Changes in Global Ecosystems Flashcards
Define the term ‘ecosystem’?
A system that environments and their organisms form through their interaction
All components are linked together through nutrient cycles and energy flows
What is the term for ‘plant life’?
Flora
What is the term for ‘animal life’?
Fauna
Explain why ecosystems are important?
Home to all the world’s animals and plants
Provide humans with food, water and the air we breathe
Home to all the people on earth
What are natural disasters also known as?
Stochastic events
What is a stochastic event?
An unpredictable or random event that occurs in an ecosystem which can cause changes in populations and communities
Give 5 examples of a stochastic event?
- Hurricane
- Wild Fire
- Earthquake
- Flooding
- Tornado
What is a biotic event?
An event relating to or resulting from living organisms
Give three examples of biotic factors.
Pathogens
Parasites
Humans
What is an abiotic event?
A physical event rather than a biological one that isn’t derived from living organisms
Give three examples of abiotic factors.
Rainfall
Sunlight
Temperature
Define the term ‘speciation’?
A term that refers to a biotic event
Explain what speciation means?
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
Give an example of speciation?
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
Give an example of a species being reintroduced?
Wolves in Yellowstone National Park
What was the ecosystem like in Yellowstone National Park before the reintroduction of wolves?
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.
What was the ecosystem like in Yellowstone National Park after the reintroduction of wolves?
Wolves started hunting the elks and brought their numbers down from 17,000 to 4,000
Elk kills mean more carcasses for scavengers like coyotes, eagles and ravens
Bears benefited from elk carcasses and the increase in berries
Trees regenerated along riverbanks as elks were more likely to get trapped by the wolves and therefore avoided them
Bigger trees means greater root structures making the riverbanks stronger and less eroded
Return of beavers damns created habitats for fish, amphibians, reptiles and otters
What benefits did the wolves in Yellowstone National Park have on the economy.
In 2005 over 100,000 visitors went to Yellowstone National Park just to see the wolves generating $30 million for the local economy
Define the term ‘ invasive species’?
An organism that is not indigenous to a particular area that causes great economic and environmental harm to a new area
What must a species do to become invasive?
Adapt easily to the environment
Reproduce quickly
Harm property native plants and animals and the economy
State two reasons why invasive species thrive?
- Outcompete other species for food
- No predators to hunt them
Give an example of an invasive species.
Grey squirrels in the UK
Why are grey squirrels classed as invasive in the UK?
Outcompete red squirrels for food
Prolific breeders, up to two litters per year
Carry squirrel pox virus which kills red squirrels
Strip bark off trees to feed on the soft inner layers which severely damages and kills the trees
Define the term ‘community’.
A group of populations made up of different species occupying a shared environment
Define the term ‘resources’.
Physical items a living organism needs to survive
What resources does flora need to survive?
Sunlight
Water
Oxygen
What resources does fauna need to survive?
Food
Water
Oxygen
