The Environment and Change Over Time

How Changes to the Ecosystem Affect Population

7.ECO.7 Use empirical evidence from patterns and data to demonstrate how changes to physical or biological components of an ecosystem (e.g., deforestation, succession, drought, fire, disease, human activities, invasive species) can lead to shifts in populations.

Short Term Changes

• Changes that occur quickly in an ecosystem and affect organisms immediate

• Does not give organisms time to adapt to changes 

• Forces populations to move or possibly risk death

• Can cause the population to decline

Examples of Short Term changes

• Drought

• Flood

• Volcanic Eruption

How Do Short Term Changes Affect Organisms?

Drought –

the severe lack of rainfall causes producers to die which eventually reduces food sources for all other organisms

Flood –

organisms that are unable to escape the rising water are swept away and drown

Volcanic eruption –

gas, ash, and lava covers a large area and destroys shelters, food sources, and habitats of many organisms

​Adaptation

When organisms can not adapt (change over time) to their environment their population decreases or become extinct

Multiple Choice

A fire destroys all of the trees and plants in the forest. How might this affect the birds in the area?

• The birds will plant seeds and grow new trees.

• The birds will have more food to eat.

• The birds will plant seeds and grow new trees.

• The birds will have no place to build their homes.

Multiple Choice

All of the following are examples of environmental changes that can be caused by humans except - 

• clearing land for housing developments
• pesticides
• volcanic eruption
• pollution

Long Term Changes

• Changes that occur slowly over time and affects organisms over several generations

• Gradual changes that allow organisms time to adapt 

• Organisms become better adapted to survive in their environment

Multiple Choice

An organism that cannot adapt to changes in the environment will most likely -

• produce more offspring

• die

• change its traits to survive

• store more food

Examples of Long Term Changes

• Climate change

• Pollution

• Deforestation

• Each of these things can be cause by human interference

How do Long Term Changes Affect Organisms?

Climate change –

a change in climate patterns that can cause a change in migration patterns, nesting, and hibernation of many different species 

Pollution –

chemicals, pesticides, and fertilizers can poison air, soil, and water over time

Deforestation –

destruction of a forest which contributes to habitat destruction of a large number of species

Urbanization - an increase of an urban (city) population

A pathogen that can cause population to decrease and affect how organisms interact with each other

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​Disease

A animal that is not native to the area that does not have any natural predators

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​Invasive species

Multiple Choice

The ICE AGE is

• Short Term Environmental Change

• Long Term Environmental Change

Multiple Choice

URBANIZATION is

• Short Term Environmental Change

• Long Term Environmental Change

Multiple Choice

A WILDFIRE is

• Short Term Environmental Change

• Long Term Environmental Change

Multiple Choice

A BLIZZARD is

• Short Term Environmental Change

• Long Term Environmental Change

Environmental Changes Vocabulary

• adaptation - how organisms adjust to a new environment or make changes to their current environment

• climate change - a change in global or regional climate patterns

• conservation - to prevent the wasteful use of a resource

• ecosystem - all of the living and nonliving things that interact in an area

• environment - the setting or habitat in which organisms live

Environmental Changes Vocabulary

• long term environmental changes - changes that occur slowly over time and affect organisms over several generations

• pollution - the contamination of air, water, or soil by substances that are harmful to living organisms

• short term environmental changes - changes that occur quickly in an ecosystem and affect organisms immediately

• succession - the gradual growth of new organisms in an ecosystem

• urbanization - an increase of an urban (city) population