2 - Human population growth Flashcards
(34 cards)
Current world population
8.175 billion
What is a population? When referring to humans?
Individuals of the same species that co-occur in the same space and time
All humans are considered one population because we can travel/disperse so easily
Populations grow or shrink based on… (5)
- current size (at time T0) of the population
- birth rates
- death rates
- immigration and emigration
- carrying capacity (K)
What is carrying capacity
The number of individuals of a particular species the local environment can support
When the size of a population reaches carrying capacity, population growth “will” stop
Why is carrying capacity different for humans than other populations?
- cultural evolution and technological advancements
- we enhanced our ability to exploit natural resources through innovation
- effective carrying capacity of our ecosystems is difficult to calculate
What is population density
The number of individuals per unit area
What is population distribution/dispersion?
The spatial arrangement of individuals within the population
Types of population distribution
- Random (no pattern associated with any factor)
- Regular/even
- Clumped (or clustered; e.g. humans)
What is the age structure of a population?
Percent of that population of different ages
What is age distribution affected by
- periods of successful reproduction
- periods of high and low juvenile and adult survival
- whether the older individuals in a population are being replaced by younger individuals
- whether population is declining
What is age-class structure? X and y axis of the graph?
Number of males and females in a population at different ages (pre-reproductive, reproductive and post-reproductive)
x-axis = number of individuals of each age class (width of bars)
y-axis = age classes
What does an age class diagram look like when the population is expanding? Declining?
Expanding = wider at the bottom (more individuals at pre-reproductive age)
Declining = narrow at bottom (less young individuals)
What is logistic population growth?
A small population will initially growth rapidly, then growth will slow and stop as the population reaches its carrying capacity
Resource use of more-developed vs less-developed countries
More: 17% of the world’s population, use 70% of world’s natural resources
Less: 83% of the world’s population, use about 30% of worlds natural resources
Three scientific principles of sustainability
- Solar energy
- Chemical cycling
- Biodiversity
How do modern people have a better quality of life?
- humans have developed useful materials and products
- life spans increasing
- greatest reduction in poverty in history
- food supply more abundant and safer
- exposure to toxic chemicals more avoidable
What is environmental degradation
Wasting, depleting and degrading the natural capital
How much of earths surface is affects by human activities? For what?
83% of earth’s land surface
Urban development, crop, energy production, mining, timber, etc
What is the Malthusian catastrophe?
Created by Thomas Malthus
If population rates grow geometrically and food abundance increases linearly, then humans will run out of food leading to war, disease, and general chaos
Have we reached the malthusian catastrophe?
Globally, no
Sub-nationally, maybe? e.g. Rwandan genocide (elite began to kill off people bc they did not want to share resources)
What is the Malthusian trap
More resources =
higher standard of living (people do not limit themselves) =
increase in population =
resources are depleted =
standard of living decreases =
more resources…
What is catastrophism?
Malthusianism
Uncontrolled growth of the human population could lead to a population crash due to…
- pandemic
- famine
- decline in carrying capacity
- nuclear holocost
- natural catastrophe
The dark side of Malthusianism (examples)
English implemented Malthus’s ideas: isolated Ireland and let them die of famine, disease
Eugenecists: selectively breed for ‘better’ human population
One child policy in China
What is ecological footprint
A tool used to express the environmental impact of an individual (per capita) or a population or a country
