# DEMOGRAPHY - PowerPoint PPT Presentation

PPT – DEMOGRAPHY PowerPoint presentation | free to download - id: 66fa4d-Y2ExM

The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
Title:

## DEMOGRAPHY

Description:

### Title: PowerPoint Presentation Author: Jennifer Templeton Last modified by: jtemplet Created Date: 11/3/2011 11:46:45 PM Document presentation format – PowerPoint PPT presentation

Number of Views:30
Avg rating:3.0/5.0
Slides: 20
Provided by: JenniferT6
Category:
Transcript and Presenter's Notes

Title: DEMOGRAPHY

1
DEMOGRAPHY
The study of birth and death processes that
determine growth and age structure of a
population.
2
Each age class of a population has an expected
Mortality rate
Fecundity rate
3
Demographic characteristics can be represented in
• Life Tables
• summarize deaths and/or births
• in different age classes of a population
1. Conventional life table

4
Cactus
5
Demographic characteristics can be represented in
• Life Tables
• summarize deaths and/or births
• in different age classes of a population
1. Conventional life table
2. Diagrammatic life table (flow diagram)

6
Diagrammatic Life Table
in each age class
Fecundity
Probability of survival
(Assumes 50-50 sex ratio)
7
2) Survivorship Curves
1,000
I
100
II
Number of survivors (log scale)
10
III
1
0
50
100
Percentage of maximum life span
Fig. 53-6
8
Imagine that a species of fish used to be a
broadcast spawner (producing many eggs that then
get no subsequent parental care) but has evolved
to be a mouth brooder (holding the eggs in the
parents mouth until they hatch and then caring
for the young for a while). We would expect the
survivorship curve of this species to shift
• A) from Type I to Type II or III.
• B) from Type II to Type I.
• C) from Type III to Type I or II.
• D) from Type II to Type III.
• E) The survivorship type would vary unpredictably.

9
POPULATION DENSITY
10
Population Dynamics
11
Population Density (Abundance) of individuals
of the same species that occur in a given area.
Knowing the population density of a particular
species is important for conservation and
management decisions.
12
White Abalone
13
Bald Eagles
14
White-tailed deer
15
Density Estimation (Sampling) Techniques
1. Census (direct counts)
2. Indirect counts
3. Sample plots or transects
4. Mark-recapture

16
• Mark-recapture Technique
• capture and mark several, then release all
• soon after, capture more, SOME of which
• have marks (recaptured)

17
Reasoning Proportion of 2nd capture that
are recaptured individuals represents
the proportion marked in entire population...
R/C M/N
M caught and Marked in first trapping session
C Caught in second trapping session
R marked individuals Recaptured
N estimated Number in entire population
18
R/C M/N
So, N M / (R/C)
N (M x C) / R
19
Assumptions of mark-recapture technique
• closed population (no immigration or emigration)
• no births or deaths (in sampling period)
• marked and unmarked individuals
• equally likely to be caught in second trapping