Biodiversity Describe the diversity of species types on Earth, relating the difference Between known and estimated numbers. List and describe 3 levels of biodiversity. Explain 4 ways in which biodiversity is important to ecosystems and humans Analyze the potential value of a single species.

Why Do I Need To Know This? Because large amounts of our medicines and products come from plants and animals and will not be available to us if the plants and animals go extinct. Because humans are causing extinction at a rate 1,000 times faster than it has ever occurred in the past. Because as our population grows, we continue to destroy habitat that is necessary for plants and animals to survive.

What is Biodiversity? Every day somewhere on Earth a species becomes extinct. Extinction is when the last member of a species dies. Biodiversity – refers to the number and variety of different species in a given area. The study of diversity starts with cataloging all of the species on Earth. About 1.7 million species are known and of those many of then are insects. Many scientist estimate that there are greater than 10 million different species on Earth. A species is considered known when they have been cataloged and described scientifically. In general the smaller an organism is the harder it is to study and the lees well known it is.

Levels of Diversity Biodiversity can be studied at 3 different levels Species diversity refers to all the differences between populations of species as well between different species. This is what is meant most often by the term biodiversity. Ecosystem diversity refers to the variety of habitats, communities, and ecological processes within and between ecosystems. Genetic diversity refers to all the different genes contained with in all the members of a population. Gene is a piece of DNA that codes for a specific trait that can be inherited by that Organisms offspring.

Benefits of Biodiversity Biodiversity affects sustainability of an ecosystem and its populations. Biodiversity is ensures a healthy ecosystem and balances cycles of energy and nutrients. Keystone species – species that are critical to the functioning of an ecosystem. Keystone What happens to the arch if the keystone is removed? How is the arch similar to a food web?

Biodiversity At Risk We are now living during an era of mass extinction. In the past, there have been 5 periods of mass extinction that occurred naturally. These typically resulted from mass catastrophes such as meteor impacts.

Genetics and Population Survival The level of genetic diversity within a population is critical for survival. The greater the gene pool the more likely the population will be able to survive environmental changes or pressures. Small isolated populations are often the first to die off.

Extinction When the last member of a species dies. Mass Extinction – the loss of many species over a relatively short period of time. Earth has experienced several mass extinctions and it takes millions of years for Biodiversity to rebound.

Current Extinctions Scientist warn that we are in the midst of another mass extinction. Between 1800 and 2100 up to 25% of all species on Earth may become extinct. Species with small populations, that migrate, need large amounts of space, special habitats, or that are exploited by humans are at risk of extinction. Endangered Species – Species that are likely to become extinct if protective measures are not taken immediately. Threatened Species – Species that is declining in numbers and is likely to become endangered if it is not protected.

How Do Humans Cause Extinctions?

How Are Humans Causing Extinction? Humans are causing extinction in 3 ways: Habitat Loss Hunting/Poaching Introducing Exotic Species Of the 3 ways, habitat loss is the most common and most damaging method of causing extinction. This is because the human population is growing by 220,000 people everyday, habitat loss is happening on a massive and global scale.

Habitat Destruction and Fragmentation As human populations grow, more land is being used to build homes and to harvest resources. It is estimated that 75% of extinctions that are now occurring are due to habitat loss.

Habitat Destruction Whenever humans take over new land for use, they clear it and wipe out the species living on it. Habitat loss is particularly hard on large animals, as they often require large amounts of area for their habitats. Although habitat loss is a massive problem in developed nations, it is also a major problem in developing nations because their populations are growing more rapidly and most of the world’s species live in those nations. The rain forests for example, contain about 50% of all the world’s species, yet only cover 7% of the world’s land.

Invasive Exotic Species Exotic Species - a species that is not native to a particular region.

Exotic Species Exotic species are species that are not native to an area. Introducing exotic species to an area is particularly harmful to an environment as they may not have any predators or animals in the area may not have any defenses against them. Consequently, they can destroy an entire ecosystem very quickly. This is a major cause of extinction in the developed nations, as we have imported thousands of species from around the world. An example is the melaleuca tree, which was brought to Everglades in the early 1900s. It is now spreading at a rate of about 50 acres a day, wiping out species that depend on that wetland ecosystem.

Harvesting, Hunting, Poaching Thousands of rare species are hunted or harvested to extinction. These organisms are sold as pets, houseplants, wood, food, or herbal medicine. Hunting and harvesting are activities that are regulated by the government. Poaching is the illegal hunting or harvesting of organisms.

Hunting Unregulated hunting (poaching) can also cause extinction. For example, between 1900 and 1920, the American passenger pigeon became extinct even though there were over 2 billion passenger pigeons alive in 1900! Although a major problem in the past for the industrialized nations, unregulated hunting is not a major cause of extinction today because the government regulates the amount of animals to be killed. Unregulated hunting, is, however a major cause of extinction in developing nations. For example, the number of wild chimpanzees in Africa has dropped from over 100,000 to around 6,000 in just the last 10 years! Poaching is particularly devastating because the poached animal is often killed for just 1 thing and the rest of it is discarded.

Pollution Chemicals and other pollutants are making their way into the food webs. The long term affects of pollution on the ecosystem is unknown.

Areas of Critical Biodiversity Endemic Species – species that are native to and found only within a limited area. Biologist use the number of endemic plant species to as an indicator of overall biodiversity.

Rainforest cover less than 7% of the Earths surface but has half of the worlds species.

Coral reefs and coastal ecosystems make up a fraction of the environment but contain the majority of the biodiversity. Reefs provide all sorts of things for humans including 375 billion dollars in tourism revenue. Nearly 60% of Earths coral reefs are threatened by human activities.

Islands when they emerge from the sea are colonized by a limited number of species from the main land. The colonizing species may then evolve into several island species. Thus islands have their own endemic species. These types of ecosystems are very vulnerable to invasive species.

Biodiversity Hotspots Threatened areas of high biodiversity are called biodiversity hotspots. 25 hotspots have been identified. Most hotspots have lost 70% of their original vegetation.

Biodiversity in the United States There are 3 biodiversity hotspots in the US Including the Florida Everglades, California coastline region, Hawaii, The Midwest Prairies, and the forest of the Pacific Northwest. The US has a large number of freshwater aquatic organisms and plant species.

The Value of Biodiversity Although extinction is a natural process (over 99% of all species that ever existed on the planet have gone extinct), there are 3 main reasons why we should preserve species. They are: Saving species can preserve an entire ecosystem; Humans depend upon species for many practical uses; Ethical and aesthetic reasons.

Saving Species Preserves Ecosystems Species, along with the abiotic factors, are what make up ecosystems. Each species performs a vital role in maintaining a healthy ecosystem and plays a part in the cycling of materials and the transfer of energy. Every time a species disappears it alters the ecosystem and makes the ecosystem less stable. Some species are perform such an important role in an ecosystem that the entire ecosystem would collapse without it.

Human Benefits of Biodiversity Medical – ¼ of the drugs prescribed in the US come from plants. All antibiotics come from fungi. Industrial – New chemicals and products like rubber. Agricultural – New crop varieties and hybrids – crops developed by combining genetic material from other populations. Clothing – Materials like cotton. Shelter – Building materials. Aesthetics – Personal enjoyment like ( pets, camping, hiking, biking, picking flowers, or wildlife watching). Recreation (Ecotourism) – Form of tourism that supports the conservation and sustainable development of ecologically unique areas.

Practical Uses of Species Many species have practical uses for humans today. Over 40% of all prescription drugs in the United States were developed from plants and animals. Diseases such as cancer, heart attack, and strokes, all of which are fatal, are all treated with drugs developed by endangered plants and animals. You have about a 25% chance of getting cancer, 50% chance of having a heart attack and about a 33% chance of having a stroke! Additionally, since we rely on plants an animals for food, the loss of biodiversity will affect the amount of overall food that is available for us to eat! And, the lack of biodiversity will make the chance of our food supply becoming more at risk to disease and pestilence even greater!

Ethical and Aesthetic Reasons Many people believe for religious and ethical reasons that humans are to maintain the world, not destroy it. By causing extinction, we are removing objects of interest and curiosity on the only known planet to develop life.