Do Now - Recap What is biodiversity? What are generalized species and specialized species? Give an example of each. If a habitat is destroyed, which type of species is more likely to survive? Explain why.

Chapter 23 Habitat Destruction Loss of Biodiversity

Earth is home to a tremendous diversity of species Ecosystem diversity- the variety of ecosystems within a given region. Species diversity- the variety of species in a given ecosystem. Genetic diversity- the variety of genes within a given species.

Extinction – the disappearance of a species from all or part of the species’ geographical range. Extinctions are a natural part of ecosystem function. All ecosystems change. Niches appear and disappear. Species that lack the adaptations for survival in a changing environment become extinct. Other species may evolve to fill new or empty niches left by extinct species.

Mass extinction – when many species die in a relatively short period of time Mass extinctions are typically followed by rapid evolution. The few organisms that survive evolve to fill vacant niches.

The Five Global Mass Extinctions

The Sixth Mass Extinction Scientists feel that we are in our sixth mass extinction, occurring in the last two decades. Estimates of extinction rates vary widely, from 2 % to 25% by 2020. In contrast to previous mass extinctions, scientists agree that this one is caused by humans.

What is extinction? What is mass extinction? How does mass extinction affect biodiversity of an ecosystem?