Things to know for test Flashcards
How long ago did humans migrate out of Africa?
100,00 years ago
How long ago did the transition from hunting & gathering to agriculture occur?
10,000 years ago
True/False: The human population is more than 7 billion people
True
Crude Birth Rate
The annual number of births per 1,000 persons
Crude Death Rate
The annual number of deaths per 1,000 persons
Why has the total fertility rate been decreasing?
Because people have been living longer
Demographic Transition
Reduction in death rates and birth rates, usually due to economic development (LDC’s —> MDC’s)
The J-shaped growth curve is associated with what two factors?
Human growth population & the industrial revolution
Demography
The study of population characteristics
What is the percentage of world land usage as far as cropland goes?
11%
What is the percentage of world land usage as far as rangeland goes?
27%
What is the percentage of world land usage as far as forest goes?
29%
What is the percentage of world land usage for others?
33%
Famines
Acute food shortage; drought, pests, politics
Undernutrition
Chronic food shortage
Malnutrition
Chronic food shortage; nutritional imbalance or deficiency
Soil texture
The size of mineral particles
Soil structure
The clumpyness of soil
Adhesion
Water molecules that are attracted to different molecules (such as dirt)
Cohesion
Water molecules attracted to other water molecules
Infiltration Rate
Rate at which water enters a soil
Percolation Rate/Permeability
Rate at which water moves through soil
Runoff = ?
Erosion
What is the first soil layer?
O horizon - surface litter
What is the second soil layer?
A horizon - top soil (TRUE SOIL)
What is the third soil layer?
E horizon - zone of leaching
What is the fourth soil layer?
B horizon - subsoil
What is the fifth soil layer?
C horizon - weathered parent material (such as bedrock)
Is topsoil formation renewable?
No, it is nonrenewable
What affects the rate in which soils form?
Parent material, location, erosive forces, exposure (to wind & water), etc
True/False: In LDC’s, it’s often cheaper to farm new land rather than use pesticides & fertilizers (aka the Green Revolution)?
True
Does sand or clay drain faster?
Sands, because they have macropores that have more space between the pores that water can more easily flow through
Does sand or clay hold more water?
Clay does, considering the fact that clay has micropores that are much closer together and have less space in between, which prevents the flow of water to exit
What are the 5 soil formation factors?
1) Parent material
2) Climate
3) Topography
4) Biological Activity
5) Time
What are the 6 components of soil?
- Sand & Gravel
- Silts & Clays
- Dead Organic Material
- Soil Fauna & Flora
- Air
- Water
T/F: Soils have gradient boundaries
True, they are linked to community types
What are the 3 categories of food resources?
Grains/vegetables, meat & milk, fish
Landscape
Collections of ecosystems
National Park
Higher level & priority of protection, “hands off”
National Forest
The preservation of timber (in managed ways)
What does the shape of a triangle age-gender profile suggest?
That it suggests that populations are increasing
What does the shape of a petal age-gender profile suggest?
That populations are stable/stabilizing
What does the shape of a ice cream cone age-gender profile suggest?
That populations are decreasing
T/F: A correlation has been found between the demise of civilizations & the loss of soil resources
True
What is the CITES treaty?
An international agreement that helps protect endangered animals and plants from the threats of illegal exports/imports
What are the 4 basic texture classes?
1) Loams (best for agriculture)
2) Sands (good for building sites)
3) Silts
4) Clays
What did the Green Revolution consist of?
New crop hybrids, rotational cropping, fertilizers & pesticides, mechanization
What are the vowels for the soil layers?
OAEBC
What does parent material consist of? (5)
Bedrock, Alluvium, Loess, Volcanic Material & Glacial Till
What are GMO’s?
Genetically Modified Organisms, which is when you take a gene and with good traits to create your breeding stock
What are some soil conservation techniques to help prevent water erosion?
Reduced tillage, contour farming, terracing, grassed waterways, siltation fences, phased development
What are some soil conservation techniques to help prevent wind erosion?
Reduced tillage, strip cropping, windbreaks, cover crops, mulches, phased development
Why should we use fertilizers? (3)
- Produces high-yielding plant varieties
- Creates crop production on marginal lands
- Cycling of nutrients
What was the blue revolution?
The discovery that the oceans held lots of food sources
T/F: 11% of the Earth’s land is farmable
True (this applies for croplands)
What is restoration ecology?
To repair or reconstruct ecosystems damaged by humans/natural forces (constructed wetlands)
What are some common characteristics of deserts?
Low niches, low populations, high environmental resistance, low precipitation levels, evaporation greatly exceeds precipitation, drastic temperature changes from day to night, very cold at night
How many inches of annual precipitation do deserts give off?
Less than 10 inches
T/F: Deserts can be easily be disturbed & can last generations
True
How are grasslands characterized?
Areas that are too dry to farm and too dry for trees
Grasslands have annual _____?
Precipitation
Grasslands have what type of soils?
Rich soils
Do grasslands have low, moderate or high biodiversity?
Moderate
T/F: Grasslands are the most productive cropland
True, this is due to their rich soils
Tundras have low amounts of liquid ______?
Precipitation
Tundras are adapted to what?
Lack of sunlight + water, freezing temperatures & constant wind
T/F: Tundras can be easily disturbed
True
T/F: Tundras aren’t slow to recover
False, they can be disturbed easily
What is the difference between swamps, marshes & bogs?
Swamps contain trees, marshes do not, bogs have waterlogged soils
Tropical rainforest characteristics
High precipitation, warm temperatures, high biodiversity, lots of niches, complex food webs
