Biology Unit 8 Explanation & Notes

Section 15.1 – Life in the Earth System

The biosphere is the part of the Earth where life exists. The land, air, and water where organisms live are all in the biosphere. If all of the living things were collected in the biosphere, you would have the biota.

Four interconnected systems of the Earth – draw a symbol next to each bubble!

Biosphere – all of Earth’s life; other systems are included Hydrosphere – all of Earth’s water, ice and water vapor Geosphere – the continents, rocks, sea floor, and everything below Earth’s

surface Atmosphere – the air blanketing Earth’s solid and liquid surface

Is Earth alive?

The Gaia hypothesis considers Earth as somewhat living where its atmosphere, geosphere, and hydrosphere that interact to create a biosphere full of life. It does not suggest that the Earth is a thinking being that regulates its system.

Section 15.2 – Climate – 3 main zones

The climate is the long-term pattern of weather conditions in a region like average temperature, precipitation, and humidity. Within each climate, you can have a microclimate which is the climate of a small specific place in a large area (San Francisco fog or June gloom in SoCal).

There are three main climate zones: polar, temperate, and tropical. The zones are related to the amount of sunlight it gets. The direct impact of sunlight creates more heat where the curved regions have less intense sunlight and less heat.

ZONE LOCATIONS – POLAR:________________ TEMPERATE:________________ TROPICAL:_______________

Section 15.3 – Biomes - There are 6 major biomes in the world:Tropical, grassland, temperate, desert, taiga, & tundra.

BiomesName Tropical Grassland Temperate

Temperature Warm all year round Tropical: warm throughoutTemperate: dry & warm in

summer, cold in winter

Deciduous forest: hot summers, cold winters

Rain forest: mild summers, cooler winters

Precipitation Yearlong rainfall Tropical: definite dry and rainy seasons

Temperate: dry, snow in winter

Deciduous forest: spaced precipitation over the year

Rain forest: one long wet season, somewhat dry summer

biospherebiota

biosphere

hydrosphere

geosphereatmosphere

Biodiversity Thick forests, most animals live in upper branches of forest canopy

Tall grasses and scattered trees, hoofed animals (gazelle) and burrowing animals (prairie)

Deciduous forest: deciduous trees shed leaves during winter (maple)Rain forest: coniferous trees keep their needles all year (evergreen)

Name Desert Taiga Tundra

Temperature Hot days with cold nights long, cold winters with short, warm summers

Subzero temperatures through long winter

Precipitation Very dry; low rainfall Humid summers with cold winters and moderate rainfall

Little precipitation; permanently frozen ground

Biodiversity Plants store water with deep roots (cactus) and animals are nocturnal

Coniferous trees dominate, thick fur mammals

Mosses and tiny plants; low bio-diversity

Question: Which biome has the most biodiversity and which biome has the least? Which biome do you live in?

MOST: LEAST: “I live in”:

**partner up, complete pgs 3,4,6, and 9 in your Unit 8 SAW!

Section 15.4 – Marine Ecosystems – The four major ocean zones

Intertidal zone – strip of land between the high and low tide lines (beach life); life has to deal with constant changing conditions.

Neritic zone – stretches from intertidal zone to edge of continental shelf (up to 200 meters deep); contains most of the biomass in the ocean. Phytoplanktons are tiny free-floating organisms (algae) that carry out large part of photosynthesis on earth live in this zone.

Bathyal zone – extends from 200 meters to 2000 meters out towards the base of the continental shelf; burrowing animals live in the murky silt that collects.

Abyssal zone – area lower than 2000 meters (1.25 miles) deep is completely dark; animals are chemosynthetic or create light for attracting prey and mates.

**SKIP SECTION 15.5 (pg.19-21) in your unit 8 SAW

Section 16.1 – Human Population Growth and Natural Resources

Balance is Key! The human population is over 6 billion and scientists may disagree on how many people the Earth can support, they all agree that there is a limit on the carrying capacity. This chart shows an average projection at about 10 billion people. Technology has greatly increased the carrying capacity of Earth in the last century (farming, medicine, etc).

Limited versus unlimited

The United States currently uses oil and coal as the two main sources energy. These are nonrenewable resources because they are used faster than they form (million year process). Resources that are replenished over time or can never run out are renewable resources. Wind and solar energy are examples along with plants and animals if they are carefully managed.

Easter Island had lots of trees until human habitants (over 1000 years) cut down all of them for resources faster than they could grow. Now, Easter Island is a barren landscape.

An ecological footprint is the amount of land necessary to produce enough food, water,

shelter, and energy. The average U.S. person has an ecological footprint large enough to cover 24 football fields; we would need 5 Earths to sustain the world population if everyone was living as North Americans. What would you say to someone if they asked you comment on your large “footprint”?

**Partner up! Complete pages 27 and 28 in your unit 8 SAW

Section 16.2 – Air Quality

Los Angeles is one of more polluted cities in the U.S. Smog is a type of air pollution caused by sunlight interacting with air pollutants from the burning of fossil fuels. Particulates are small pieces of dust, metal, and fuel that are floating in the air and can cause health problems when breathed in. When it rains, you get acid rain which causes the pH level of water lowers below normal causing damage to water supplies and habitats.

The greenhouse effect is when carbon dioxide, water, and methane slow the release of heat from sunlight into the atmosphere; much like a car with windows rolled up in the sun. Without this effect, the Earth would be too cold for life. However, global warming which is the increase in global temperatures is agreed by most scientists as a result of increased levels of greenhouse gases in the atmosphere.

Section 16.3 – Water Quality – toxins “magnify” along the food chain

An indicator species or bioindicator, provides a sign of the quality of the ecosystem’s environmental conditions. Frogs are typically considered an indicator species due to their permeable skin which is sensitive to any chemical pollutants in the water to a point where deformities occur.

Video study: Let’s watch this clip about the decline in the frog population

http://www.youtube.com/watch?v=ZWHibAQ0Sso Do you care if the frog population disappears?

Biomagnification is when a pollutant moves up the food chain as predator easy prey, creating higher concentrations in the predator’s bodies. Another example of biomagnifications is the level of mercury in certain fish based on it predatory diet. Who likes sushi???

**Partner up! Complete pg. 31 and 33 in your unit 8 SAW!

Section 16.4 – Threats to Biodiversity – why should we care?

Biodiversity ensures the future of the Earth. Without biodiversity, the risk of the ecosystem not being able to handle change increases. Plus, many important medicines come from plants as well as technological advancements (adhesives found in mussels inspiring medical implants).

Habitat fragmentation occurs when a barrier forms that prevents an organism from getting to its home. Roads or deforestation are examples of obstacles that animals have to deal with to get to its habitat.

An introduced species is any organism that was brought to an ecosystem by human actions. They can pose a great threat to the stability of the ecosystem by preying or crowding out the native species. Here is an example of the Kudzu plant that was introduced in eastern U.S. over a 100 years ago is a problematic introduced species.

Section 16.5 – Conservation – protecting the future

Show of hands! – How many of you have thrown unwanted food on the ground instead of in the trash? What’s the reason for doing this? Why are these reasons not valid?

Conservation is key to ensuring a eco-healthy future and wasteful practices will make it difficult for future generations to live as comfortably as we do. Sustainable development is a practice in which natural resources are used and managed in a way that meets

current needs without hurting future generations. For example, instead of clear cutting entire sections of forests, selective cutting of trees allows faster regrowth of trees.

Species that are on the endangered species list can be umbrella species where its protection leads to the protection of other species. This is simply because its habitat will be protected which will protect any other species living there too.