1. BIOLOGY SUSTAINABLE ECOSYSTEMS & HUMAN ACTIVITY Life on Earth (P.28-29)

2. Life on Earth Of all the planets in the Solar System, Earth is the only one teeming with life. Millions of organisms exist in countless habitats on the land and in the water on our unique planet.

3. Diversity of Life on Earth A habitat is the place where an organism lives. Terrestrial habitats are found on land. Cacti and rattlesnakes live on land in arid (dry) deserts. Enormous trees with swarming insects live in tropical rainforests. Aquatic habitats are found in water. Colourful fish swim through the waters of the ocean’s coral reefs. Frogs and crayfish live in small freshwater ponds. But what features of Earth permit such a diversity of life to exist? HABITAT  place where an organism lives  terrestrial habitat - land (desert, rainforest, …)  aquatic habitat - water (coral reef, lake, …)

4. Earth’s Spheres – The Biosphere If you observed Earth from space, you would see that Earth is surrounded by a thin gaseous layer swirling with clouds – the biosphere. The biosphere is the part of the planet, including all the water, land, and air, where life exists. It is very thin relative to the whole Earth. If Earth were represented by a beach ball, the biosphere could be represented by a sheet of plastic wrap laid over it surface one layer thick.

5. Earth’s Spheres – The Biosphere The biosphere is the most important system on Earth because not only is it our home, but it is home to countless other organisms. Three main interacting components make up the physical environment of the biosphere. They are the atmosphere, lithosphere, and hydrosphere.

6. Earth’s Spheres – The Biosphere

7. BIOSPHERE all the places on Earth (air, land, and water) where life exists 3 main components:  Atmosphere  Lithosphere  hydrosphere

8. Earth’s Spheres – The Atmosphere Earth’s atmosphere is the thin layer of gases that surrounds the planet. It contains gases such as water vapour, oxygen, and carbon dioxide that are necessary for living things. The atmosphere acts like a blanket wrapped around Earth and prevents Earth from getting too warm or too cool. The atmosphere also blocks some of the Sun’s radiation, which can harm organisms, including humans. Without the atmosphere, life on Earth would not have been possible.

9. Earth’s Spheres – The Atmosphere ATMOSPHERE  thin layer of gases (H20, O2, CO2,...) that surround Earth and support life  prevents Earth from getting too warm/cold  blocks the Sun’s harmful radiation (some)

10. Earth’s Spheres – The Lithosphere & Hydrosphere The lithosphere is the rocky outer shell of Earth. It consists of the rocks and minerals that make up the mountains, ocean floors, and the rest of Earth’s solid landscape. LITHOSPHERE  rocky outer shell of Earth

11. Earth’s Spheres – The Lithosphere & Hydrosphere The hydrosphere consists of all the water on, above, and below Earth's surface. It includes oceans, lakes, ice, groundwater, and clouds. HYDROSPHERE  all of the Earth’s water in solid, liquid, and gas form  oceans = 97%

12. Earth’s Spheres NOTE! All living things need space, water, and nutrients to survive. However, the supply of these resources is limited. Ultimately, the availability of resources places a limit on the number of individuals of a species that can survive. All life on Earth is vying for access to these resources

13. Earth’s Spheres LIFE ON EARTH  all living things need space, water, and nutrients to survive  the availability of these resources  controls the number of organisms

14. Check Your Learning 1. Unlike the moon (and other planetary bodies), explain how Earth’s mass is related to its ability to have an atmosphere. the gravitational attraction between Earth and the atmosphere (due to Earth’s mass) is large enough that Earth is able to hang onto it

15. Check Your Learning 2. How does the atmosphere help provide the conditions necessary for life to exist on Earth? (3 reasons)  contains gases necessary for living things  acts like a blanket to prevent Earth from getting too warm/cold  blocks some of the Sun’s harmful radiation

16. Check Your Understanding 3. Describe an extreme terrestrial habitat in Canada. Explain how organisms are adapted to living there. answers will vary from desert to tundra environments

17. Of all the planets in the Solar System, Earth is the only one teeming with life. But is there life elsewhere in the solar system? we don’t know – a space probe nicknamed “Juice”, aimed at launching in 2022, will spend at least three years studying Jupiter’s moons for signs of life (i.e. several of Jupiter’s moons including Titan, Europa and Ganymede seem to have properties that would support life, albeit below their icy surface)

18. Check Your Learning TEXTBOOK P.29 Q.1