Ecosystems

Introduction to Physical Geography

HideShow resource information

Biotic= living

Abiotic= non living

Changes to an ecosystem

Sudden

  • natural disaster
  • manmade
  • preditor
  • disease

Gradual

  • global warming
  • ice caps melting
1 of 17

Distribution of ecosystems

3 main factors that affect where ecosystems develop:

1) light

2) moisture

3) heat

Food Chain example

plant--------->insect-------------------> Bird------> hawk

Question: What is HDI?

2 of 17

Answer: Human development Index

a measurement of life expectancy, literacy, eduacation and standard of living.

3 of 17

Millennium Development Goals

  • reduce poverty
  • educate every child
  • equal chances for girls
  • reduce nimber of children dieing
  • ensure a healthy motherhood
  • fight infectious disease
  • clean up the enviroment
  • share responsibility for making the worls a bette place

Qustion: what is 3rd world debt

4 of 17

countries which have loaned money form a MEDC but now cannot afford to pay it off and therefore its residents are suffering as the country can't spend money on its resients.

Benefits from living in a tectonic area:

  • Fertile soil
  • Nice scenery
  • Part of religion and culture
  • Tourist attraction
  • Precious metals and gems

Question: what are some problems?

5 of 17

  • Dangerous place to live
  • could damage ecosystems
  • Industry destroyed
  • Crops and livestock killed
6 of 17

There are three main parts: Core, Mantle and Crust.

Core: Central part of the earth. Temperature and pressure is enormous. Inner Core solid. Outer Core semi-liquid.

Mantle: made up of rocks. occupying over 80% of earth's volume. mainly solid, but upper mantel is a layer of semi-liquid molten rock (MAGMA). The magma is moved slowly underneath the crust by convection currents.

Crust: outer layer of rock. Floats on mantle. Solid rock. Broken into several pieces+ smaller pieces; AKA plates. fit together like a jigsaw. Some move around 2cm a year. The theory that describes this is Plate Tectonics. The place where 2 plates meets is a Plate Boundary (where most earthquakes/ volcanoes occur).

There is 2 types of crust: Continental (older/lighter/cannot sink/permanent) and Oceanic (younger/heavier/can sink/constantly being destroyed and replaced).

7 of 17

There are 3 types of plate boundaries: Convergent, Divergent, Transform.

Convergent (destructive): One plate collides with another. When Oceanic crust collides withContinental crust, the oceanic crust is forced downwards into the mantel and destroyed; a subduction zone (found where the pacific plate meets the Eurasian plate). Where to plates made ofContinental crust collide they are pushed upwards forming fold mountains(Himalayas/Andes).

Divergent (constructive): plates are forced apart by movement of magma in the mantle- new crust is formed in between (Mid-Atlantic volcanic ridge).

Transform (conservative): where two plates move horizontally past each other (San Andreas Fault).

8 of 17

 When two plates collide or slide past each other you get an earthquake. This means they occur at convergingand transform plates.

1. two plates move towards each other

2. one gets pushed under the other. If the plate gets stuck it causes strain in the surrounding rock. Sideways moving rocks can also get stuck.

3. when tension is released it produces strong shock waves; aka seismic waves.

4. Theshock wavesspread out form the focus (like a ripple effect). The waves get weaker as they move away from the focus.

Epicentre- point on the Earth's surfacedirectly above the focus.

Focus- The point where the earthquake starts.

A diagram on the following page shows the focus, epicentre, and seismic waves.

9 of 17

(http://www.mona.uwi.edu/earthquake/images/eqepifoc.gif)

10 of 17

Size or Magnitude of an earthquake is measured using a seisometre. Earthquake vibrations are measured by a sensetive arm which moves up and down on a seismograph (like a heart monitor).

Readings from the seismographare measured using the Richter Scale; a logarithic scale (earthquake measuring 5 is 10 tmes more powerful than one measuring 4 and 100 times more powerful than one measuring 3). This dertermins the strength of an earthquake.

Most serious earthquakes range between 5 and 10

11 of 17

Earthquake proof buildings are being introduced in MEDC cities; i.e. San Francisco. The buildings sway resulting in damages to the buildings being reduced, leading to a decrease in the number of people being injured or killed.

Improve preparation- in many places prone to earthquakes people try to prepare themselves. In Japan, 1st September is disaster day, the anniversary of the Tokyo earthquake of 1923; 156,000 were killed. The day is a public holiday which earthquake drills are practised. Theylearn how to protect themselves during an earthquake, how to fight fires and how to give first aid. The media is also used in countries like the USA, to give guidance about what should be done during an earthquake and the internet also provides guidance.

Emergency supplies- people should keep updating their emergency supplies to ready themselves for any shortages during a disaster.

12 of 17

KOBE

Location: Kobe, Japan Date: 17th January 1995

Cause: lies above a destructive plate margin. The Philippines plate was forced down under the Eurasian plate.

Epicentre: Kobe = VERY DESTRUCTIVE Magnitude: 7.2 on the Richter Scale

Damage: Primary- 200,000 buildings collapsed, bridges collapsed, 120 of 150 quays in the port of Kobe destroyed, trains derailed. Secondary- Electricity, gas, and water supplies destroyed, fires raged for several days- destroying 7,500 homes, 230,000 people made homeless, shortage of blankets, clean water and food, 716 aftershocks recored, industry forced to close (including Mitsubishi).

After: water, gas, telephone services fully operational by July. Fire areas cleared.Commercial buildings repaired. rail services back to normal. Port of Kobe 80% functional within a year. Replacement buildings had stronger earthquake resistance. Highrise buildings fitted with flexible steel frames. houses built with fire resistant materials. Increase in seismic instruments to record earth movements fitted.

13 of 17

Location: Mount. Saint. Helens, USA Date: 18th May 198

Cause of eruption: on a convergent plate boundary. The Jaun de Fuca Ridge collided with the North American Plate; being oceanic crust, the Jaun de Fuca Ridge was forced downwards into the mantle. The increased temperature turned the crust into magma which increased the pressure in the mantle andcaused themagma torise to the Earth's surface; resulting in the eruption on 1980.

Trigger: An earthquake on the 20th March 1980 measuring 4.2 on the Richter Scale.

Effects: 61 people killed, more than 200 houses and cabins destroyed, 185 miles of highway destroyed, 15 miles of railway destroyed, 27 bridges destroyed, estimated 7,000 big game animals (deer, elk and bear)perished, Birds and small mammals effected, somecrops destroyed, poor visibility > roads closed and flights cancelled, $1.1 billion damages,poor communications for a while.

14 of 17

Sichuan Earthquake Effects

Date: 17 May 2009

Magnitude: 7.9

Tectonic cause: Indian Plate colliding with Eurasian Plate

Primary Effects:

  • Water/Power supplies cut out
  • Building Collapse
  • Landslides

Secondary Effects:

  • Death (69.000)
  • Missing(18,000)
  • Ammonia spill from chemical plant
  • Water supply contamnated  
15 of 17

Sichuan Earthquake Responces

Short Term effects

  • 20 helicopters
  • Troops parachuting to asses damage                                        

Long Term effects 

  • Donations
  • Camps set up
  • Running Water
  • Medicine
  • Blankets
  • 1 million temporary homes 
16 of 17

Mercalli and Richter Scale

Pros of Mecalli Scale:

  • Shows Damage
  • Helps emergency service know what they are dealing with  

Cons:

  • Doesn't say how strong the earthquake was

Pros of Richter Scale:

  • Shows how strong the earthquake was
  • Impossible to find an earthquake to quick

Cons:

  • It doesn't say how much was damage was caused
17 of 17

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all Ecosystems resources »