This tutorial will cover the topic of biodiversity. We will discuss the benefits of biodiversity, explore what ecosystem services are, and learn about the potential sixth major extinction.
Our discussion breaks down as follows:
- What Is Biodiversity?
- Ecosystem Services
- Sixth Major Extinction
1. What Is Biodiversity?
Before we can begin to discuss biodiversity, we first need to define what an ecosystem is, which is the living and nonliving components that interact in a given area.
With the definition of ecosystem under our belts, now we can look at what biodiversity means, which is the number and relative abundance of a species in a given area. The concept of biodiversity can also be extended to include the entirety of global biodiversity, or the number and relative abundance of species worldwide.
Biodiversity is important because, on a large scale, it supports and increases stability across ecosystems. Each species plays a different role in an ecosystem and all are interdependent on each other for the healthy functioning of the whole. A loss of species diversity would weaken us — even the loss of a single species in an ecosystem could have unforeseen widespread consequences, including the loss of other species.
An example of such a scenario would be the extinction of coral reefs. Coral reefs worldwide are disappearing, due to global warming, faster than forests are from deforestation. If they were to go completely extinct, it would have widespread effects. Thousands of aquatic species make their homes in and around coral reef systems. Without them, those species will be threatened and entire ecosystems will be weakened, essentially creating a ripple effect of damages. The result will impact fisheries and reduce human economic and food sources.
- The living and nonliving components that interact in a given area.
- The number and relative abundance of a species in a given area.
2. Ecosystem Services
As mentioned, biodiversity is key to maintaining ecosystem health. Ecosystems themselves provide many benefits to humans, which are called ecosystem services. There are four main categories of ecosystem services, as follows:
- Provisioning services, such as food, fiber, fuels, fresh water, and medicines.
- Regulating services, such as climate regulation, water purification, and pollination.
- Cultural services, such as religious or spiritual value and use, recreation, educational use, and aesthetic value.
- Supporting services, such as nutrient cycling, soil formation, and production of energy from sunlight.
Different parts of ecosystems provide different types of services. An example of such a service would be what plant species provide through photosynthesis: oxygen. Without this service, the atmosphere's mixture of different gases would become imbalanced. Humans require a certain mix of oxygen in the air to breathe and perform respiration. Without plants, there wouldn't be enough. The free oxygen that plants produce also eventually gets changed into atmospheric ozone, which is necessary to protect humans from UV radiation. Plants also absorb carbon dioxide, which buffers against the greenhouse effect and global climate change.
3. Sixth Major Extinction
Many scientists are considering the current era of human population growth to be the sixth major extinction, or the Holocene extinction. This era includes the last 12,000 years to the present. In that time, it is estimated that somewhere between 500,000 to one million species of birds, mammals, reptiles, amphibians, plants, and insects have gone extinct from over-harvesting, habitat degradation, and pollution from human population growth and activities.
Current science estimates that 140,000 species per year are going extinct due to present human activities. By 2050, it is estimated that approximately 30% to 50% of human-era species will have gone extinct. These numbers become even more impressive when you consider that the recovery of biodiversity from previous mass extinctions took millions of years.
Today we learned about the benefits and importance of biodiversity to ecosystem health. We discussed various ecosystem services that humans use, and what scientists are calling the sixth major extinction, or the Holocene extinction, resulting from human activities. Don't forget our key terms for today: ecosystem, which is the living and nonliving components that interact in a given area, and biodiversity, defined as the number and relative abundance of species in a given area.