Biodiversity

What is Biodiversity

The word biodiversity comes from the term “ biological diversity”. This diversity is the astounding array of plants and animals species that perform a vital role in the web of life. Biodiversity is the variety of all living things, including plants, animals, microorganisms, and their interrelationship. It is the genes they contain and the ecosystem they form. Biodiversity also refers to the interconnectedness between all species which means all species depend on one another for survival. Example: Food chains and webs.

Why is biodiversity important? A healthy biodiversity offers a number of natural services for free. Ecosystem services such as protection of water resources, soil formation and protection, pollination of crops, control of pests, nutrient storage and recycling, pollution breakdown and absorption, contribution to climate stability, maintenance of ecosystems and recovery from unpredictable events. Biological resources such as food, medicinal resources and pharmaceutical drugs, wood products, ornamental plants, breeding stocks, population reservoirs, future resources, diversity in gene, species and ecosystems. Social benefits such as research, education and monitoring, recreation and tourism, and cultural values.

Importance of Biodiversity in Providing Food Many plants that we depend on for food need the help of animals to reproduce. Pollinators, such as bats, bees and beetles ensure the survival of our food crops. Some plants depend on animals for the dispersal of seeds and fruits; for example, a deer might eat some berries, depositing the seeds miles away. Some seeds are covered in hooks or burrs, which catch on the fur of an animal and fall off somewhere else. This interdependence of plants and animals ensures continued food production.

Species depend on each other

Trophic Level is a position in an ecosystem’s food chain or web with each level defined by a transfer of energy between one kind of organism and another. Fourth trophic level: tertiary consumers (carnivores) Third trophic level: Secondary consumers (carnivores) Second trophic level: Primary consumers (herbivores) First trophic level: Producers (photosynthesizers)

Trophic Level At the base of the food chain lies the primary producers. Primary producers are principally green plants and certain bacteria. They convert solar energy into organic energy. Above the primary producers are the consumers who ingest live plants or the prey of others. Some consumers called detritivores consume detritus which is dead organic matter. Examples are clams, crabs, termites, and beetles. Decomposers, such as, bacteria, molds, and fungi make use of energy stored in already dead plant and animal tissues.

Keystone species- some species are clearly critical to the functioning of an ecosystem. Example: Sea otter What are keystone species? The main predator of the urchins is the sea otter, Enhydra lutris. Sea otters are large marine mammals that live in a broad range from Alaska to Northern California. They feed mainly on invertebrates and urchins are a major portion of their diet. Because of their feeding habits, sea otters act as a keystone species in the kelp forest. Keystone species are features of an ecosystem that are essential in maintaining its balance.

Three Levels of Biodiversity Genetic diversity is: A building block of life Responsible for the variability among individuals within any species, based on variations in genes. Associated with adaptations to local conditions. Genetic variation is the cornerstone of all biodiversity.

Three Levels of Biodiversity Ecosystem diversity- refers to the variety of habitats, communities, and ecological processes within and between ecosystems. Examples: savannas, rain forests, oceans, marshes, deserts, and all the other environments where species evolve and live.

Three Levels of Biodiversity Species diversity is all of the different kinds of living things found in a certain habitat or ecosystem. Biodiversity crisis focuses on species diversity. As more species are lost to extinction, species diversity declines.

1. Habitat loss, degradation, and fragmentation Habitat loss, degradation, and fragmentation are important causes of known extinctions. As deforestation proceeds in tropical forests, this promises to become the main cause of mass extinctions caused by human activity. Habitat loss has been brought by agriculture, urbanization, deforestation, mining and pollution.

2. Over-hunting The human harvesting of wild organisms at rates exceeding the ability of populations of those species to recover has been a significant cause of the extinction of hundreds of species and the endangerment of many more, such as whales and many African large mammals. Most extinctions over the past several hundred years are mainly due to over-harvesting for food, fashion, and profit. Commercial hunting, both legal and illegal (poaching), is the principal threat.

3. Invasion of non-native species Some introduced species disrupt their community by simply eating the native organisms or outcompeting them for food. For example, 12 species of birds and 6 species of lizards have become extinct since the arrival of the brown tree snake (Boiga irregularis) in the island of Guam.

 Exotic species invasion, which is behind habitat fragmentation, has become the second largest threatening factor to the maintenance of the global-scale level of biological diversity.  Estimated 50,000 nonindigenous species established in the United States  Environmental damage and economic losses that total over an estimated U.S.$125 billion per year

What makes a successful invader?  Highly competitive, highly adaptive and highly successful at reproducing  The lack of natural predators  Successful colonists tend to be relatively abundant  Many invasive plant species reproduce asexually by apomixis or vegetative reproduction  Invasive genotypes were larger than native genotypes and produced more seeds  Absence of enemies (e.g., herbivores in the case of plants) leaves nonindigenous species more resources available for growth and reproduction and thereby allows them to out-compete native species  Established species often persist at low and sometimes undetectable numbers and then “explode” to become invasive years or decades later

Consequences of Rising Human Population To summed up all the threats and problems presented in this Lesson, it all comes down to there’s too many human beings. At present, even were human populations to decline substantially or use of land become far more efficient, the current global extent, duration, type and intensity of human transformation of ecosystems have already irreversibly altered the terrestrial biosphere.