ENSCI 100 Final Exam Study Guide
Questions And Answers 2023 Update
land Use and Biological Conservation Slides: -Correct Answerstarting in 2010, about
... [Show More] wildlife in the Serengeti as threatened by -Correct Answer-a
commercial highway
- blocked plan, and an alternative route that wrapped around the southern Serengeti
was planned instead.
(would cause: habitat fragmentation, makes habitats smaller, and prevents movement
of organisms between habitats.)
In 2016, Serengeti was threatened by -Correct Answer-an oil pipeline
benefits of biodiversity -Correct Answer-* critical to food security
* sources of new drugs and medicines
* Ecosystems services that society relies upon
* Ecotourism is essential to many economies
* Humans have a connection with nature and green spaces provide needed stress relief
Organisms provide: -Correct Answer-drugs and medicines
About half of today's pharmaceuticals are derived from -Correct Answer-chemical
compounds in wild plants.
ex: pineapples
Bioprospecting -Correct Answer-searching for organisms that might provide new foods,
medicines, or other products, including animals that are endangered
ex: amphibians, sharks, crabs
Biodiversity provides ecosystem services: -Correct Answer-* Food, fuel, fiber, and
shelter
§ Air and water purification
§ Waste decomposition
* Climate stabilization (reduction in droughts, floods, etc.)
* Pollination of plants
* Controlling pests and diseases
* Maintaining genetic diversity of crops & livestock
* Cultural and aesthetic benefits
Removal of which of the following species will result in the greatest changes in an
ecological system? -Correct Answer-"keystone species" (e.g a top predator) bc if lost,
consequences cascade down the entire food chain.
ex:
wolf, starfish, sea otter
If an "ecosystem engineer " is lost -Correct Answer-the entire structure of an ecosystem
can change (physically).
ex: elephants- change vegetation and spread
seeds in dung
Ecotourism present in -Correct Answer-Tanzania & Costa Rica
Edward O. Norton -Correct Answer-"human beings share an instinctive love for nature
and feel an emotional bond with other living things."
this is called biophilia
Habitat loss -Correct Answer-is the greatest threat to biodiversity today.
Humans have altered, degraded, or destroyed habitat through ... -Correct Answer-urban
sprawl, farming, grazing, clearing forests, and damming rivers.
Forests cover ___________ of Earth's land surface. -Correct Answer-30%
Deforestation leads to -Correct Answer-biodiversity loss, soil degradation, and
desertification, as well as contributing to climate change.
Satellite analysis conducted by the Food and Agriculture Organization (FAO) of the
United Nations concluded that we are eliminating -Correct Answer-7.6 million hectares
of forest each year.
about 2% of U.S. Forest acreage is harvested for timber each year.
Overall, timber harvesting has been stable in developed countries in the past halfcentury, but has doubled in developing countries due to industrial technologies.
The deforestation is spurred by a desire to: -Correct Answer-expand human settlements
and agriculture
boost economic growth
provide fuelwood for heating and cooking needs.
(Brazil example of this)
In Southeast Asia, swaths of tropical rainforest are being cut to establish palm oil
plantations. -Correct Answer-Palm oil is used as a biofuel and is also found in many
processed foods.
Forest loss worsens climate change because it released -Correct Answer-carbon
dioxide
and less vegetation remains to soak it back up.
forest loss solution: -Correct Answer-empowering local people to act as stewards for
their forests.
paying countries to preserve forests
Developing nations receive conservation concessions
developed countries receive carbon emissions offset credits.
ecosystem-based management -Correct Answer-where managers try to decrease
impacts on the ecosystem and its processes.
Adaptive management -Correct Answer-involves testing different approaches and trying
to improve methods over time.
umbrella species -Correct Answer-protected under the Endangered Species Act leads
to the preservation of its habitat and all of the other organisms in its community
-Correct AnswerBiodiversity hotspots -Correct Answer-are regions that support a great number of
species that are found nowhere else
The Antiquities Act of 1906 -Correct Answer-gave the president authority to declare
selected public lands as national monuments.
The National Park Service was created in ?? administered?? -Correct Answer-1916 to
administer the 408 total parks and monuments.
national wildlife refuge -Correct Answer-are meant to be havens for wildlife.
Wilderness Act when did it pass and what is it? -Correct Answer-1964: allowing some
federal areas to be designated wilderness areas.
These areas are off-limits to development, but open to hiking and other low-impact
public recreation.
Private nonprofit groups may also purchase land for
preservation, creating "land trusts". -Correct Answer-Examples include California's Big
Sur, Jackson Hole in
Wyoming, and Maine's Mount Desert Island.
Worldwide area in protected parks and reserves has increased nearly sevenfold since
1970. -Correct AnswerBiosphere reserves contain three zones: -Correct Answer-Core: legally protected (long
term conservation of biodiversity.)
Buffer: cooperative activities ( educational, ecotourism, recreation)
Transition: agriculture & settlements
PP 1 SUMMARY: -Correct Answer-Human driven land use changes have greatly
altered the quality of habitat and extent of biodiversity.
Deforestation continues at a fast rate, especially in developing countries, but forest
management practices can provide the resources society requires while limiting
additional land use change.
Conservation measures, including landscape management, habitat protection, and park
creation are critical activities to preserve
biodiversity and to maintain societal benefits and ecosystem functions from these
natural and human altered systems.
pp2 soil: -Correct AnswerSoil is a system -Correct Answer-consisting of disintegrated rock, organic matter, water,
gases, nutrients,and microorganisms.
Often with 50% mineral matter,5% organic matter, and 45% pore space
Many fungi, called mycorrhizae, have mutualistic
relationships with plants.
The fungi provides water and nutrients, while the plant provides carbohydrates from
photosynthesis.
Bacteria and other organisms (e.g. earth worms) in the soil also contribute to
decomposition and alter nutrient availability
Soil is separated from Non-soil at the -Correct Answer-Top - vegetation, leaf litter,
organic debris
-andBottom - bedrock - parent material that supplies grains and minerals contained in soil
divide soils into zones (called Horizons) -Correct Answer-soil profile changes with time
as weathering and decomposition occur
Soil formation begins during primary succession, from the break down parent material.
§ Parent material is -Correct Answer-the base geologic material in a particular location.
This may include:
§ Hardened lava or volcanic ash
§ Sediment deposited by glaciers or flowing water.
§ Wind-blown dunes
§ Bedrock, the mass of solid rock that makes up most of the Earth's crust
Parent material is broken down into smaller particles by weathering. -Correct Answer-§
Physical weathering results from wind, rain, freezing, and thawing.
§ Chemical weathering -water or gases alter rock.
§ Biol- living things alter rock (tree roots rubbing against rock)
Weathering and the rate of organic matter accumulation are influenced by: -Correct
Answer-Climate: Warm, moist climates accelerate most weathering processes.
§ Organisms: Plants and decomposers add organic material.
§ Topography: Hills and valleys affect exposure to sun, wind,
water, and influence soil movement.
§ Parent material: Its composition influences soil formation.
§ Time: Soil formation can take centuries, decades, or millennia.
Soil Horizons/layers explained (OAEBCR) -Correct Answer-The O horizon- organic
matter
The A horizon- is topsoil
The E horizon- tends to be the most heavily leached, losing minerals like iron,
aluminum, and
silicate clay.
The B horizon- contains minerals leached from above.
The C horizon is partially-weathered parent material.
The R horizon is bedrock.
Eluviation is the process
Illuviation is the process -Correct Answer-1. of removal or distribution i.e., leaching
(zone of leaching: horizons O-E)
2. of deposition or accumulation (zone of accumulation: horizon B)
Soil can be a -Correct Answer-renewable source, but formed slowly, on timescales of
1000 years
A soil's color indicates its -Correct Answer-fertility.
§ Black or dark brown soils are rich in organic matter.
§ A pale color indicates low organic matter.
§ Soil texture is determined by the size of its particles.
Diameter(size) large to small: Gravel > Sand > Silt > Clay
SA:V listed for ratio large to small:
Clay > Silt > Sand -Correct Answer-IF DIAMETER IS larger, The SURFACE AREA IS
SMALLER
What grain type would adsorb more contaminants on its surface? -Correct Answer-Clay
Clay particles are the -Correct Answer-smallest, less than 0.002 mm in diameter.
have few (or small) pore spaces and are sticky, making it difficult for air and water to
pass through
§ Sand is -Correct Answer-the largest, between 0.05-2 mm in diameter.
allow water to pass through very quickly, requiring frequent irrigation.
§ Silt particles fall in -Correct Answer-- between clay and sand.
§ Soil with an even mixture of each particle is called loam. -Correct Answer-Loam soils
with medium- sized pores are often considered the best for agriculture.
Liebig's Law of the minimum- -Correct Answer-growth controlled by required resource in
the lowest abundance relative to need.
Cellular stoichiometry -Correct Answer-compositional ratio of cellular components (e.g.
C to N to P ratios)
plants need 16 essential nutrient elements! -Correct Answer-§ Macronutrients (large
amounts needed)
§ C, H, O, P, N, K, S, Ca, Mg
§ Micronutrients
§ Mn, Cu, Cl, Mb, Zn, Fe, B
Soil Fertility is a measure of nutrients found in soil for plant growth -Correct AnswerWays that soil gains nutrients: -Correct Answer-Nitrogen fixation:
Most N in form of stable N2
• Bacteria "fix" N and make it available as H-bound or C- bound forms
Organic matter decomposition § Animal wastes§ Weathering of parent material §
Fertilizers
What soil horizon contains topsoil and is the most productive for plants? -Correct
Answer-The A horizon
What is the ideal soil texture for plant agriculture? -Correct Answer-Soil with a mixture of
silt, clay, and sand particles (loam)
Erosion -Correct Answer-is the removal of material from one place and its transport to
another by wind or water.
§ When eroded material is left at a new location, it is called deposition.
§ Erosion and deposition are natural processes, but are
occurring at accelerated rates due to human activities.
§ Areas that are windy, sloped, have intense precipitation, or sparse vegetative cover
are the most at risk of erosion.
People make land more vulnerable to erosion in three ways: -Correct Answer-§
Overcultivating fields through over irrigation & excessive tilling (plowing).
§ Grazing rangeland with more livestock than it can support.
§ Clearing forests on steep slopes.
U.S. croplands lose about 2.5 cm (1 inch) of topsoil every 15-30 years. -Correct
AnswerMuch of the world's population lives in drylands, arid and semi-arid environments that
cover -Correct Answer-about 40% of the Earth's land surface.
Drylands are prone to desertification, a land degradation where more than 10% of
productivity is lost.
§ Wind and water erosion are the biggest causes. -Correct AnswerThe Dust Bowl prompted the US to fight erosion (what year + impact) -Correct AnswerA severe drought in the 1930s worsened the impacts, causing the region's strong winds
to erode millions of tons of topsoil.
Thousands of farmers in this area were forced off their land.
soil salinization -Correct Answer-in arid regions, irrigation water evaporates, leaving
salts behind, which builds up
prevention: reduce irrigation and switch to crop tolerant crops
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