4.8: City Life
pg. 148
Key Concepts:
1. Urban ecosystems depend on natural
ecosystems for food and materials.
Do you live in an Urban or rural area?
The Urban Ecosystem
- Urbanization is the buildup of rural or natural lands in
to urban area, as more people move to existing cities
or suburbs.
- Urbanization can cause many problems; such as;
“Heat Islands”.
 Areas that are warmer then surrounding
rural areas.
Difference between Urban and Natural areas;
Urban
- Classified as “urban ecosystems’
- Built on a layer of concrete and
asphalt.
- Combination of artificial and natural elements
Natural
- have living carpets of grass, trees and other plants.
.
- In cities most of the natural vegetation has been
replaced with human structures.
- Roads, sidewalks, and buildings
- Limited plant life; parks with grasses and trees,
usually monocultures
- Natural water and nutrient cycles are places with
sewers and waste treatment plants.
Tables 1: Comparison of Urban and Natural
Ecosystems.
Greener Cities
Ecological Footprint: is a measure of the land area
required to sustain a given population of humans.
Case Study: Vancouver, British Columbia
Case Study: Iqaluit, Nunavut
Check Your Learning:
Questions 1 – 6, pg. 151
Wrap Up:
- Urban areas are places in which homes and other
buildings are crowded together, with little open space.
- People who live in urban areas rely on outside
ecosystems for most of their resources.
- Living in urban ecosystems can benefit the
environment because many people living close
together can reduce consumption of energy, resources,
and space.
- A city becomes more green, as it reduces its impact on
the environment.
Chapter 4 Summary
1. Some ecosystems are designed, created, and
maintained by humans
- Some humans spend little time in natural
ecosystems.
- Humans can change natural ecosystems, but we
cannot change our dependence on them.
- A farmland is an engineered ecosystem.
2. Agricultural practices disrupt natural
biogeochemcial cycles.
- On a farm, a limited number of species
interact.
- Humans must manage the water and nutrient
supply for farms.
- Farmers commonly apply fertilizers to replace
soil nutrients.
3. It is important to keep Earth’s soil healthy.
- The four main parts of soil are minerals,
organic matter, air, and water.
- Soil health depends on the amount and
availability of nutrients.
- Fertilizers are beneficial but can create
problems for the environment.
4. Pesticides are used to reduce crop losses due
to insects, weeds, and other pests.
- There are no “pest” in nature. There are simply
producers, consumers, and decomposers.
- Most pesticides are poisons that control or
eliminate pests.
5. Pesticides have ecological costs.
- Pesticides can pollute the soil, air, ground
water, and aquatic ecosystems.
- Pesticides can harm organisms that are not
the intended target.
- Some pesticides build up in the bodies of
individual organisms and move up through the
food chain.
6. Urban ecosystems depend on natural
ecosystems for food and materials.
- Urban ecosystems combine artificial and
natural elements.
- In a large city, most of the natural vegetation
is replaced by human structures.