HUMAN POPULATION ECOLOGY - -RECAP
Population Ecology deals with populations within an area and how they change over time.
• Ecology: Deals with the interrelationships between organisms and their environment.
The Environment is divided into;
• Biotic = Living parts of the environment
✓ Plants
✓ Fungi
✓ Animals
✓ Bacteria
• Abiotic = Non-living parts of the environment
✓ Light
✓ Water
✓ Temperature
Ecologist = Is a scientist which studies the interactions between conspecifics and member of
other species with their environment.
Ecologists study communities by
• Sampling
• Analyzing the richness and abundance of species grouped by taxonomy or appearance.
The term Ecology was coined in “1866” by German zoologist called ERNST HAECKEL
Kirchner and Schroter divided ecology into two (2) main groups:
➢ Autecology (Species Ecology) – studies interactions between individual organism of a
species with living and non-living factors of their environment.
➢ Synecology – studies communities of organisms and how they relate with their
environment.
1. Organismal Ecology – studies the morphology, physiology and behavior adaptations that can
enable an organism survive in a specific habitat.
2. Population Ecology – studies the number of individuals in a well-defined area and how the
population size changes over time.
3. Community Ecology – studies how organisms interact with each other and their environment.
4. Ecosystem Ecology – studies energy flow and chemical cycling in given area.
Individual – Population – Community – Ecosystem – Biome – Biosphere
,Population Ecology
It is the study of the factors which determine the abundance of species.
It is concerned with the;
• Identification &
• Mode of action of those which cause fluctuations in the population size.
Population Ecology can also be defined as
= Population ecology is a sub-field of ecology that deals with the dynamics of species and how
these populations interact with the environment.
= Population ecology is a branch of biology that deals with the number of individuals of a
particular species that are found and how why those numbers change over time.
= Population ecology is the study of populations in relation to the environment including
environmental influences on population density and distribution, age structure and population
size.
NOTE: Population Ecology is also referred to as DEMECOLOGY
HUMAN POPULATION ECOLOGY
It studies how human population structure and growth change over time.
• It involves the interrelationships among people, other organisms and their
environments.
• It emphasizes on complexity and change.
• It studies the structure, function and processes of human settlements.
POPLUATION AND DEMOGRAPHIC VARIABLES
➢ Population – a group of organisms of the same species separated ore or less clearly in
time or space from other groups of the same species.
➢ Demography – is the study of human population growth and structure. {demography =
from Greek word = “description of people”}
it examines
• The size and composition of populations
• Movement of people from place to place.
Population Growth
The size of a population is influenced by three {3} main factors;
✓ Fertility
✓ Mortality
✓ Migration
Societies grow in populations mainly through internal causes such as;
, ▪ High birth rates
▪ External causes;
❖ Immigration
Population declines through
❖ Deaths
❖ Emigration or
❖ Both
Population = (Births + Immigration) – (Deaths + Emigration)
N/t = B -– D
Where;
N = population size
t = time
B = absolute number of births during the time interval
D = absolute number of deaths during the time interval.
• FERTILITY
It refers to the number of children that an average woman bears during her reproductive years.
✓ It measures the relative frequency with which birth occurs in the total population.
FECUNDITY = refers to the number of children an average woman is capable of bearing during
her reproductive years {15 – 49 years}
➢ Fertility is a function of fecundity.
Fertility Determinants
➢ Biological Determinants
✓ Time lost during pregnancy(ies)
✓ Time lost after delivery or before fecundity resumes
✓ Waiting time on conception
✓ Time lost because of fertility owing to age or a pathological condition
✓ Time lost due to naturally occurring intra-uterine mortality
Menarche = The beginning of a menstrual function.
➢ Behavioral Determinants of Fertility
✓ Extent of exposure to the
✓ Extent of exposure to the possibility of conception (time spent married and/or
having sexual relations)
, ✓ Extent of practice of breastfeeding (prolong postpartum in fecundability)
✓ Use of contraceptives (believed o be the most important determinant)
✓ Induced abortions
Measures of Fertility
• Crude birth rate
• General birth rate
• Age specific fertility rate
• Age specific marital fertility rate
• General marital fertility rate
• Total marital fertility rate
• Total fertility rate
• Gross reproduction rate
• Net reproduction rate
INFERTILITY = refers to the absence of liveborn children or the presence of few children
STERILITY = refers to the possible physiological status underlying childness.
NOTE: In order for a country’s population to be steady, the fertility rate needs to 2.1, which
replaces the parents and accounts for mortality due to unexcepted causes.
MORTALITY
It refers to the number of deaths in a society. It also influences population size.
Cancer and cardiovascular disease are leading causes of death in develop countries.
Mortality Determinants
➢ Income
➢ Nutrition
➢ Public health/environmental issues
Top 10 Causes of Death in Developing Countries
1. Coronary Heart Disease {CHD}
▪ In 2015 = 7.4 million deaths
2. Lower Respiratory Infections
▪ More than 1.5 million deaths annually
3. HIV/AIDS
▪ In 2016 = 1 million deaths {was a leading cause of death in Africa; due to
increased education on prevention treatment, is no longer the case}
Population Ecology deals with populations within an area and how they change over time.
• Ecology: Deals with the interrelationships between organisms and their environment.
The Environment is divided into;
• Biotic = Living parts of the environment
✓ Plants
✓ Fungi
✓ Animals
✓ Bacteria
• Abiotic = Non-living parts of the environment
✓ Light
✓ Water
✓ Temperature
Ecologist = Is a scientist which studies the interactions between conspecifics and member of
other species with their environment.
Ecologists study communities by
• Sampling
• Analyzing the richness and abundance of species grouped by taxonomy or appearance.
The term Ecology was coined in “1866” by German zoologist called ERNST HAECKEL
Kirchner and Schroter divided ecology into two (2) main groups:
➢ Autecology (Species Ecology) – studies interactions between individual organism of a
species with living and non-living factors of their environment.
➢ Synecology – studies communities of organisms and how they relate with their
environment.
1. Organismal Ecology – studies the morphology, physiology and behavior adaptations that can
enable an organism survive in a specific habitat.
2. Population Ecology – studies the number of individuals in a well-defined area and how the
population size changes over time.
3. Community Ecology – studies how organisms interact with each other and their environment.
4. Ecosystem Ecology – studies energy flow and chemical cycling in given area.
Individual – Population – Community – Ecosystem – Biome – Biosphere
,Population Ecology
It is the study of the factors which determine the abundance of species.
It is concerned with the;
• Identification &
• Mode of action of those which cause fluctuations in the population size.
Population Ecology can also be defined as
= Population ecology is a sub-field of ecology that deals with the dynamics of species and how
these populations interact with the environment.
= Population ecology is a branch of biology that deals with the number of individuals of a
particular species that are found and how why those numbers change over time.
= Population ecology is the study of populations in relation to the environment including
environmental influences on population density and distribution, age structure and population
size.
NOTE: Population Ecology is also referred to as DEMECOLOGY
HUMAN POPULATION ECOLOGY
It studies how human population structure and growth change over time.
• It involves the interrelationships among people, other organisms and their
environments.
• It emphasizes on complexity and change.
• It studies the structure, function and processes of human settlements.
POPLUATION AND DEMOGRAPHIC VARIABLES
➢ Population – a group of organisms of the same species separated ore or less clearly in
time or space from other groups of the same species.
➢ Demography – is the study of human population growth and structure. {demography =
from Greek word = “description of people”}
it examines
• The size and composition of populations
• Movement of people from place to place.
Population Growth
The size of a population is influenced by three {3} main factors;
✓ Fertility
✓ Mortality
✓ Migration
Societies grow in populations mainly through internal causes such as;
, ▪ High birth rates
▪ External causes;
❖ Immigration
Population declines through
❖ Deaths
❖ Emigration or
❖ Both
Population = (Births + Immigration) – (Deaths + Emigration)
N/t = B -– D
Where;
N = population size
t = time
B = absolute number of births during the time interval
D = absolute number of deaths during the time interval.
• FERTILITY
It refers to the number of children that an average woman bears during her reproductive years.
✓ It measures the relative frequency with which birth occurs in the total population.
FECUNDITY = refers to the number of children an average woman is capable of bearing during
her reproductive years {15 – 49 years}
➢ Fertility is a function of fecundity.
Fertility Determinants
➢ Biological Determinants
✓ Time lost during pregnancy(ies)
✓ Time lost after delivery or before fecundity resumes
✓ Waiting time on conception
✓ Time lost because of fertility owing to age or a pathological condition
✓ Time lost due to naturally occurring intra-uterine mortality
Menarche = The beginning of a menstrual function.
➢ Behavioral Determinants of Fertility
✓ Extent of exposure to the
✓ Extent of exposure to the possibility of conception (time spent married and/or
having sexual relations)
, ✓ Extent of practice of breastfeeding (prolong postpartum in fecundability)
✓ Use of contraceptives (believed o be the most important determinant)
✓ Induced abortions
Measures of Fertility
• Crude birth rate
• General birth rate
• Age specific fertility rate
• Age specific marital fertility rate
• General marital fertility rate
• Total marital fertility rate
• Total fertility rate
• Gross reproduction rate
• Net reproduction rate
INFERTILITY = refers to the absence of liveborn children or the presence of few children
STERILITY = refers to the possible physiological status underlying childness.
NOTE: In order for a country’s population to be steady, the fertility rate needs to 2.1, which
replaces the parents and accounts for mortality due to unexcepted causes.
MORTALITY
It refers to the number of deaths in a society. It also influences population size.
Cancer and cardiovascular disease are leading causes of death in develop countries.
Mortality Determinants
➢ Income
➢ Nutrition
➢ Public health/environmental issues
Top 10 Causes of Death in Developing Countries
1. Coronary Heart Disease {CHD}
▪ In 2015 = 7.4 million deaths
2. Lower Respiratory Infections
▪ More than 1.5 million deaths annually
3. HIV/AIDS
▪ In 2016 = 1 million deaths {was a leading cause of death in Africa; due to
increased education on prevention treatment, is no longer the case}
