exam 3 Flashcards
Pre-agricultural
Takes 10’s of 1,000s of yrs for population to double in size
Agricultural
Improvements in food supply and nutrition. Takes <10K yrs for pop to double.
Industrial
Life expectancy increases due to advancements that increase food supply and medicine. Doubling time is now decades, not millennia
why is human population growth not always desirable
Growth that outpaces the food supply will lead to famine, disease and war -malthus
Consumption overpopulation
Each individual in a population consumes too large a share of the resources. Highly developed nations
Ecological footprint
The average amount of land, water and ocean required to (sustainably) provide a person with all the resources they consume
Developing Nations
Use fewer resources per person than developed nations. Higher population growth
Developed Nations
Use more resources per person. Lower pop. growth
- Pre-industrial Stage
Birth and death rates high, modest population growth
- Transitional Stage (industrializing)
Death rate declines, rapid population growth rate
- Industrial Stage (mature industrial)
Birth rate declines, population growth slows, esp. near end of stage
- Postindustrial Stage
Low birth and death rates, population growth very slow or in decline
Age Structure
The distribution of a population’s males
and females by age class
Population Growth Momentum
the potential for future increase or decrease in a population based on the present age structure
Total Fertility Rate
the average # of children born to each woman in a population
Replacement level fertility
The total fertility rate necessary to replace those dying in a population
Reasons for High TFRs
Tradition, Infant/child mortality, Child labor for family livelihood, Religious beliefs, Gender inequality
Single most important factor affecting high TFR
Gender Inequality
When gender inequality is high, for
women, marriage can offer
improved social status, Economic security
how does age upon marriage affect TFR
the younger you get married, the more kids you have
Family Planning Services
offer information to both men and women on sexuality, contraception, STDs, and parenting
china vs mexico population reduction policies
china: one child policy, doesn’t have enough young people now, skewed gender ratio
mexico: education reform, FPSs, better health care; TFR dropped
Effects of negative population growth momentum or a high percentage of elderly
reduces productive workforce, Increases tax burden, Strains social systems like healthcare, pensions, social security
government policies to reduce TFR
Increasing age of retirement
* Decreasing benefits for elderly
* Balancing age structure by:
– Encouraging immigration
– Offering incentives for having children
Developing countries TFR
Increase $$ allotted to pubic health & FPSs
* Increase average level of education
* Increase gender equality through education
Developed countries TFR
Provide financial support to developing nations
* Support R&D for contraceptives and disease
prevention
* Address our own over population problem: overconsumption
species diversity
variety of species taking into account species richness and evenness
genetic diversity
variety of genes within a population
ecosystem diversity
variety of ecosystems in an area
species richness
total number of species in an area
species evenness
the relative abundance of each individual species in an area
are simple or complex ecosystems more affected by a loss. what does genetic diversity help withstand
simple because genetic diversity helps withstand adversity
why is biodiversity important to humans
food, shelter, clothes, medicine, pollination, biological processes
Genetic Engineering
incorporation of genes from one organism into a different species genes
Ecosystem services
important environmental benefits that ecosystems provide to all life, including people
Natural Selection
the tendency of organisms with traits that are favorable to their environment to survive and pass those traits on to the next generation
Darwin’s theory of natural selection is based on what four observations
heritable variation, overproduction, struggle for existence, Differential Success & Reproduction
Jean Baptiste de Lamarck: Heritability of Acquired Characteristics
Proposed that organisms pass traits acquired during their lifetime to offspring
Overproduction of species
Each species has the capacity to produce more offspring than will survive to maturity
Struggle for Existence
organisms compete for resources which limits population growth
Differential Success and Reproduction
offspring with more favorable traits are more likely to survive and reproduce
Darwin’s Hypothesis
in the struggle for existence, variations that are favorable to survival are preserved and passed on, while unfavorable variations decline or are eliminated. The end result is adaptation
background extinction
Continuous low-level extinction of spp.
mass extinction
elevated level of extinction over a short period of time
Endangered
species at immediate risk of extinction
Threatened
species who is at risk of endangerment
Extinction Vulnerability factors
small range, range too large, island habitat, low reproductive rates, specialized breeding or feeding areas
Where is Declining Biodiversity the Greatest Problem
US: Hawaii
Globally: tropical rainforests
species endangering activities HIPPO
Habitat loss*
Invasive species
People overpopulation
Pollution
Overexploitation
most endangering activity
habitat loss
Habitat Fragmentation
Break up of large continuous areas of habitat into small isolated areas. creates edge effects and depletes core habitats threatening core species.
Invasive species
spp. introduced into an ecosystem in which they did not evolve and threatens the ecosystem
brown tree snake invasion
killed all the birds in guam which rapidly increased the spider population
Indicator species
species that provide an early warning of environmental problems. frogs and lichen
Overhunting
Unregulated hunting
Poaching
Illegal hunting of protected animals
Commercial Harvest
the collection & sale of live organisms from nature
An example of an invasive species that has wreaked havoc within the United States is the
Hemlock woolly adelgid
Conservation Biology
Scientific study of how humans impact organisms, protect biodiversity, focus on endangered species
what do conservation biologists do
protecting habitats, restoring habitats, captive breeding and species storage (seed banks)
Biodiversity Hotspots
Relatively small areas of land that contain an exceptional # of endemic spp.
single species approach
Focused on specific threats to one individual sp, caused endangered species act, used by early conservation programs
Species Survival Plans
use breeding programs (artificial insemination, embryo transfer) to maximize genetic diversity, reintroduce organisms back to their natural habitat
ecosystem approach
modern approach, protects entire habitats, nature preserves, increases biodiversity overall
single species approach problem
only protects charismatic (cute species) like pandas
metrics to assess ecosystem quality
species richness and evenness, water quality, soil health, non native species abundance
Habitat Corridors
strips of habitat that connect isolated habitat fragments, allow animals to move between habitat fragments, must be wide
Restoration ecology
returning a human-damaged ecosystem to its former state, expensive
Wildlife Management
Management of wild species and their habitats, primarily focus on common species instead of endangered
example of a species that became extinct due to overexploitation
carolina parakeet
Deforestation of tropical rainforests is primarily due to
agriculture
Which of the following is an example of a species that was threatened historically due to overexploitation?
bison
Grain Stock
grains stored from previous harvests to be used during poor harvests and rising prices
what leads to a decline in grain stock
climate change, more grain being used for livestock and ethanol
problem with livestock
nutritious but energy inefficient
Food insecurity
state of fear of not being able to acquire sufficient food
Malnutrition
The impairment of health due to eating too much or too little food
Malnutrition:Undernourishment
lack of nutrients or calories that leaves the body weak and susceptible to disease
Malnourishment:Overnutrition
Malnutrition caused by an overconsumption of calories that leaves the body susceptible to disease
Industrialized Agriculture
- Large mechanized farms
- Large amts of pesticides,
fertilizers, water, & fossil fuel - Most common in industrialized
nations - 25% of worldwide cropland use
Industrialized Agriculture pros
Produces the most food & capital
Industrialized Agriculture cons
- Uses the most E
- Most environmentally damaging
Subsistence Agriculture
- produce enough
food for the family & some to sell - Most common in developing
nations - Manual labor & traditional methods: shifting cultivation, slash & burn, and nomadic herding
Subsistence Agriculture cons
Produces less yield & less capital
Uses more labor and land
Sustainable Agriculture
maintain soil productivity and ecological balance
Moderate to high yield, low impact
use crops adapted for their region
Monoculture
standard in industrialized agriculture
cultivation of only 1 type of plant over a
large area
Polyculture
common in Subsistence Agriculture
cultivation of several types of plants over the same area
dealing with pesticide resistance in bugs
Delay resistance by sacrificing some plants
Introduce & support natural predator populations
what happens with Increased pesticide use
pesticide treadmill
problems with agriculture
pesticide resistance, loss of genetic diversity, Hormones & Antibiotics, GMOs, declines in soil quality and quantity
Germplasm
Any plant or animal material that could be used in breeding
Livestock Factories
large buildings with dense animal populations, lots get sick
gmo benefits
resistant to herbicides, pests, and droughts
more nutritious
opposition to gmos
fear, effects on pollinators, interbreeding with wild species, genetic resistance in pests, ownership issues
The greatest use for cereal grains in the highly developed countries is to
feed livestock
Modern cultivation methods combined with high-yielding varieties of certain popular crops to increase the amount of food produced per designated area characterizes:
green revolution
We are preserving older varieties of germplasm in storage vaults because:
Older plant and animal varieties may have adaptations that have been lost in more modern varieties.
The two areas of the world with the greatest food insecurity are:
South Asia and sub-Saharan Africa.
shifting cultivation
A type of subsistence agriculture which requires large tracts of land and consists of short periods of cultivation followed by lengthened fallow periods
what percent of people suffer from food insecurity
25%
Distribution of Water
Oceans (97.5%), Freshwater (2.5%) mostly ice
Surface water
water that remains on Earth’s surface and does not seep down through the soil
Watershed (drainage basin)
a land area that drains water to a specific body of water, such as a lake, river, or bay
Groundwater
freshwater that’s accumulated underground above an impermeable layer of rock or clay
Aquifer
a water-saturated underground reservoir where groundwater is stored
Water table
upper limit of an aquifer, below which the ground is saturated
Global Water Usage
Agriculture ~ 70%
Industry ~ 20%
Domestic ~ 10%
Human-induced flood problems
- Removing plant cover from soil for agriculture & development
- Draining wetlands
- Building in floodplains
- River channelization
River channelization
straight channels flow much faster, can cause flooding
Human induced water shortage problems
- Drought
- Irrigation depletes surface water & ground water
- Aquifer depletion
what does aquifer depletion lead to
subsidence (sinkholes) and saltwater intrusion
groundwater vs aquifer
Groundwater is water that fills the spaces in underground rock and sediment, while an aquifer is a body of rock or sediment that stores groundwater
what percent of freshwater is usable
.5%
Water shortages in West & Southwest
Decreased snowfall is contributing to shortage
Water is diverted & transported via aqueducts
Mono Lake (Eastern CA)
rivers feeding the lake are diverted to CA
Decreasing in size & Becoming highly saline
Court ordered water diversion reduction
Colorado River
important source of water and hydropower
no longer reaches gulf of CA
Lake Mead
dropped 130 ft
Ogallala Aquifer
largest aquifer in the world
Water withdrawn for agriculture faster than it can be replenished
what global water problems are caused by climate change
Increased rainfall in some areas, less rainfall in others
Sea level rise: Ocean thermal expansion, ice melt
Reduced snowfall
how does pop growth affect water supply
depletes water supply leaving less drinking water
how much human illness is caused by water issues
80%
how do dams increase water supply
Ensure year-round supply of water with regulated flow
how can diverting water increase water supply
by diverting it to areas that are water deficient
how does desalination increase water supply
through distillation and reverse osmosis
Distillation
salt water is evaporated, and water
vapor is condensed into freshwater; salt remains behind and can be toxic
Reverse Osmosis
salt water is forced through a membrane that’s permeable to water, but not to salt
Toilet to Tap
recycling toilet water into usable water
recycling gray water
water that has already been used once, but can be reused, not from toilet
how does water conservation increase water suppy
reducing agricultural waste, reducing industrial water waste, conserving water at home
One way to make agricultural water use more sustainable is through:
microirrigation
Orange County, CA is dealing with its water shortage problem by
toilet to tap
