Changes in Global Ecosystems

Question 1

Define the term ‘ecosystem’?

Answer 1

A system that environments and their organisms form through their interaction. All components are linked together through nutrient cycles and energy flows.

Question 2

What is the term for ‘plant life’?

Answer 2

Flora

Question 3

What is the term for ‘animal life’?

Answer 3

Fauna

Question 4

Explain why ecosystems are important?

Answer 4

They are home to all the world’s animals and plants.
They provide humans with food, water and the air we breathe.
They are home to all the people on earth.

Question 5

What are natural disasters also known as?

Answer 5

Stochastic Events

Question 6

What is a stochastic event?

Answer 6

An unpredictable or random event that occurs in an ecosystem which can cause changes in populations and communities.

Question 7

Give 5 examples of a stochastic event?

Answer 7

1. Hurricane
2. Wild Fire
3. Earthquake
4. Flooding
5. Tornado

Question 8

What is a biotic event?

Answer 8

An event relating to or resulting from living organisms.

Question 9

What is an abiotic event?

Answer 9

A physical event rather than a biological one that isn’t derived from living organisms.

Question 10

Define the term ‘speciation’?

Answer 10

A term that refers to a biotic event.

Question 11

Explain what speciation means?

Answer 11

It is how a new kind of plant or animal is created. It occurs when a group within a species separates from other members of its species and develops its own unique characteristics.

Question 12

Give an example of speciation?

Answer 12

Galapagos Finches
Different species of finches lived on different islands. Each species developed a unique beak that is especially adapted to the kinds of food it eats.

Question 13

Give an example of a species being reintroduced?

Answer 13

Wolves in Yellowstone National Park

Question 14

What was the ecosystem like in Yellowstone National Park before the reintroduction of wolves?

Answer 14

Without wolves, elks had no predators and therefore doubled in numbers.
The elks overgrazed the entire park leaving no flowers for pollinators, no hiding places for mice and rabbits and no berries for grizzly bears to eat for putting on fat for hibernation.
They also gathered in large herds on riverbanks where their hooves eroded them, causing the rivers and streams to fill with soil. This lead to fish having to live in murky water and beavers not have any clean water to build dams to live in.

Question 15

What happened to the ecosystem after wolves were reintroduced in Yellowstone National Park?

Answer 15

The wolves started hunting elks which decreased their numbers from 17,000 to 4,000.
The elk carcasses meant higher numbers in scavengers like coyotes, eagles and ravens.
Grizzly bears also benefited from elk carcasses and the increased number of berries.
Elk’s avoided riverbanks as they were more likely to get trapped by wolves which resulted in less erosion and trees along them regenerated.
The return of beaver dams created new habitats for fish, amphibians, reptiles and otters.

Question 16

What benefits did the wolves in Yellowstone National Park have on the economy.

Answer 16

In 2005, over 100,000 visitors went to Yellowstone National Park just to see the wolves generating $30 million for the local economy.

Question 17

Define the term ‘ invasive species’?

Answer 17

An organism that is not indigenous to a particular area that causes great economic and environmental harm to a new area.

Question 18

What must a species do to become invasive?

Answer 18

It must adapt easily to the environment, reproduce quickly and harm property, native plants and animals and the economy.

Question 19

State two reasons why invasive species thrive?

Answer 19

1. They outcompete other species for food.
2. There are no predators to hunt them.