Chapter 12 Lecture 1 Flashcards Preview

General Ecology > Chapter 12 Lecture 1 > Flashcards

Flashcards in Chapter 12 Lecture 1 Deck (67)
Loading flashcards...
1

under ideal conditions...

populations can grow rapidly

2

demography

the study of populations

3

growth rate

in a population, the number of new individuals that are produced per unit of time minus the number of individuals that die

4

Intrinsic growth rate (r)

the highest possible per capita growth rate for a population.

5

what do individuals experience under ideal conditions

maximum r (i.e., maximum reproductive rates and minimum death rates

6

what does the strength of a reproductive population depend on

1. the number of individuals of reproductive age
2. the availability of resources such as food and mates
3. the presence or absence of predators, disease, etc.

7

how may individuals be added to populations

1. continuous reproduction
2. discrete reproductive periods

8

what does the periodicity with which offspring are produced result in

important differences in the way in which population growth is conceptualized mathematically

9

in many species, young are added only during certain times of the year during...

discrete reproductive periods - such populations undergo geometric growth

10

in geometric growth

the rate of increase is proportional to the number of individuals present in the population at the beginning of the discrete reproductive period

11

what is the typical form of population growth in the wild

geometric growth

12

species that reproduce continually

they can add young at any time of the year

13

what do populations with continual reproduction undergo

exponential growth

14

exponential growth model

a model of population growth in which the population increases continuously at an exponential rate

15

what equation describes the exponential growth model

Nt+ N0e^rt

16

Nt

future population size

17

N0

current population size

18

r

intrinsic growth rate

19

t

time over which a population grows

20

e

2.7183

21

J-shaped curve

the shape of the exponential growth when graphed

22

the rate of a population's growth at any point in time is the derivative of this equation

dN/dt = rN

23

e^r

the factor by which the population increases during each unit of time, and is sometimes symbolized with a lambda

24

exponential growth

results in a continuous curve of increase (or decrease, when the rt term is negative) whose slope varies in direct relation to the size of the population

25

the rate of increase of a population undergoing exponential growth at a particular instant in time, the instantaneous rate of increase =

dN/dt = rN

26

dN/dt = rN
this equation encompasses two principles (A)

1. the exponential growth rate (r) expresses the population increase (or decrease) on a per individual basis

27

dN/dt = rN
this equation encompasses two principles (B)

2. the rate of increase (dN/dt) varies in direct proportion to the size of the population (N)

28

the rate of the change in population size equals

the contribution of each individual to population growth times the number of individuals in the population

29

the individual contribution (per capita) to population growth is the difference between

the birth rate (b) and the death rate (d) calculated on a per capita basis

30

dN/dt = bN - dN or

dN/dt = (b-d)N