Earth’s Spheres

Is there life on this planet?

Life on Planet Earth What special features and conditions does Earth have that make life possible? Some people say that Earth itself is a living organism. Does that seem possible to you?

Earth’s 4 Spheres

The Atmosphere What is it? What is it made of? What does it hold in? A layer of gases surrounding the earth. What is it made of? Nitrogen, Oxygen, Carbon dioxide, Water vapour, other gases What does it hold in? Thermal energy What does it block out? Ultraviolet light After students complete the table above, ask them which features of the atmosphere help make life possible. Have volunteers supply answers. Point out that: • all living things need water, carbon dioxide, and oxygen • thermal energy held in keeps temperatures moderate for life • UV light blocked helps protect life

Lithosphere Earth’s Solid Outer Layer

All of Earth’s water, in solid, liquid, and gas form. Hydrosphere All of Earth’s water, in solid, liquid, and gas form.

Biosphere The zone around the earth where life can exists. Locations where life can exist within the atmosphere, lithosphere, and hydrosphere.

Ecology Ecology is the study of how organisms interact with one another and with their environment.

Ecosystems An area in which living organisms interact with other living components (biotic) and non-living components (abiotic) All the living organisms that share a region and interact with each other and their non-living environment.

Abiotic Factors The non-living components of an ecosystem.

Abiotic Factors Sunlight - provides energy for all living things.

Water - all life processes depend on water. Abiotic Factors Water - all life processes depend on water.

Abiotic Factors Soil - determines the types of plants that can live in a certain location.

Abiotic Factors Temperature - determines the organisms that can live there.

Oxygen - most living things require it to live. Abiotic Factors Oxygen - most living things require it to live.

Biotic Factors The living or once living parts of an ecosystem. Ex: plants and animals.

Biotic and Abiotic Influences on Ecosystems A limiting factor is anything that keeps the population of a species from getting too big Ex) availability of food, water, human influence

Abiotic Factors All species have a tolerance range that they can survive in (optimal range = best conditions) This tolerance range dictates where the species will be successful Eg) tolerance range of a grizzly bear vs a polar bear

Biotic Factors Interactions between individuals often influences population size Ex) competition between a maple tree and a birch tree for soil nutrients, light, etc

Cont’d Interactions can involve other dynamics such as: Competition = vie for same resource eg) Lions and Hyenas both eat antelope Predation = one organism feeds one another eg) Lion eats an antelope Mutalism = both organisms benefit eg) bee and flower Parasitism = one lives on or feeds on another host Eg) tape worm and human Commensalism = one benefits, other neither benefits or is harmed eg) bird living in a tree