Deck 9: Life Tables and Demography

Question 1

A cohort is

A) A group of same aged young which grow and survive at different rates
B) A group of different aged young which grow and survive at similar rates
C) A number of individuals alive in different age classes
D) A group of same aged young which grow and survive at similar rates
E) A graphical representation of the numbers of individuals alive at various ages

Answer 1

A group of same aged young which grow and survive at similar rates

Question 2

Survivorship of which of the following organisms is likely to be analyzed with a static life table?

A) Butterfly
B) Annual plant
C) Elephant
D) American robin
E) Barnacle

Answer 2

Elephant

Question 3

In a life table, q_x is

A) The number alive at the start of a time period
B) The number dying during a time period
C) The proportion dying during a time period
D) The proportion surviving during a time period
E) Life expectancy

Answer 3

The proportion dying during a time period

Question 4

In a life table the proportion of individuals surviving in an age class is given by

A) n_x
B) d_x
C) l_x
D) q_x
E) e_x

Question 5

If n₀ = 100 and d₀ = 20, what is q₀?

A) 0.2
B) 0.8
C) 5.0
D) 800
E) 2

Question 6

The following data represent sparrow survival, from age 0-6 on an offshore Canadian island: 115, 25, 19, 12, 2, 1, 0. In which age is the proportion surviving the highest?

A) Year 1
B) Year 2
C) Year 3
D) Year 4
E) Year 5

Question 7

If n₂ = 800 and d₂ = 200, what is n₁?

A) 0.25
B) 4.0
C) 600
D) 1000
E) 160,000

Question 8

In a life table q_x=

A) n_x/n₀
B) n₀/n_x
C) d_x/n_x
D) n_x/d_x
E) n_x +n_x+1/2

Question 9

If n_x = 600 and n_x+1 = 400, what is L_x?

A) 0.67
B) 1.5
C) 200
D) 500
E) 1000

Question 10

The following data give the numbers of gypsy moth life history stages in a forest in Connecticut over a generation: eggs 450, young caterpillars 315, older caterpillars 57, pupae 47, adults 16. In which stage is the mortality rate the highest?

A) eggs
B) young caterpillars.
C) older caterpillars.
D) pupae
E) adults.

Question 11

If n_x = 100, l_x = 0.8, q_x = 0.2, L_x = 50 and T_x = 2000, what is e_x?

A) 0.25
B) 4
C) 20
D) 40
E) 500

Question 12

Given the following data which details numbers of turtles in subsequent years from birth to death, which type of survivorship curve is supported?
Data: 1000, 500, 250, 125, 63, 32, 16, 8, 4, 2, 1, 0.

A) Type I
B) Type II
C) Type III
D) Type IV

Question 13

The number of offspring born to females of a given age is

A) l_x
B) m_x
C) l_x m_x
D) $\Sigma$ l_x m_x
E) $\Sigma$ _xl_x m_x

Question 14

Net reproductive rate, R₀, is given by

A) l_x
B) m_x
C) l_x m_x
D) $\Sigma$ l_x m_x
E) $\Sigma$ _xl_x m_x

Question 15

If N_t = 50 and R₀ =2, N_t+1=

A) 0.04
B) 25
C) 52
D) 100
E) 1000

Question 16

A population increases in size if R₀

A) <1
B) =0
C) =1
D) >1

Question 17

If R₀=1 then we say population size is

A) Decreasing
B) At equilibrium
C) Increasing
D) Declining
E) Going up

Question 18

If?_xl_xm_x for a population rats is 2.0 and the net reproductive rate is 1.6, then what is the average generation time?

A) 0.4
B) 0.8
C) 1.25
D) 2.0
E) 3.6

Question 19

A cohort life table follows a group of individuals from birth to death.

Question 20

A survivorship curve for barnacles in Washington state shows huge mortality in the first years of life.

Question 21

Cohort survivorship curves ignore environmental variation.

Question 22

Larger organisms generally have longer generation times.

Question 23

You need to get the most accurate survivorship curve for a rare parrot. The best method is to construct a cohort life table?

Question 24

Shooting older males of Dall Mountain sheep would increase the q_x of later age groups.