Biodiversity Lecture Notes - Biodiversity Lecture Notes...

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Biodiversity Lecture Notes What is Biodiversity? The term biodiversity refers to the __number______________ of ______different______________ ___species______________ in a _given_________________ ____area____________ . In order to study biodiversity, scientist need to catalog all the species that exist on Earth. The number of species known to scientists is about ___1.7____ million, most of which are insects. Most scientists agree that we have not studied all of Earth’s species, and that the actual number is more like 10 million. Many species that have not been studied live in _remote________________ wildernesses, ____deep______ in the _ocean__________________ , and even in cities. Levels of Biodiversity Biodiversity can be studied and described at three levels: 1. __Species_________________ diversity—the number of different species in an area. This kind of diversity has received the most attention is and is most often what is meant by biodiversity. 2. ____Ecosystem_________________ diversity—the variety of habitats, communities and ecological processes within and between ecosystems. 3. _____Genetic______________ diversity—all the different genes contained within all members of a population. A gene is a piece of DNA that codes for a specific trait that can be inherited by an organism’s offspring. Benefits of Biodiversity Biodiversity can affect the _stability__________________ of an ecosystem and the _______sustainability___________________ of populations. Species are connected to ecosystems (remember, all things are interdependent): A healthy biosphere has ___balance________________ cycles of _energy__________________ and ____nutrients_______________ . Remember—energy flows through ecosystems in the form of food chains (and food webs) Remember—matter (nutrients) cycle through ecosystems (i.e. nitrogen cycle, carbon cycle, phosphorus cycle) When one species disappears, a strand in a food web is removed. How many strands can be removed before the food web collapses? A Keystone Species
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A ______Keystone______________ species is a species that plays a critical role in the structure of an ecosystem. Their influence is critical to the functioning of the ecosystem. An example is the sea otter. Late 1800s sea otters were hunted for fur—they disappeared from Pacific Coast. Sea urchins, now with no predators ate all of the kelp. The kelp beds disappeared. 1937, a small group of sea otters were protected by scientific efforts. The population slowly grew. The otters preyed on their favorite food (urchins), the kelp beds regenerated.
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