Human Impact On The Environment

Deforestation or Cutting Down Trees

What are some causes of deforestation?

-Clearing land for agriculture or farming

-To build homes, schools, shopping centers

-Harvesting wood for fuel

-To make room for live stocks
-To build roads

What are some consequences of deforestation?

- lost of biodiversity

- extinction

- increase in global warming

- lost of cures for diseases and medicines that control illnesses
-less oxygen

Bio means living

Diversity means variety

Biodiversity is a compound word meaning variation of life forms

Should humans try to preserve biodiversity?

People who argue in favor of preserving biodiversity claim that it helps maintain a balance or stability in the ecosystem, preserves possible cure for illnesses and helps maintain an aesthetic balance or beauty in communities.

On the other hand, those who argue against preserving biodiversity insist that extinction is a natural process and humans should not interfere. Additionally, preserving biodiversity is expensive and this money can be put to better use.

ACID RAIN

Normal rain has a pH of 5-5.6

ACID RAIN
is when the pH of rain water is less than 5.
 
What are the causes of acid rain?

• Acid rain is caused by nitrogen oxide and sulfur dioxide released by factories burning fossil fuels (fossil fuels are fuels made by the remains of dead organisms. Ex. coal, oil, gasoline, cooking gas (methane)

What are some consequences of acid rain?

- damage to soil

- damage to buildings

- damage to plants

- kills animals that live in water (aquatic life)

DAMAGES CAUSE BY ACID RAIN

What are some steps that you can take to minimize acid rain?

- vote for politicians who support the environment

- recycling

- start a cyber letter writing campaign

- start an Internet site that addresses this problem

What is global warming?

It refers to the increase of the average temperature of our planet. This problem is caused by excess carbon dioxide that is released in the environment by burning fossil fuels.

Normally, when the sun ray hits the earth, it is reflected back into space. However, excess carbon dioxide in the atmosphere acts as an insulator and traps the sun rays and thereby preventing it from reflecting back into space. As a result, the average temperature of the earth goes up.

What are some consequences of global warming?

- irregular weather patterns (severe droughts, floods, stronger hurricanes)

- increases the rate of extinction- melting of ice caps

- loss of drinking water

DAMAGES CAUSE BY GLOBAL WARMING

What are some steps that you can take to reduce global warming?

- recycle

- take public transportation

- tune up your cars

- start a cyber letter writing campaign

- vote for politicians who support the environment

- plant more trees

- educate others about global warming

Increased Human population causes:

- increased pollution

- loss of habitat that leads to higher rate of extinction

- loss of biodiversity (possible loss of medicines and cures for diseases)

- increased global warming

Using Nuclear Power Plants

Advantages
- low carbon dioxide emissions
- the technology is readily available
- it is possible to generate high amounts of electricity within one single planet.

Disadvantages

- always a chance for accidents
- problem with waste disposal
- nuclear power plants can be targets for terrorist attacks
- waste product can be used for the production of nuclear weapons.

Questions:
How can spraying pesticide on plants affect aquatic life on near by lakes?

• The pesticide can be carried to nearby lakes by rain water

How can the introduction of new species change an ecosystem?

• The new species can bring diseases.
• May not have any predator in the new ecosystem
• Can be a predator to native species and cause extinction of native species

What is it that government can do to prevent the introduction of new species into an ecosystem?

• Government can pass laws preventing the introduction of new species into an ecosystem.
• Can enforce existing laws that regulate the import of new species

What is ecological succession?

• Ecological succession is the orderly replacement of organisms in an ecosystem.

Example of ecological succession

List some environmental factors that are carcinogenic or cause cancer.

• Some environmental factors that cause cancer are: ultra violet light or sun ray nuclear radiation, cigarette smoking, chemicals

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NYS REGENT DIFFUSION LAB

The word transport refers to how things are taken from one place and carry to another. In the diffusion lab, you will observe how cells can take in materials from the environment and also release materials to the environment based on concentration differences without the use of energy or ATP.


Diffusion:
is defined as the movement of molecules from an area of high concentration to an area of low concentration and it requires no energy.  In nature, molecules are always vibrating.  When vibrating molecules collide they move in opposite directions and spread apart.

DIFFUSION LAB IN A NUTSHELL

Part 1: 
In class we tested the permeability of a plastic bag (ARTIFICIAL CELL) filled with water, glucose, and starch. In this context, permeability refers to the ability of the plastic bag to allow some substances to go through it while preventing others from doing that.

Indicator: 
An indicator is a chemical that changes color when it comes in contact with certain substances. When starch comes in contact with iodine, it turns black.

First:
we placed a bag filled with starch solution and glucose in a beaker containing water and iodine (Iodine is a STARCH INDICATOR). See below.

Initial State

RESULTS: 
Below is the appearance of the cell a few hours later....

If the iodine diffuses through the membrane (plastic bag) and mixes with the starch solution, then it will turn BLACK!



Final State

Note: 
The cell membrane is selectively permeable. That is, it has holes in it. It is the size of the holes that determines what goes in and out of the cell.

NOTE:
When starch comes in contact with iodine it turns BLACK. Iodine is a starch indicator.

Ask yourself...

Why did the content of the artificial cell or the plastic bag turned black?

• The iodine molecules diffused into the artificial cell and turned black when it came in contact with starch.

How come the iodine solution in the beaker did not turn black?

• The starch molecules are too large and could not diffuse out of the artificial cell or the plastic bag.

Identify the process.

• The process is diffusion. (NOTE: There was a high concentration of iodine in the beaker and low concentration of iodine inside the plastic bag so the iodine moved from high concentration (in the beaker) to low concentration. (in the plastic bag)

"How would the result be different if the iodine was placed in the bag and the starch and the glucose were placed in the beaker?"
(Drawing the scenario might make it easier to answer the question)

Some substances that diffuse freely across the membrane are oxygen, carbon dioxide and water.

Part 2: OSMOSIS in Red Onion Cells:

OSMOSIS
is the diffusion of water through a cell membrane. When water goes through the cell membrane, no matter what direction, in or out, it is called "osmosis".

In class we observed osmosis in plant cell by:

• FIRST putting a drop of water on a slide.
  
• Putting a piece of red onion tissue (the outer skin) on top of the water.
• Placing a cover slip on top of the tissue and press firmly.

When viewed under high power in the microscope, this is what it looks like!

Then to demonstrate osmosis we:

• Put a drop of salt water on one side of the cover slip
  
• Place a piece of paper towel on the other side of the cover slip.
  

This is how the cells looked after the cells exposure to salt water. Water diffused out of the cell

In another example of Osmosis we reversed the process by:

• Putting a drop of fresh water on one side of the cover slip.
• Placing a piece of paper towel on the other side of the cover slip.

Below is a picture after the water diffused back into the cell.

Observing Osmosis in Elodea

With Fresh Water

Magnified 400 X



With Salt Water

Magnified 1000 X

Osmosis in White Onions

Fresh water

400 X


With Salt water

400 X

Elodea Osmosis Lab Power Point

CHECK OUT THIS INTERACTIVE
CLICK HERE:  "OSMOSIS"
Vocabulary

Homeostasis:
is defined as a series of processes that help maintain an organisms stable internal environment.

Diffusion:
is the movement of particles from an area of greater concentration to an area of lesser concentration and it requires no energy. During diffusion, particles continue to spread until they are evenly distributed.

Osmosis
Is the diffusion of water through a cell membrane.

QUICK REVIEW! NOTE: The cell membrane also controls what goes in and out of the cell by active transport, using special transport proteins.

Active Transport:
is the movement of particles from an area of low concentration to an area of high concentration and it requires energy (ATP).

ANIMATION OF ACTIVE TRANSPORT


Let us review to other cellular processes, photosynthesis and cell respiration.
"An easy way to remember the formula for photosynthesis and cell respiration"

-What do plants need? (Plants need water, carbon dioxide and light)

-What do plants make? (Glucose and oxygen)

The Formula for photosynthesis 
Water + CO2 + light, change to glucose + O2 (photosynthesis takes place inside the chloroplast)

To obtain the formula for cell respiration
-Reverse the formula for photosynthesis and replace light with ATP


The formula for cell respiration:
glucose + O2 change to H2O +CO2 +ATP (cell respiration takes place inside the mitochondria)

All of the chemical reactions that take place inside an organism require the assistance of enzymes.

-Enzymes are biological catalyst that speed up the rate of chemical reactions without becoming part of the final product. 

-Enzymes are proteins and all proteins have specific shape. They interact with molecules called substrates. They must fit the substrate in order to make reaction go forward. 

NOTE:
Each chemical reaction that takes place in the body requires a different enzyme.

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