What is Biodiversity? How much variety is there? What is Biodiversity? How much variety is there?

Introduction ◦ Biodiversity is the number of different species in an area. ◦ It is very difficult to estimate the total diversity on Earth because many areas of the planet have not been studied. ◦ Some scientists believe that the deep oceans alone could contain 10 million new species!!

Objectives ◦ Find out the factors affecting biodiversity ◦ Learn about the value of biodiversity ◦ How diversity is important to the gene pool ◦ What extinction is and its causes ◦ How we can protect our biodiversity

Factors Affecting Biodiversity ◦ Area ◦ Climate ◦ Niche Diversity

Area ◦ Within an ecosystem, a large area will contain more species than a small area. ◦ For example, if you were counting frogs you would find that a large pond had many more frogs than a small one.

Climate ◦ Warmer climates are found toward the equator and as a rule of thumb the number of species increases toward the equator. ◦ Tropical rain forests found near the equator are some of the most diverse ecosystems in the world. ◦ This can be due to the fact that food can be found year round in these regions since the plants grow all year instead of just one season.

Niche Diversity ◦ Coral reefs are home to 20 percent of the world's saltwater fish species, but they make up less than 1 percent of the ocean's area. ◦ A reef provides a lot of different niches for organisms that live under, on, and among coral. ◦ This enables more species to live in this area than a more uniform area such as a sandbar.

CHECKPOINT: WHAT IS ONE POSSIBLE REASON THAT TROPICAL REGIONS HAVE THE GREATEST DIVERSITY?

The Value of Biodiversity ◦ There are many reasons why preserving biodiversity is important. It can be something as simple as its beauty or as complex as : ◦ Economic Value ◦ Value to the Ecosystem ◦ Genepool Diversity

Economic Value ◦ Many plants and animals are essential to human survival. ◦ They provide oxygen, food, clothing, medicine, and building material. ◦ Some plants in recent years have been found to combat certain types of cancer. ◦ No one knows how many other useful species have not been identified. ◦ Some companies even make money by showing off the beauty of nature like safari groups, rainforest tours, and camp grounds.

Value to the Ecosystem ◦ All species in an ecosystem are connected in one way or another. ◦ One species may depend on another for food like the hawk needs a field mouse for food. ◦ Another species depends on one for shelter. For example the squirrel needs a large species of tree to nest in. ◦ Some species play a very important role in the survival of many species. ◦ This is known as the keystone species. ◦ If the keystone species disappears the entire ecosystem will change.

Gene Pool Diversity ◦ The organisms in a healthy population have a diversity of traits. ◦ This traits are determined by genes. ◦ Genes are information within cells that carry on the hereditary information. ◦ They are what determine why you have your hair color, eye color, and height. ◦ But some genes are different from others in the species. This is what makes up the total gene pool. ◦ Species that have a small gene pool have a hard time adapting to environmental change. ◦ Humans have one of the largest gene pools and can adapt very quickly to changing environments.

CHECKPOINT: WHAT DO AN ORGANISM'S GENES DETERMINE?

Extinction ◦ Extinction is the disappearance of all members of a species. ◦ Some examples of extinct species are passenger pigeon, Carolina parakeet, Zanzibar leopard, and the golden toad. ◦ Extinction is a natural process, but the number of extinct animals has been increasing dramatically. ◦ Endangered species are species that could become extinct in the near future such as the Siberian tiger. ◦ Threatened species are species that could become endangered in the near future such as the whooping crane. ◦ Many factors can contribute to extinction including: habitat destruction, poaching, pollution, and exotic species.

Habitat Destruction ◦ Habitat destruction is the loss of natural habitat. ◦ This can be through human intervention or natural disasters. ◦ Plowing grassland, clearing forests, and filling in wetlands are all parts of human intervention. ◦ Hurricanes, wildfires, and tornadoes are some of the most destructive natural disasters. ◦ Habitat fragmentation is breaking larger habitats into smaller, isolated pieces. ◦ This can be building roads or walls which animals can be injured trying to cross to get to more resources they need to survive.

Poaching ◦ Poaching is the illegal killing or removal of wildlife. ◦ Many animals become endangered if their fur, skin, teeth, horns, or claws are desirable. ◦ Some animals are also captured and sold as pets. These include tropical fish, parrots, snakes, and tortoises. ◦ Plants can even be dug up and sold as houseplants while others can be sold as medicine.

Pollution ◦ Pollution is very harmful toward plants and animals. ◦ Pollutants, substances that cause pollution, can reach animals through the air, water, or food. ◦ Some pollutants can also settle in the soil and be absorbed by plants. ◦ Pollutants may kill or weaken organisms. They are also known to cause birth defects.

Exotic Species ◦ Introducing exotic species into an ecosystem can threaten biodiversity even though you are adding to the biodiversity initially. ◦ New species can often outcompete the native species for food. This will cause food shortages. ◦ An example is the Asian carp which has been accidentally introduced to eastern rivers in North America. ◦ The Asian carp is causing a lot of stress on native species such as the catfish, small mouth bass, and walleye. ◦ The Asian carp can reproduce much faster than native species so their numbers are doubling and tripling each year since they have no natural predators in the area. Food is running short for the other species.

Protecting Biodiversity ◦ Many citizens are striving to protecting our biodiversity ◦ Scientific and legal approaches are used to help strengthen and heal species that have been hurt. ◦ These programs include captive breeding, laws and treaties, and habitat preservation. ◦ What can you do to help biodiversity?

Captive Breeding ◦ Captive breeding is the mating of animals in zoos or wildlife preserves. ◦ One of the largest programs can be found in China where they are working to bring back the Panda population. ◦ In these programs scientists often care for the young to increase survival rate. The offspring are then released back into the wild. ◦ Captive breeding saved the California Condor which was down to ten adult members. Now there are more than one hundred found in zoos. ◦ Some condors have been released back into the wild, but the program is very costly at $20 million dollars.

Laws & Treaties ◦ Laws and treaties are usually used to protect individual species or endangered species in general. ◦ Many nations have made it illegal to sell or trade products made from endangered species such as the United States Endangered Species Act of ◦ The most important treaty toward protecting biodiversity is the Convention on International Trade in Endangered Species in ◦ This treaty included 80 nations and lists over 700 protected species. ◦ Poaching makes these laws difficult to enforce.

Habitat Preservation ◦ Habitat preservation is the most effective way to preserve biodiversity. ◦ In this instance you are protecting the whole ecosystem instead of just single species. ◦ Many countries have set aside wildlife preserves as parks and refuges. In 1872 Yellowstone National Park was the world's first national park. ◦ To be effective however, reserves must contain a diverse ecosystem so this requires them to be very large. ◦ Yellowstone National Park is 3469 square miles.

Review Questions ◦ What are three factors that affect biodiversity? ◦ List four possible causes of extinction. ◦ Give an example of a legal approach and a scientific approach to preventing extinction. ◦ Which are the most biodiverse ecosystems on Earth? ◦ Identify three ways in which biodiversity is important.

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