Biodiversity of World Biomes

Field Explorations with

Dr. Jacqueline S. McLaughlinand

Dr. Stam M. Zervanos

Overview and Purpose

• Immerse students in the study of biodiversity through a blended delivery of disciplinary knowledge (pre-trip Web-based assignments, lectures and discussions in the field, post-trip assignments) and an experiential field study.

• Learn the principle ecological and evolutionary mechanisms leading to this biodiversity.

• Help students better understand the importance and challenges of sustaining the world environments by allowing them opportunities to gain first-hand knowledge of the geography, economics, sociology, politics, history, and culture of people in locations visited.

• Encourage students to become advocates for protecting biodiversity.

The Biosphere

• In 2002 about 1.7 million species had been discovered and identified by biologists.

• The sum of Earth’s ecosystems, the Biosphere encompasses all parts of the planet inhabited by living things.

Terrestrial Biomes

The term biome refers to a major type of terrestrial ecosystem that typifies a broad geographical region.

• tundra (artic and alpine)

• temperate rain forest

• temperate deciduous forest

• desert

• taiga (coniferous, needle leaf or boreal forests)

• temperate grassland

• chaparral (Mediterranean)

• tropical rain forest

• savanna

• polar ice

Distribution of Major Terrestrial Biomes

Biodiversity

• For at least 3.8 billion years, a complex web of life has been evolving here on Earth.

• Biodiversity - short for biological diversity - is the variety of all living organisms and their interactions. Scientists often speak of three levels of diversity - species, genetic, and ecosystem diversity.

Species

Genetic

Ecosystem

Importance of Biodiversity

Reasons human cultures value biodiversity:

The rich variety of species in biological communities gives us food, wood, fibers, energy, raw materials, industrial chemicals, and medicines, all of which pour hundreds of millions of dollars into the world economy each year.

Moreover, people have a natural affinity for nature, a sense of “biophilia,” wherein they assign a non-utilitarian value to a tree, a forest, and wild species of all kinds (E. O. Wilson).

Importance of Biodiversity

Pollination For every third bite you take, you can thank a pollinator.

Air and Water PurificationBiodiversity maintains the air we breathe and the water we drink.

Climate ModificationBy giving off moisture through their leaves and providing shade,

plants help keep us and other animals cool.

Drought and Flood ControlPlant communities, especially forests and wetlands, help control

floods.

Cycling of NutrientsThe elements and compounds that sustain us are cycled endlessly

through living things and through the environment.

Importance of Biodiversity

HabitatNatural ecosystems provide habitat for the world’s species (forests,

wetlands, estuaries, lakes, and rivers – the world’s nurseries).

FoodAll of our food comes from other organisms.

Natural Pest Control ServicesNatural predators control potential and disease-carrying organisms

in the world.

Drugs and MedicinesLiving organisms provide us with many drugs and medicines.

Biodiversity Threatened

• The current threat to biodiversity, and thus to the biosphere as we know it, stems primarily from expanding human populations and increased human consumption of natural resources.

THE WORLD POPULATION HAS TRIPPLED IN THE LAST 70 YEARS.

Based on the present rate of population growth. One could conservatively predict the population to be by

the year: 2,050 AD 12 Billion ???2,100 AD 24 Billion ???2,150 AD 48 Billion ???2,200 AD 96 Billion ???

2,250 AD 192 Billion ??? 2,300 AD 384 Billion ???

http://www.edu.ue-foundation.org/worldpop.html

Biodiversity Threatened

• While the population of a species is typically set by predation, resources, disease and geography, the human population growth curve has never been restricted. As a result, no species can compete with humanity. This is our reality.

Biodiversity Threatened

Human population explosion continues while:

As much as 34% of the world’s fish species (51% of freshwater species), 25% of amphibians, 24% of mammals, 20 % of reptiles, 14% of plants, and 12% of bird species are under threat of extinction, according to the 2000 joint study by the World Conservation Union and Conservation International and a 1999 study by the World Wildlife Fund.

As many as a quarter of 1 percent of the species in the world’s tropical rainforests (roughly 9,000-26,000 species) are being extinguished or doomed to early extinction each year (25-71 species per day).

According to estimates from the Food and Agricultural Organization and the United Nations Programme, 76,000 square kilometers of tropical rainforest a year--the size of West Virginia or Costa Rica-- is being permanently cleared or converted into shifting-cultivation cycle. Tropical rainforests cover only 7% of the Earth’s land surface, but contain more than half the species in the entire world.

During the past 150 years, humans have directly impacted and altered close to 47% of the global land area according to the World Atlas of Biodiversity: Earth’s Living Resources for the 21st Century released by the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) in August 2002.

Under one bleak scenario, biodiversity will be threatened on almost 72% of Earth's land area by 2032.

Factors Leading to Biodiversity Loss

Multiple forces entrained by human activity reinforce one another and force species down. These factors are summarized be conservation biologists under the acronym HIPPO:

Habitat Destruction

Invasive Species

Pollution

Population

Overharvesting

The prime mover of the incursive forces around the world is the second P in HIPPO – too many people consuming too much of the land and sea space and the resources they contain.

- E. O. Wilson, The Future of Life

The Galapagos Islands

Alaska

Australia

Costa Rica

Biodiversity Online

http://www.clat.psu.edu/biodiversity/