Lesson 4 - Effects of Human Activity Flashcards
What is 1 positive and 1 negative of vegetation removal?
- Sometimes vegetation is removed for a good reason (e.g. there are native plants that are being affected by weeds)
- Most of the time, though, trees are cut down to make way for grazing land for animals or we cut down trees to make paper which is really bad for the forest
What percentage of plants and animals on Earth live in forests?
70%
What happens when forests are cleared?
Loss of habitat for many plants and animals
What is biodiversity?
Having a range of different plants and animals
What is saline?
‘Saline’ is salty water.
What happens to salt in soil if the land is left alone?
Most of it sinks deeper into the ground
What is the effect of artificial rain on soil salt levels?
There’s too much water for the land to deal with
What are irrigation systems used for?
To artificially make it rain using massive sprinklers or hoses
What would happen if we left the land alone?
If we left the land alone, it would
rain a bit, the sun would evaporate the water and the salt would stay deep in the ground.
What are 3 ways to artifically make it rain?
Irrigation systems, basically massive sprinklers or hoses that drip constantly
What natural processes help manage salt levels in soil?
Rain and evaporation
What are the 3 steps for salty groundwater?
- Irrigation soaks the soil, so the water seeps deeper into the ground than normal
- The sun evaporates surface water, drawing the deeper water (now full of salt) up to the surface.
- The soil is now too salty to grow anything.
What did BHP do in Papa New Guinea?
BHP decided that the people of Papua New Guinea near the Ok Tedi mine were worthless, so they pumped millions of tons of poisonous mining waste directly into their water supply which resulted in birth deformities and loss of habitat
What is fracking?
a special type of mining where they pump chemical water deep into the ground to fracture the rock and get oil out
What big explosion happened from mining in the ocean and when?
When the Deepwater Horizon drilling rig in the Gulf of
Mexico (where they drill under the ocean) exploded in
2010, over 700 million litres of oil was released into the water.
