Understanding the Biodiversity Crisis

The Biodiversity Crisis

• Species extinctions happen at a rate of 500–1000 times the normal rate.
• High extinction rates may cause a significant decrease in the biodiversity of the planet within the next 100-200 years.
• Biodiversity loss includes the extinction of known and yet to be discovered species.
• Most undiscovered species that are facing extinction live in tropical rainforests, like in the Amazon basin.
• Rainforests are diverse ecosystems that are being destroyed by deforestation.
• About 20% of the Amazon rainforest was lost between 1970 and 2011.
• Lowland rainforests in locations such as Madagascar are high biodiversity habitats, but they are still vulnerable.
• 10% of the original coastal lowland forest in Madagascar remains, with research indicating that half of the original biodiversity is already lost.
• Biodiversity is biological variety that is measured at different organizational levels.
• Ecologists measure biodiversity by looking at the number of species alongside the number of individuals within each species.
• Relative abundance is the number of individuals within each species.
• Genetic diversity is a measure of biodiversity used in conservation efforts.
• Biodiversity loss is the reduction of biodiversity because of species displacement or extinction.
• The loss of a particular species may seem unimportant, but the accelerated extinction rate indicates the loss of thousands of species.
• The loss of species can have dramatic effects on human welfare by collapsing ecosystems.
• Agriculture started after hunter-gatherer societies started settling in one place, modifying their immediate environment.
• Humans rely on ecosystems for resources such as food, medicine, clean air and water, recreation, and inspiration.

Types of Biodiversity

• Biodiversity commonly refers to the number of species in a location, such as the 2078 species of birds in North and Central America.
• Sophisticated measures of diversity consider the relative abundance of species.
• Forests are more diverse with equally common species rather than having one dominant species.
• Genetic diversity is the variety of genes within a population and raw material for species adaptation.
• A species' ability to adapt to changing environments depends on its genetic diversity.
• Ecosystem diversity refers to the number of different ecosystems on Earth or in a specific area.
• The loss of an ecosystem results in the loss of species interactions and biological productivity.
• The prairie ecosystem in North America is an example of a largely extinct ecosystem that has been replaced by crop fields, pasture lands, and suburban sprawl.
• The loss of soil productivity occurs from the loss of interactions in the original ecosystem.

Current Species Diversity

• Knowledge of the species that inhabit the planet is limited, with only 13% of eukaryotic species named.
• Various initiatives are aimed at cataloging described species, with the internet facilitating that effort.
• With 17,000–20,000 new species described each year, it would take around 500 years to describe all existing species.
• Extinction is outpacing species description.
• Describing species involves biologists identifying an organism's characteristics to determine if it belongs to any other described species.
• Describing species allows biologists to find, recognize, and study species, leading to discoveries valuable to humans and ecosystems.

Patterns of Biodiversity

• Biodiversity is not evenly distributed across the planet.
• Lake Victoria once contained nearly 500 species of cichlids before an exotic species caused a mass extinction.
• Endemic species live in only one location, such as the Barton Springs salamander only being in one spring in Austin, Texas.
• Endemic species with restricted distributions are vulnerable to extinction.
• Lake Huron has 79 fish species, which are also in other North American lakes.
• Species diversity in Lake Victoria and Lake Huron varies due to latitude and age.
• Lake Victoria is a tropical lake that is 15,000 years old, whereas Lake Huron is a temperate lake that is 7,000 years old.
• Biogeography studies the distribution of the world's species in the past and present, understanding the physical environment and how changes affect species.
• Ecological biogeography studies the current factors that affect the distribution of plants and animals.
• Historical biogeography studies the past distribution of species
• Conservation biogeography focuses on protecting and restoring species based on historical and current ecological information.
• Biodiversity increases as latitude declines, meaning there is more biodiversity closer to the equator.
• Some hypotheses for this are the age of tropical ecosystems and greater energy input from the sun.
• Ecosystems in the tropics may promote speciation by increasing habitat complexity and providing more ecological niches.
• The perception is that the stability of tropical ecosystems promote speciation.

Importance of Biodiversity

• Loss of biodiversity can have consequences on ecosystems because of the complex interrelations among species such as the extinction of one species causing the extinction of another.
• Biodiversity impacts human health and our ability to feed through harvesting wild animals and agriculture.

Human Health

• Medications come from natural chemicals made by a variety of organisms.
• Some plants produce compounds that protect themselves from insects and other animals, and these compounds can also work as human medicines.
• Older knowledge about plants and their uses was compiled in herbals.
• The great apes, orangutans, chimpanzees, bonobos, and gorillas self-medicate with plants.
• Medicines derived from plant compounds include aspirin, codeine, digoxin, atropine, and vincristine.
• Many medicines were once plant extracts but are now synthesized.
• Antibiotics are largely derived from fungi and bacteria.
• Animal venoms and poisons are being researched for their medicinal potential.
• In 2007, the FDA approved five drugs based on animal toxins to treat diseases such as hypertension, chronic pain, and diabetes.
• Human evolutionary history has adapted us to a natural environment.
• Built environments can create stresses that affect human health and well-being.

Agricultural

• Human groups have been breeding and selecting crop varieties for over 10,000 years.
• Crop diversity has matched the cultural diversity of human populations.
• Potatoes were domesticated around 7,000 years ago in the central Andes of Peru and Bolivia, with varieties bred to thrive at specific elevations and conditions.
• Every plant, animal, and fungus cultivated by humans has been bred from wild ancestor species into diverse varieties.
• The risks of low crop diversity is shown with the Irish potato famine (1845–1852 AD), where the potato crop was wiped out from blight.
• Maintaining crop biodiversity ensures disease resistance.
• Seed companies must keep breeding new varieties to keep up with evolving pest organisms.
• Seed companies are participating in the decline of varieties as they focus on selling fewer varieties in more areas.
• Creating new crop varieties relies on the diversity of varieties available alongside the availability of wild forms related to the crop plant.
• Government agriculture departments have maintained seed banks of crop varieties since the 1920s.
• In 2008, the Svalbard Global Seed Vault in Norway storing seeds from around the world began as a backup system to regional seed banks.
• The Svalbard seed vault is carved deep into the island's rock with conditions such as temperature and humidity maintained for seed survival.
• Crops are dependent on the biodiversity of the ecosystems in which they are grown.
• Biodiversity creates conditions under which crops can grow through ecosystem services.
• Ecosystem services include nutrient cycles, soil texture maintenance, plant pollination, and crop pest control.
• Honeybee pollination contributes billions of dollars each year.
• Honeybee populations in North America have suffered large losses from colony collapse disorder.
• Humans compete for their food with crop pests that are insects.
• The use of pesticides to control these competitors are costly and ineffective.
• There has been a significant impact by predators and parasites in removing pests from fields.

Wild Food Sources

• Humans obtain food resources from wild populations, primarily wild fish populations.
• Aquatic resources provide the main source of animal protein for about one billion people.
• Production from global fisheries has been declining since 1990.
• Few fisheries are managed sustainably.
• Fishery extinctions lead to a restructuring of the marine ecosystem in species that have been over-harvested.
• The collapse of fisheries affects human populations and creates a loss of inexpensive protein sources.