GLOBAL ENVIRONMENTAL CHALLENGES

What is biodiversity?

The variety of life on Earth, including species diversity, community/ecosystem diversity, and genetic diversity. [GLSD3401_0...versity(1) | PDF]

What are two key measures of biodiversity?

Number of species and species evenness

What is a keystone species?

A species that plays a vital role in the survival of other species, e.g., predators that control herbivores

What are umbrella species?

Large animals needing large unspoiled habitats (e.g., elephants, tigers). Protecting them protects other species

How many species have been described, and how many may exist?

~2 million described; 5–30 million may exist

Which groups are most species‑rich?

Flowering plants and insects

What is biological wealth?

Biota plus ecosystems—natural capital sustaining human life and economies.

What is intrinsic value of biodiversity?

The inherent value of species independent of human use. Supported by major religions.

What is instrumental value?

The utilitarian value of biodiversity for food, raw materials, medicine, etc.

What is a cultivar?

A highly selected strain with minimal genetic variation and high yield.

Why are wild species important for crop breeding?

They provide genes for vigor, resistance, and tolerance

What percentage of global food comes from 3 crops?

Wheat, maize, and rice provide 50%

What is a genetic bank?

Living organisms storing gene pools of species (e.g., seed banks, zoos).

Give one example of medicinal value of biodiversity.

Paclitaxel (Taxol) from yew trees treats several cancers.

What does HIPPO stand for?

Habitat destruction, Invasive species, Pollution, Population, Overexploitation.

What percentage of extinctions are caused by habitat loss?

About 36%.

What is habitat fragmentation?

Splitting habitats into small patches, increasing extinction vulnerability

Define invasive species.

Non‑native species that thrive, spread, and harm native species.

What is overexploitation?

Harvesting species faster than they can reproduce.

What is the ecosystem approach to conservation?

Protecting habitats that support multiple species rather than focusing on individual species.

What is carrying capacity?

The number of people an area can support sustainably with given technology.

What did Malthus propose about population growth?

Population grows geometrically, food supply arithmetically → inevitable shortages.

What did Boserup argue about population?

Population growth drives agricultural innovation (“necessity is the mother of invention”).

What was Julian Simon’s viewpoint?

Human ingenuity expands resources; scarcity drives innovation; resources are “economically indefinite.”

What is Paul Gilding’s main idea?

“The Earth is full”—we are exceeding the planet’s limits and risking collapse.

What is Peter Diamandis’s main idea?

Technology and exponential innovation will create abundance in the future.

What do Neo‑Malthusians believe?

Resources are finite; exceeding limits leads to catastrophe.

What do economic optimists believe?

Innovation, markets, and institutions overcome scarcity.

What do distributionists believe?

Scarcity results from inequality in resource distribution, not absolute limits.

What is Homer‑Dixon’s viewpoint?

Environmental thresholds and system interdependence can cause adaptive failure despite technology

What are examples of non‑renewable vs. renewable energy?

Non‑renewable: fossil fuels; Renewable: wind, biomass, hydropower, solar.

What factors does sustainability connect?

Food, society, economy, politics, energy, climate.

Where did the Agricultural Evolution begin?

In the Fertile Crescent: Tigris–Euphrates (Iraq), Nile valley (Egypt), Levant (Jordan & Palestine)

What traits were selected for in plant domestication?

Big‑seeded, edible, early‑germinating, self‑pollinating, easy to store.

Out of 148 large herbivores/omnivores, how many became domesticated?

Only 14

Why are many species not domesticable?

Finicky diet, slow growth, don’t breed in captivity, nasty disposition, hard to herd, panic easily, solitary or territorial nature.

What are the major domesticated plants?

Wheat, maize, rice, barley, sorghum, soybean, potato, cassava, sweet potato, sugar cane, sugar beet, banana. (80% of global production)

What are the five major domesticated animals?

Horse, cow, pig, sheep, goat

Why was the Fertile Crescent ideal for domestication?

Mediterranean climate, wild wheat stands, many self‑pollinating plants, 32 of 56 large seeded grasses, suitable large animals.

Why did agriculture spread more easily East–West than North–South?

Similar climates along longitude; major climatic differences across latitude hindered spread in the Americas and Africa.

Why was crop exchange limited in the Americas?

Mountains and tropical lowlands blocked movement; crops like maize took thousands of years to spread and adapt.

What did agriculture enable in early societies?

Labor for infrastructure, conquest, and tech development; stable food supply; population growth

How did animals enhance human capabilities?

Provided protein, plowing power, transport (horses, camels), fibers, fertilizer; greatly magnified human power

What were major outcomes of sedentary living?

Shorter birth intervals, population growth, grain storage, emergence of specialists (kings, priests, soldiers, artisans)

What major impacts came with the Agricultural Evolution?

Population growth, higher per‑capita energy use, habitat destruction, biodiversity distortion, epidemics, vulnerability to climate.

What are key differences between farmers and pastoralists?

• Farmers: warm/humid regions, depend on crops, sedentary, nuclear families.

• Pastoralists: cool/arid regions, depend on herds, mobile, looser family structure.

How did agriculture contribute to state formation?

More food → population growth; people tied to land; division of labor; emergence of elites; vulnerability → walled settlements → kingdoms.

What was the social hierarchy in early agricultural societies?

Elite → conquered/exploited (peasants, slaves, workers). Tribute and conquest sustained elites

Why did Eurasia advance more quickly?

Best domesticable plants/animals; East–West axis; large populations enabling governments, literacy, technology

What advantages did European conquistadors have?

Horses, steel, ships, political organization, and written historical knowledge.

Why were Europeans resistant to many diseases?

Long exposure to animal agriculture led to immunity to diseases like smallpox, measles, influenza.

What percentage of Native Americans were killed by European diseases?

About 95%

Why not Mesoamerica?

Few domesticable animals; slow maize domestication

Why not the Middle East?

Environmental degradation from unsustainable agriculture

Why not East Asia?

Large stable empires → less external pressure → technological stagnation.

How did agriculture change resource and population patterns?

More people in smaller areas → intensified land use, rigid boundaries, increased global interdependence.

What is the difference between weather and climate

Weather = short‑term atmospheric state; climate = long‑term average over decades to millennia

Which climatic element varies most regionally: temperature or precipitation?

Precipitation shows very strong regional variation

What are the three categories of climate impacts?

• Direct impacts (extremes → human suffering)

• Risks via ecological/biophysical systems

• Social & economic disruptions → human suffering

What aspects of agriculture does climate change affect?

Growing season length, arable land, number/composition of species.

Why was early agriculture highly climate‑dependent?

Low technology, heavy reliance on farming, limited institutions to buffer shocks.

What time scales does climate change operate on?

Multi‑millennial, multi‑centennial, multi‑decadal

In China, what climatic factors influenced pastoralist vs agriculturalist conflict?

Temperature shifts affected agriculturalists; precipitation shifts affected pastoralists

What percentage of population collapses occurred during climate deterioration?

About 90%

What were dominant triggers of population collapses?

Malthusian checks: famine, war, epidemics..

What chain of impacts can link climate change to conflict?

Climate change → population growth pressure → resource shortage → conflict (immediate cause) + root causes

What determines land carrying capacity in agriculture?

Total cultivated area × max yield per unit × harvest index.

Why are modern societies vulnerable to climate change?

High specialization, monoculture, fossil‑fuel dependence, dense populations, fragile infrastructure, low‑income coastal populations, global environmental change

What is a secular cycle?

A long‑term pattern of rising and falling population, resources, and social complexity over centuries.

What drives the phases of the business cycle?

Fluctuations in economic activity: expansion, boom, peak, downturn, recession, and trough.

How does climate change influence historical population cycles?

Good climate increases food production and population; bad climate causes famine, disease, and population decline.

What is land carrying capacity?

The maximum population size that available land and resources can sustainably support.

According to Malthus, what prevents overpopulation?

Preventive checks (birth control) and positive checks (famine, disease, war).

According to Boserup, what increases carrying capacity?

Human innovation and increased manpower, which stimulate technological and agricultural improvements.

What happens when population pressure becomes too high?

Famine, epidemics, wars, and migration increase, reducing population size.

What is the normal per capita grain output threshold?

250–300 kg per person.

What per capita grain output indicates overpopulation?

200–250 kg per person.

What per capita grain output indicates extreme overpopulation?

Below 200 kg per person.

What major factors reduce population growth?

Birth control, Malthusian catastrophes, and reduced per‑capita resource consumption.

What technological changes historically increased carrying capacity?

Domestication, improved tools, animal power, canals, and introduction of American crops.

Why did medieval Europe become vulnerable before the Black Death?

High social complexity, specialization, forest clearance, and dependence on tightly connected systems.

What is Phase V in the medieval complexity model?

A productive but fragile landscape created by widespread forest clearance and specialization.

What are key vulnerabilities of modern societies to climate change?

Stressed food systems, monocultures, dense populations, complex infrastructure, coastal dependence, global environmental change, and international tensions.