hence option 3 texas spiny lizard is correct