Physical Geography (GEOG 1301.01)

Lecture 11

Chapters 20-21

Chapter 20: Terrestrial Biomes

Important Concepts

CO2-Rich atmosphere will have dramatic effects on ecosystems.

Main topographic barrier separating species are the oceans (and climatic).

Ecotone is an area of tension (edge areas generate biodiversity)

Plants reflect Earth’s physical systems (page 630)

Dominant vegetation identifies each biome (forest, savanna, grassland, shrubland, desert and tundra)

270,000 plant species

Natural vegetation = ideal potential, there are no unaltered biomes

Humans have perpetuated large-scale transition communities (grassland and forest)

More than ½ of earth’s original forests are gone (gone by 2050.)

Species extinction = 1,000-30,000 annually

Why? Pollution, loss of habitat, grazing, poaching and collecting

60% of extinction from rain forest clear-cut

Review: community, ecosystem, habitat and niche

Key Terms

Biogeographic realm

Ecotone

Terrestrial Ecosystem

Biome

Formation classes

Equatorial and Tropical Rainforest (most diversity, ½ of remaining forests, vertical niches, canopy biomass, 1% of sunlight reaches forest floor, poor soils, recycling system for atmospheric carbon dioxide)

Tropical Seasonal Forest and Scrub

Topical Savanna

Midlatitude Broadleaf and Mixed Forest

Needleleaf Forest and Montane Forest

Temperate Rain Forest

Mediterranean Shrubland

Midlatitude Grasslands

Deserts

Arctic and Alpine Tundra

Chapter 21: Earth, Humans and the New Millennium

Important Concepts

Human population over 6 billion

37% in 2 countries (China and India)

Double in 50 years

Planetary Impact = Population x Affluence x Technology

Carrying capacity of planet = 20 billion

KNOW: 12 Paradigms for 21^st Century

Key Terms

Gaia Hypothesis

Assignment Discussion (nothing to write down)

Answer this question: Based upon the topics of this class, what is your prediction for life on earth in the future and what do you think that you could do to make it better?