19.1 Understanding Populations

19.1UNDERSTANDING POPULATIONS

1. POPULATION PROPERTIESSize (often hard to measure)

1. POPULATION PROPERTIESSize (often hard to measure)Density– amount of population per unit of area (population crowding)

# of individuals = population density area (units2)

1. POPULATION PROPERTIESSize (often hard to measure)Density– amount of population per unit of area (population crowding)

# of individuals = population density area (units2)

Dispersion – spatial organization of the population

1. POPULATION PROPERTIESDispersion – spatial organization of the population

1. POPULATION PROPERTIESDispersion – spatial organization of the population

•Clumped – population is clustered together, usually around resources or from social behavior

ex/ school of fish

clumped

1. POPULATION PROPERTIESDispersion – spatial organization of the population

•Uniform – the population is evenly dispersed from each other usually from social interactions

ex/ bird nesting sites or solitary predators

uniform

1. POPULATION PROPERTIESDispersion – spatial organization of the population

•Random – the population is randomly scattered throughout the area

ex/ trees in a forest with seeds dispersed by wind or animals

random

2. POPULATION DYNAMICSAge Structure

i. the number of individuals of different ages within the population

2. POPULATION DYNAMICSAge Structure

i. the number of individuals of different ages within the population

ii. different age groups may have different abilities such as birth/death rates

2. POPULATION DYNAMICSSurvivorship Curve

• probability of individuals surviving to a certain age

2. POPULATION DYNAMICSSurvivorship Curve

• probability of individuals surviving to a certain age

I – Low birth rate, low infant mortality, survives to old age (Humans & large mammals)

2. POPULATION DYNAMICSSurvivorship Curve

• probability of individuals surviving to a certain age

I – Low birth rate, low infant mortality, survives to old age (Humans & large mammals)

2. POPULATION DYNAMICS

II – Survivorship rate equal at all ages

(Birds & reptiles)

2. POPULATION DYNAMICS

II – Survivorship rate equal at all ages

(Birds & reptiles)

2. POPULATION DYNAMICS

III – High birth rate, high infant mortality rate (Fish, Insects, Plants)

2. POPULATION DYNAMICS

III – High birth rate, high infant mortality rate (Fish, Insects, Plants)