Biology Unit Chapter 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 Activity  Form groups of 3  As 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?  Definition  Example

How Humans Influence Ecosystems Wetlands 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   