Studied by 8 people
Populations Distribution
individuals can be distributed or dispersed in an area or volume
3 Populations Distribution Patterns:
Clumped, Uniform, Random
Why Clumped?
to hunt easier
for protection from predators
to share the workload
Creatures clump around resources *
easier to find mates
Why uniform?
animals that are territorial
Why random?
Their distribution is random (plants and their seeds)
What is the formula for population growth or decline?
Change = (B+I) - (D+E)
Age Structure Diagram
a visual representation of the number of individuals within specific age groups for a country, typically expressed for males and females; 0-14 pre reproductive, 15-44 reproductive, 45-85+ post reproductive
How do you calculate population density?
Exponential Population Growth
Biotic potential, intrinsic rate of increase, r= the growth rate of the population if it had unlimited resources; reproduce early, short generation times, long reproductive life, lots of offspring, not realistic,, populations can't grow indefinitely
Environmental resistance
all the combined limiting factors that limit the growth of a population
Density Dependent factors
the size of the population will influence an individual's probability of survival; ex: disease, competition, predation
Density Independent factors
the size of the population has no effect on the individual's probability of survival; ex: floods, fire, pollution, habitat
Carrying Capacity
maximum number of a certain species that a certain habitat can sustain indefinitely without degrading it
Carrying capacity equations
Biotic potential + (Environmental Resistance) = Carrying Capacity
Logistic population growth
A model describing population growth that levels off as population size approaches carrying capacity
Abiotic reproduction
Plants, bacteria, and sponges
It's easy to do
Faster than sexual reproduction
Less Genetic Diversity
Sexual Reproduction
Genetic variability, offspring protection
Males don't give birth
Increase genetic errors
Courtship is costly
r-selected species
many small offspring
no parental care
adapt to unstable conditions
generalists
low ability to compete
early successional species
population fluctuates
K-selected species
fewer large offspring
parental care
used to stability
specialist
can compete
late successional species
steady population
Survivorship curve
a graph that represents the distinct patterns of species survival as a function of age; late loss (k), constant loss, early loss (r)
Why did human exponential growth occur?
Human exponential growth happened because more people survived due to modern medicines such as vaccines and antibiotics
Human exponential growth happened because the food supply got better and increased due to advances in agricultural technologies such as GMOs
Human exponential growth occured because we as humans can expand into a vast variety of biomes making it easier for us to spread out into unclaimed territory
Crude Birth Rate
Number of births per 1000 people in a population per year
Crude Death Rate
Number of deaths per 1000 people in a population per year
Crude migration rate
Number of migrants/ 1000
Natural Increase in a population
CBR-CDR = Natural +/-
% change with crude numbers
CBR-CDR/10
Doubling Time (Rule of 70)
Annual growth rate = 70/doubling time
Doubling time = 70/% growth
Population growth with real numbers
New population = (B+I) - (D+E)
New- Old/Old multiplied by 100 = percent change
Fertility
the number of children born to a woman in her entire lifetime
Total Fertility Rate:
the average number of children a typical woman has
Replacement Level Fertility
the number of children a couple must have in order to replace themselves
What affects birth rates and fertility?
Increase:
Children as labor
Culture/Norms
Infant Mortality
Religious Beliefs
Decrease:
Private and Public pension
Culture/Norms
Education and Employment for women
Average age at marriage
Availability to legal abortions
Availability of birth control
Cost of education/raising
Death rates have declined because of...
Increased food supplies, better nutrition.
Advances in medicine.
Improved sanitation and personal hygiene.
Safer water supplies.
Best indicators of overall health?
Life expectancy and infant mortality rate
The Demographic Transition
Phenomenon and theory which refers to the historical shift from high birth and death rates to low birth and death rates as societies attain more technologies, education, and economic developments
Demographic Traps
When countries get stuck in stage 2; death rate goes down, birth rate doesn't; ex. African HIV/AIDS epidemic
Stage 1
Pre-industrial; birth and death rates high; Total Fertility Rate: >2.0
Stage 2
Transitional; death rate drops; cultural lag time occurs; Total Fertility Rate= > 2.0
Stage 3
Industrial; birth rate drops; total fertility rate= > 2.0
Stage 4
post-industrial, Birth rate = death rate, total fertility rate= 2.0
Stage 5
post-industrial, Birth rate is lower than death rate, total fertility rate= < 2.0
Probability
how likely it is that harm will be suffered from a hazard
Risk assessment
the scientific assessment of how much harm a particular hazard can cause to human health or the environment
Risk Management
whether or how to reduce the risk to what level at what cost
Types of Risks
Biological Hazards
Chemical Hazards
Physical Hazards
Cultural Hazards
Biological Hazard
Disease
Non-transmissable diseases
diseases not caused by living organisms cannont spread from one person to another; ex: cardiovascular disorder, asthma, malnutrition
Transmissible/infectious diseases
caused by living organisms such as bacteria and viruses can spread from person to person; top 4 people die from: 1) diarrheal diseases 2) Tuberculosis 3) HIV/AIDS 4) Malaria
Transmissible disease caused by fleas and how to avoid it
Plague, Rat Traps
Transmissible diseases caused by mosquitoes and how to avoid them
Zika, West Nile Virus, Malaria; bug spray, wear long clothes, mosquito net
Transmissible diseases caused by someone coughing on you and how to avoid them
Tuberculosis, Severe Acute Respiratory Syndrome, Middle East Respiratory Syndrome; Wear a mask and wash your hands if exposed
Transmissible diseased caused by infected water and how to avoid them
Cholera and Dysentery; filter/boil your water
Chemical hazards
can harm because they are flammable, explosive, irritate, interfere with oxygen uptake, induce allergic reactions
Mutagens
chemicals or forms of radiation that can mutate DNA (nitrites in hot dogs)
Teratogens
cause harm or birth defects to a fetus or embryo (alcohol, DDT,lead)
Carcinogens
chemicals or radiation that can cause or promote cancer (tumors)
Note 
Flashcard (41)