What is Species Diversity? - Definition, Importance & Examples
Definition of Species Diversity
Imagine chasing a horned lizard, and it uses a bizarre tactic to deter you, squirting blood at you out of its eye. Imagine scuba diving and encountering one of the ugliest fish in the world, called the anglerfish. This is not science fiction; this is real. There are some bizarre creatures that call Earth home. The diversity of creatures roaming Earth is absolutely astounding.
Species diversity is defined as the number of species and abundance of each species that live in a particular location. The number of species that live in a certain location is called species richness. If you were to measure the species richness of a forest, you might find 20 bird species, 50 plant species, and 10 mammal species. Abundance is the number of individuals of each species. For example, there might be 100 mountain beavers that live in a forest. You can talk about species diversity on a small scale, like a forest, or on a large scale, like the total diversity of species living on Earth.
Species Diversity of Earth
How many species do you think live on Earth? There are approximately 1.8 million different species classified on Earth. Of all the species identified, nearly one million are insects! New species are being discovered each year. Scientists estimate that there may be between 5 to 30 million species that actually live on Earth. Each year, approximately 13,000 more species are added to this growing list of known species. For example, in 2013, a species of a venomous snake called the green palm-pit viper was discovered in the country of Honduras.
In 2014, a carnivorous mammal species called olinguito was discovered in Colombia and Ecuador. Who knows what weird creature might be discovered this year!
The hottest spots for species diversity are tropical rainforests. Tropical rainforests comprise only 7% of all land on Earth yet are home to nearly 50% of all the species on Earth! In Costa Rica, there are over 1,400 species of orchids, 1,200 species of butterflies, and 600 species of birds! Interesting species of mammals live here as well, like howler monkeys, jaguars, and sloths.
Importance of Species Diversity
There are numerous reasons why species diversity is essential. Each species has a role in the ecosystem. For example, bees are primary pollinators. Imagine what would happen if bees went extinct. Fruits and vegetables could be next, and subsequently the animals that feed off them - this chain links all the way to humans. Various species provide us not only with food but also contribute to clean water, breathable air, fertile soils, climate stability, pollution absorption, building materials for our homes, prevention of disease outbreaks, medicinal resources, and more. Let's look at some examples.
Species diversity contributes to ecosystem health. Each species is like a thread holding together an ecosystem. If a species disappears, an entire ecosystem can start to unravel. Species diversity is crucial for ecosystem health. For example, in the Pacific Northwest, salmon holds together the entire ecosystem. Salmon carry rich nutrients from the ocean back to the stream environment. When salmon die, those nutrients are gobbled up by insects, plants, mammals, and birds. If salmon were to disappear, the impacts would be felt through the entire food chain.
Species diversity also contributes to medicine. Scientists have discovered that over 3,000 plants have cancer-fighting properties. For example, a plant called rosy periwinkle has natural chemicals that help treat childhood leukemia. Also, the fruit of a tree called the Chinese star anise is an ingredient in flu vaccines. The list goes on: aspirin, codeine, and pseudoephedrine all are sourced from plants. There are medicinal treasures still yet to be discovered. Perhaps hidden in some forest is the cure to cancer.
Threats to Species Diversity
Our human population is skyrocketing with over seven billion people living on Earth. As our population grows, so does our demand on our environment. A rise in population means more forests are cleared for homes, more wetlands are drained for shopping centers, and more drinking water sucked from our rivers. This constant pressure on the environment is pushing many species towards the edge of extinction.
How many species are vanishing? This is the million-dollar question because no one knows exactly how many species actually exist on Earth. Estimates vary ranging from 200 to 23,000 species going extinct each year. Species like the golden toad in Costa Rica have recently vanished from the face of the Earth.
Loss of species diversity concerns scientists, bringing up important questions. What happens if we lose the majority of Earth's species? What does this loss mean for ecosystem health? What does loss of species diversity mean for human existence?
In this lesson, you learned that species diversity is defined as the number of species and abundance of each species that live in a particular location. The number of species that live in a particular location is called species richness. Abundance is defined as the number of individuals of each species.
There are approximately 1.8 million different species classified on Earth. New species are still being discovered each year. Scientists estimate there may be 5 to 30 million species that live on Earth. The hottest spots for species diversity are tropical rainforests.
Species diversity is important for ecosystem health and for medicine. If a species disappears, an entire ecosystem can start to unravel. The wood in our houses, medicines we take, and the food we eat is all connected to species diversity. Human population growth is threatening species diversity. As human population grows, so does the pressure we put on our environment. This constant pressure on the environment is pushing many species towards the edge of extinction. Estimates vary ranging from 200 to 23,000 species going extinct each year.
Species Diversity Overview
|Species diversity||the number of species and abundance of each species that live in a particular location|
|Species richness||the number of species that live in a certain location|
|Abundance||the number of individuals of each species|
Completing this lesson should help you with the following:
- Describe species diversity
- Identify diversity richness
- Recognize the importance of abundance in diversity
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