Chapter 3 (pgs 34-49)

Change in the Biosphere

The Changing Environment

Humans have only lived on earth for <0.5 million yearsHow old is earth?How did earth form?

Earth has been changing since it formedDo you know some ways that

earth is changing?Most natural changes are so

slow that you don’t see them in a lifetimeSome rapid changes have taken

place from human activities

Changes in the Lithosphere***Remember – the

lithosphere is the layer of land on earth***

The lithosphere is made of several large moveable tectonic plates

Molten (liquid) rock from inside earth oozes out through the cracks between the plates

The molten rock hardens (as it cools) pushing apart the plates – this may cause earthquakes

Mountain chains form when the plates cause the Earth’s surface to buckle

Earthquakes:Vibrations caused by the Earth’s crust “slipping”

along a fault line (break in the Earth’s crust)Richter Scale – scale used to measure

earthquake intensityRanges from 1 – 10

(9.5 is most powerful to ever be recorded)Most earthquakes take place on or near fault

linesThe biggest faults are near the boundaries

where tectonic plates meet This is why California has more earthquakes

than NJ

Volcanoes:A mountain built from

magma (melted rock) that rises from the Earth’s interior to its surface.

Often located near tectonic plate boundaries.

On land or under sea.“Ring of Fire” contains

75% of world’s active volcanoes that are on land.

Other Lithospheric Changes

Weathering – the breaking down of rock by heat, water, ice, wind, and pressure – no movement

Erosion – the broken down rock is then carried off by water, wind, ice, and gravity - movement

Changes in the Hydrosphere***Remember – the

hydrosphere includes all parts of earth made up of water***

As the continents have changed, so have the bodies of water

Most water changes occur slowly and steadily over time

Other water changes occur in a series of cycles:Ice ages – millions of yearsEl Nino – every 4-7 years

Ice Ages• Long periods of cooling, when

glaciers move from poles and cover much of Earth

• Glaciers - huge masses of ice form called

• After the ice age, the glaciers retreat back to the poles

• Evidence of five ice ages in the Earth’s history (most recent ended 12,000 to 10,000 years ago

• When glaciers move, they scrape across earth moving rocks and water to new places

El Nino

• Every December, a warm, nutrient-poor water current flows southward along the coast of South America

• Normally this warm current is quickly replaced by a cold, nutrient rich current during an upwelling

• Every 4-7 years, the upwelling doesn’t occur

• The nutrient poor water cannot support fish life

Changes in the Atmosphere

Early Earth’s atmosphere was mostly water vapor, carbon dioxide & sulfur from volcanic eruptions.

Bacteria evolved that could perform photosynthesis and released first oxygen into atmosphere.

For the past 3.5 billion years, the atmosphere consists of recycled nitrogen, oxygen, carbon dioxide & water vapor

Changes in the Atmosphere

Much of earth’s carbon is cycled through the carbon cycle

Some is stored in the bodies of organisms – dead or alive

Fossil fuels (coal, natural gas) – formed by breakdown of dead organisms

When we burn fossil fuels, we release carbon dioxide

Greenhouse Effect-release of stored carbon into atmosphere by burning organic matter, which influences the temperature of the Earth.

Check for Understanding:1. Through what process does weather

affect the shape of land?2. In what ways does El Nino affect the

economy?

Needs of Organisms

An environment should provide an organism with everything it needs to live

Every organism has a different set of needs and has evolved to fit its environment

All organisms have certain needs in common:WaterSource of energyLiving spaceSuitable climate

WaterFresh water is one of the

most important abiotic factors in support of life

Plants need water to growAnimal populations need

plants and waterOcean organisms are

affected by water qualityWarm water contains less

dissolved oxygen than cold water – can’t keep organisms alive

Food and EnergyAll energy used by

organisms comes from the sun and is stored as food

Plants capture energy from sun and make food through photosynthesis

Animals eat plants and get energy

Food contains energy, minerals, and vitaminsNutrients-all the

substances that an organism requires from food.

Living Space

All organisms need space to live and obtain materialsPlants need space between

them to get sunlight and water

Animals need space to get food, water, mates

Territory – area claimed as a living space by an individual animal (mark their territory)

Size of territory – determined by animal

They will compete till DEATH!

Climate• Climate – the temperature

and weather that an organism is adapted to live in – it produces varied responses in organisms

Range of tolerance – acceptable range of temperature for an organism’s survival

Most organisms’ body temperatures are determined by the environment (cold blooded)

Many organisms become dormant to survive cold temperatures

ClimateDormant – all metabolic life

processes slow down in an organism [ex: plants in winter bacteria in refrigerator]

Other organisms (warm blooded) use energy to maintain a high body temperature

Warm blooded animals need 10 X as much food!

Some animals also become dormant (hamsters, worms)

Hibernation – heart rate and breathing slow, body temperature drops, enters a sleep-like state

Hedgehogs: Usually, hedgehogs maintain a constant body temperature, i.e 35 degree centigrade, during summer but at the onset of winter, their temperature drops to 6 degree centigrade in order to cope with the scarcity of food. Hedgehogs go into hibernation for about 2 to 5 months with the males hibernating before the females.

Badgers: They are torpors or temporary hibernators and in winters they store enough food in their burrows, so that they may wake up, eat and go back to sleep again. Badgers are omnivores, that is they eat both plants and animals. Honey badgers, one of the types of badgers are nocturnal animals.

Frogs and Toads: Frogs living in colder climates, hibernate in winter in small creeks, cracks in logs and in rocky places. They store glucose in their bodies that keeps them from getting frozen. Some of the species of frogs even hibernate under water. Toads are cold blooded and nocturnal creatures. Their hibernation period begins from October and some toads are known to hibernate for as long as three to four years. They survive on body fat that has been stored in their bodies during the warm months.

Moths: Moths are a species of insects that closely resemble a butterfly. Moths hibernate in clusters and during the winters they sleep in creeks or cracks in the wood.

Check for Understanding:1. In what ways does the behavior among

territorial animals differ?2. How does hibernation help animals to

survive?3. Do you think that the amount of water used

by each person in the United States has changed over time? If so, in what way? Explain your answer.

4. Suppose a particular area was to experience a sudden change in rainfall and temperature that lasts a long time. Do you think the area would lose its ability to support life?

The Mississippi FloodRead page 41 in your textbook“The Mississippi Flood – Who should pay for

property damage on a floodplain?”Answer the decision questions fully and

hand in.

The Ecosystem

Ecosystem is a highly organized, structured environment that is delicately balanced

Ecosystems can be studied on many levels, from individual species to the interactions within the entire ecosystem.

Includes all the biotic and abiotic factors in an area.

SpeciesA group of

organisms similar to one another, able to breed and produce fertile offspring

All members have similar needsRange of toleranceSize of territoryType of food

Members often compete with each other for resources

HabitatThe type of environment in

which a particular species livesDescribe the habitat of a

birdDescribe the habitat of a

fishDescribe the habitat of a

pandaProvides appropriate food,

shelter, temperature, etc that a species needs for survival

Destruction of habitat is a serious threat to the survival of many species

Geographical RangeThe total area in which a

species can live Depends on the size of the

area where the habitat is suitable

Mountain LionRequires habitat with diverse

plants, large hunting territory, variety of prey animals

Used to roam all of continental U.S.

Humans took over their range

Now restricted to western mountains

Populations and CommunitiesPopulation - all the

members of a species that live in the same area

For example:Ants in an ant hillDandelions in a field

Community - all the populations that live and interact in the same environment

Foe example:The ants and the

dandelions

Ecosystem

Includes all the communities that live in area as well as the abiotic factors in that environment

Include water, soil, climate

Healthy ecosystem contains a wide variety of organisms

BiodiversityThe variety of species

in an environmentIf enough of a habitat

is destroyed, the species that live there can become extinct

This decreases biodiversity and stability

For example – tropical rainforests

Check for Understanding:

1. What factors are included in an ecosystem?

2. What do you think is the geographical range for human beings?

3. Some ancient cultures, such as the societies that live in rain forests, are shrinking as a result of the destruction of their habitat. Do you think human societies should be protected, as are endangered species of plants and animals? Explain.