Species & Extinction

Extinction EXTINCTION occurs when the environment changes and the adaptations of a species are no longer sufficient for its survival. Most of the species that have lived on Earth no longer exist. Fossils provide evidence of how environmental conditions and life have changed.

Clues from fossils Let’s read from the NEW text on page 343 under the heading Clues from Fossils We have already discussed the different types of fossils in previous material. What can we learn by studying these fossils? What can we learn by studying these fossils? They can teach us about the climate, the plant life, the types of animals that lived in the area.

Fossils and Time By studying the age of fossils we can learn how the climate and the animals changed over time. There are different ways to find the age of fossils. Relative Dating – which is determining the approximate age of a fossil by it’s location in the soil layers. Absolute Dating – sometimes referred to as Radioactive Dating – scientist use radioactive elements that give off a steady amount of radiation as it changes to a non-radioactive element. Each radioactive element gives off radiation at different rates. By comparing the amount of radioactive element in the fossil to the non-radioactive element in the fossil they can get a really good idea of how old it is. (this does not always produce exact results, because the original amount of the radioactive element can never be determined for certain)

Fossils & ecosystems By studying fossils scientists can determine the type of ecosystem an animal or plant would have lived in. Also, by studying the fossils, we can learn how the ecosystem changed and how the organisms living in it adapted.

Ecosystems An ECOSYSTEM is ALL of the communities in a given area and the abiotic factors that affect them. All of the organisms, from the smallest bacteria to the blue whale, interact with their environment. Ecology is the study of the interactions among the organisms and their environment. Ecologists organize the environmental factors that influence organisms into two groups: Abiotic Biotic

Abiotic Factors ABIOTIC factors are the non-living parts of the environment. In any environment, birds, insects, and other living things, including humans, depend on one another for food and shelter. They also depend on the abiotic factors that surround them, such as water, sunlight, temperature, air, and soil. All of these factors and others are important in determining which organisms are able to live in a particular environment.

Let’s watch a video! http://player.discoveryeducation.com/index.cfm?guidAssetId=2C732E32-E564-4F96-A45C-3BF6D0BAFB1E&blnFromSearch=1&productcode=US Before we begin the video we are going to take a Pre-test to see what you know now. After the video we take a post-test to see how much you learned. SO PAY ATTENTION!!! Print off the video pre-test & post-test

Biotic Factors BIOTIC factors are all of the living or once-living organisms in the environment. Abiotic factors do not provide everything an organism needs for survival. Organisms depend on other organisms for food, shelter, protection, and reproduction. How organisms interact with one another and with abiotic factors can be described in an organized way.

Levels of organization The living world is highly organized. Atoms are arranged into molecules, which in turn might be organized into cells. Cells form tissues, tissues form organs, organs form organ systems. Together, organ systems form organisms. Biotic and Abiotic factors also can be arranged into levels of biological organization.

Biological Organization ORGANISM – one individual from a population. POPULATION – All of the individuals of ONE species that live in the same area at the same time make up a population. COMMUNITY – the populations of different species that interact in some way. ECOSYSTEM – ALL of the communities in an area and the abiotic factors they interact with. BIOME - A large region with plants and animals well adapted to the soil and climate of the region. BIOSPHERE - The level of biological organization that is made up of ALL the ecosystems on Earth.

Characteristics of Populations You, the person sitting next to you, everyone in the class, and every other organism on Earth is a member of a specific population. Each organism must change as their environment changes. They must adapt. An ADAPTATION is an inherited trait that helps an organism survive. Adaptations include body structures that help an organism feed, move around, and protect itself.

Let’s watch a video about adaptations! http://player.discoveryeducation.com/index.cfm?guidAssetId=B6AE9A6D-851A-4899-A413-EED11BC86815&blnFromSearch=1&productcode=US We will first take a pre-test to see what you know!! Print teacher worksheets for ADAPTATIONS video.

Symbiosis SYMBIOSIS is any close interaction between two or more different species. Symbiotic relationships can be identified by the type of interaction between organisms. Mutualism is a symbiotic relationship in which two different species of organisms cooperate and both benefit. For example – the Yucca plant depends on moths to pollinate its flowers and the moth depends on the Yucca for a safe and protected place to lay its eggs and food for the larvae.

Commensalism is a form of symbiosis that benefits on organism without affecting the other organism. For example – a species of flatworm benefits by living in the gills of horseshoe crabs, eating scraps of the horseshoe crab’s meals. The horseshoe crab is unaffected by the flatworms.

PARASITISM is a symbiotic relationship between two species in which one species benefits and the other species is harmed. Some species of mistletoe are parasites because their roots grow into the tree’s tissue and take nutrients from the tree. But what does all of this mean to you?

Bringing it all together!! We discussed that extinction occurs when the environment changes and the adaptations of a species are no longer sufficient for its survival. Well, changes may include increased competition with other species, newly introduced predators, loss of habitat, and catastrophes. Based on the fossil record, scientists think most of the species that once lived on Earth are now extinct – It is an approximate of 99% of the Earth’s species are now extinct!!

When a species becomes extinct it affects everything!! You may not think so, but even the climate becomes affected when species become extinct. We will cover more of this in our next unit – ENERGY & ECOSYSTEMS But first let’s look at the Human impact on Extinction.

The Human impact on Extinction http://player.discoveryeducation.com/index.cfm?guidAssetId=661d153e-0114-41cb-a676-5257298ec162&productcode=US&CFID=201842&CFTOKEN=25126340