Biology UnitChapter 3

Notes #2

Agenda Sign up for rewrite during work time Quiz on Wednesday (3.1 and 3.2)

Today Review of yesterday (practice problems) Group activity Notes Research assignment

Review Natural selection Adaptive radiation

Ecological succession Primary Secondary Climax communities

Natural phenomena that change ecosystems

Go over practice questions from last day

Group ActivityForm groups of 3As a group answer these questions:

1. How do humans influence ecosystems?Give two examples

is it positive or negative? What part of the ecosystem is affected? Is there a way to fix it if necessary?

2. What does sustainability mean to you?DefinitionExample

How Humans Influence EcosystemsWetlands are an example of an important ecological function, both for the organisms that live within it and for humans

Wetlands are characterized by Waterlogged soil for all or part of the year Unique plants and animals Ability to filter wastes from water Regulate nitrate and carbon levels Retain large amounts of water (prevent floods)

One type of wetland is a peat bog. These were found extensively in the Lower Mainland as large networks

Humans use the bogs for Food: wild blueberries and cranberries peat: for gardens and nurseries Commercial crops

Human’s have manipulated wetlands for these uses Burning bogs to keep trees from growing Mining the peat to sell Turning bogs into commercial crop fields Destroyed to be replaced by parking lots,

subdivisions, garbage dumps, agricultural fields, shopping malls

Wetlands that took thousands of years to form have been destroyed over the last 100 years

Lower Fraser Valey: 50-70% wetlands gone South Okanagan: 85% wetlands gone

By destroying wetlands Carbon dioxide and methane are

released back into the atmosphere (climate change)

Decreased biodiversity Decreased water filtration

We need to find a balance between our needs and the needs of ecosystems…

Sustainability the ability of an ecosystem to sustain

ecological processes Using the resources of an ecosystem to

meet our needs today without reducing the function and health of that ecosystem

Sustainability has to do with how we approach ecosystems and the way we use and support them.

Examples of how humans influence ecosystems. Land use and resource use Habitat loss Deforestation Agriculture Resource exploitation

Land Use and Resource Use

Land use means the way we are using the land around us. This includes things like roads, cities, agriculture, industry, mining and forestry

Resource use means the way we obtain and use things like soil, wood, water, gas, oil and minerals

Humans have always used both the land and resources to meet their needs… so how does this use influence ecosystems?

Habitat Loss Human populations have grown quickly over time and

those people have to be put somewhere. This means that ecosystems are destroyed or fragmented to make way for people.

Habitat loss: the destruction of habitat, usually due to human acitivity.

Habitat fragmentation: the division of habitats into smaller isolated fragments.

Both of these affect plant populations, seed dispersal, wildlife movement, and plant and animal reproduction.

Sustainable approach… Wetland areas within the city Forest management activities to restore areas

Both of these affect plant populations, seed dispersal, wildlife movement, and plant and animal reproduction.

Sustainable approach… Wetland areas within the city Forest management activities to restore areas

Deforestation Forests are logged or cleared for human use

and never replanted.

Reduces plants and animals living in an ecosystem and causes soil degradation

Erosion of topsoil

Sustainable approach… Ex. Coffee farms in northeastern Brazil

Instead of clearing land and making monoculture fields, farmers grow the coffee plants in among other plants. The coffee plants benefit from the shade and nutrients and protections of the other plants. The farmer has more than one crop to depend on.

Agriculture Often fields are left bare during non-planting

season leading to unhealthy soil: Soil erosion Soil compaction

These processes reduce the movement of air and water in soil making it less healthy and able to support organisms.

Resource Exploitation The use of resources can be

considered exploitation: It can lead to habitat loss and

soil degradation Water contamination by

chemicals Mining, forestry, fishing

Sustainable approach… Mine reclamation involves the

restoration of land and development of water treatment to remove harmful chemicals Often plants are used to remove

contaminants from mine sites

Overexploitation The use or extraction of a resource until it is

depleted

This results in extinction: the dying out of a species Ex. Passenger pigeons hunted to extinction by early

North American settlers Ex. Yellow tuna and Atlantic cod have been overfished

and reduced by 90%

Over exploitation reduces numbers and reduces genetic diversity… Lower resistance to disease Lower ability to cope with change

P.132 kelp forests and food webs

Resource Management and Traditional Ecological Knowledge Traditional Ecological Knowledge (TEK)

the thorough understanding of the plants, animals, and natural occurrences of an area that an indigenous people have

This is passed down through generations, reflecting centuries of learning

This reflects local climate, resources, biotic and abiotic characteristics and animal and plant cycles.

Example: Spring burning of prairie grasslands by the Cree in northern Alberta This was commonly done before Europeans

settled Controlled burning renewed grasslands, recycled

nutrients, and allowed plant growth to increase Sustains grassland for grazers, attracted

carnivores, and moose

Research Assignment Choose one topic to research

Disease Pollution Habitat destruction Exploitation of resources

Find two articles about how your topic affects ecosystems.

Write a summary report including What your topic is and why you chose it The names and authors of the two articles A 4-5 sentence summary for each article What you think is the most important part what you

read What you think should be done about the problem

Possible websites http://www.wri.org/stories/ecosystems http://www.nwf.org/search.aspx http://www.sciencedaily.com