Name:____________________________ Date:__________________ UNIT 3 Student Notes

3.1 How Changes Occur Naturally in Ecosystems

Introduction

When an organism is born, it belongs to a species, but it also is born with __________________________ characteristics.

• Like humans with __________________coloured eyes and _____________ heights.

• Sometimes, these unique characteristics give that individual an ______________ within their niche. ie, a salmon with a slightly larger tail may be able to swim a little faster or a little farther in a river.

Natural selection is the process where individuals with advantages are ______ ______________________ and pass along their traits.

• Those with _______________________ characteristics have_______________ chance to reproduce and pass along their traits. Ie. A salmon with a smaller tail may never have a chance to spawn because it can’t swim to the correct location.

How Organisms Adapt

The _______________________________, off the coast of Ecuador, are perhaps the most famous example of natural selection.

• Many species on these islands are _____________________ to each other, and also to species on the South American continent.

o There are thirteen species of finch on the islands. o Each is descended from a finch species from the mainland. o Each species has ________________________________________

_______________________________________that allows them to thrive in their own niche, and not compete with other finches for resources.

_____________________________ is the term for this type of natural selection.

Name:____________________________ Date:__________________ • Many different species appear from one original species.

Galapagos finches

Primary Succession ___________________________________ refers to the changes in the biotic characteristics in an area over time.

• Over time, the life in an area changes • There are two types of ecological succession________________________ _________________________________.

1. Primary succession - begins with nothing but _________________________

• Where glaciers scrape away dirt, or a volcano erupts • Wind carries spores of lichens and organisms that can survive and

eventually, combined with the weathering of rock, _______________________________

• The first organisms to survive and reproduce are _________________________.

o Pioneer species alter the abiotic and biotic environment in some way. o Soil improves, plants are able to grow, animals begin to appear.

• Primary succession occurs in this way in all parts of the world. • This stage can last for hundreds of years, until a mature community

eventually forms.

Name:____________________________ Date:__________________ Secondary Succession

2. Secondary succession - after a major disturbance in an area _______________ ____________________________ and once had living organisms.

• ______________________ are the most common reason for secondary succession.

• The soil remains for plant growth, and contains seeds, micro-organisms, earthworms and insects.

• Secondary succession is much more rapid than primary succession. o There is already soil, seeds and insects, so

_______________________________________________.

Mature communities are very ____________________, and can appear to be unchanging over long periods of time.

• These are also known as ______________________________, but “mature” correctly implies that there are still changes occurring, albeit more slowly.

How Natural Events Affect Ecosystems

Many disturbances can affect mature communities.

1. _________________________ • Water is not contained within natural or artificial barriers. • Generally occurs in locations where water levels can change rapidly. • It can result in __________________________ as well as the spread of

pollutants and harmful bacteria associated with wastes. • Climate change and global warming may be ___________________

incidents of flooding.

Name:____________________________ Date:__________________ • A tsunami occurs when huge waves, from large earthquakes or volcanic

eruptions, floods coastal areas.

2. ______________________ • Occurs when an area receives a lower than average amount of rainfall over a

very long period of time. • Prolonged drought can have severe effects on organisms.

3. _______________________ • Many insects play important roles in their ecosystems. • Even insects that appear destructive, such as the mountain pine beetle,

actually play a role in the renewal of the forest. o The beetles even have a ______________________________ with a

species of fungus that inhibits the trees’ ability to use resin for protection.

• However, when normal conditions are ________________________, infestations can occur.

o Trees can be stressed from overcrowding, drought or animal grazing, and do not resist the insects as effectively.

• A warmer climate, and lack of forest fires, allows the insects to spread much more effectively than in the past.

• Not only are the trees affected, but so is the entire forest ecosystem, as well as any human industries relying on the forest.

3.2 How Humans Influence Ecosystems

Introduction

____________________________ are special ecosystems that contain completely waterlogged soil for long periods of time.

• Not only do wetlands contain ________________________________, but they also filter many impurities out of the water that slowly flows through them.

o For this reason, they are sometimes called the “kidneys” of the Earth.

• Because they hold large amounts of water, they can help__________________flooding.

Name:____________________________ Date:__________________ Human encroachment has caused many BC wetlands to disappear.

• In the past 100 years: Up to ________ of the wetlands in the lower Fraser Valley have been lost.

• Up to _______ of the wetlands in the South Okanagan have been lost.

Wetlands are vital ecological features in British Columbia.

Understanding Sustainability

“__________________” is a word that is used often, and can be defined in more than one way:

• “The ability for an ecosystem to sustain ecological processes”. o These processes enable biodiversity and keep the ecosystem healthy.

• “People using an ecosystem to meet their needs today without reducing the

function or health of the ecosystem in the future”. o Sustainable practices ______________________, healthy ecosystems. o Economic opportunity, biodiversity and ecosystem health are all

possible.

Effects of Land & Resource Use “________________” refers to how humans use land around us for urban development, agriculture, industry, mining and forestry.

• All of the land around us, even in cities, was once a part of an ecosystem.

“_________________” refers to the ways we obtain and use naturally occurring materials.

• Most products you use every day involve the use of some natural resources in their production.

If the land and resources are not used directly, they are often processed and exported to other places for use. Habitat Loss The use of land and resources have seen humans encroach on natural ecosystems very aggressively in the past 150 years.

• As a result of this expansion, habitats have been ______________________. • “__________________” refers to to loss of habitats due to human activities.

Name:____________________________ Date:__________________ • “_____________________” is the splitting of large habitats into many

smaller ones, resulting in disrupted natural activities for plants and animals.

Habitat loss (top left) and habitat fragmentation (bottom left) reveal the effects of human activities on ecosystems.

Effects of Deforestation ______________________ is the clearing or logging of forests for human use.

• The resulting barren land is never reclaimed or replanted. • The agricultural crops that are planted are often one species =

____________________ o This reduces biodiversity, and leaves the crop vulnerable to pests or

disease. o ___________________________, of many plant species, are more

economically and biologically diverse. • Deforestation is still occurring in many tropical rainforests. • Deforestation results in ___________________________.

o Soil degradation is when moving wind and water _______________ ___________________ and leave bare land behind.

o Topsoil, the upper layer of soil, is where most of the nutrients, water and air are found for plant growth.

Name:____________________________ Date:__________________

Effects of Agriculture If fields are left exposed during non-planting seasons, water and wind erosion can occur. In areas like southwestern BC, the soil can become ______________________.

• Soil particles are squeezed together and become compacted.

o This is due to _______________ _____________________.

• There is no room for water or air to enter the soil.

• Water then ______________ the soil instead of _______________________.

o Loss of water, increased erosion and the addition of farm fertilizers and pesticides to the ecosystem.

• Aeration, which involves removing small plugs of soil, loosens soils and can reduce run-off.

Farm animals, such as these cows, can compact soils.

Effects of Resource Exploitation Resource exploitation = resource use

• Humans depend on resource exploitation for jobs, materials, food, shelter and energy.

• Exploitation can lead to ________________________________________ ____________________________________________________________.

o Contamination is the introduction of harmful chemicals or micro-organisms into the environment.

o Many mining and resource exploitations require___________ efforts. Reclamation attempts to reduce environmental impacts of

exploitation, and tries to restore the original (or at least functional) habitats.

• ____________________ is the extraction of resources until they are gone. o This can result in extinction, such as with the passenger pigeon.

Name:____________________________ Date:__________________ o Food webs can be greatly affected over long periods of time o The overexploited species could be a _________________________.

Resource Management In Aboriginal cultures, __________________________________ is passed down from generation to generation.

• This knowledge reveals what _____________________ were like, and also how the ecosystem and humans__________________.

• Knowledge is found in stories, songs, cultural beliefs, rituals, community laws and traditional practices.

• Current ecological restoration and usage guidelines often involve this traditional knowledge from Aboriginal representatives.

o Traditions such as the “_________________” allow for ecological renewal.

o Fire suppression, enforced in BC for over 100 years, has led to recent issues like the ___________________________________________ ________________________________________.

3.3 How Introduced Species Effect Our Ecosystems

General Information _____________________ are plants and animals that naturally inhabit an area.

• Because of the immigration to North America by many people from other continents over the past 400 years, many new species have been ______________________accidentally (and on purpose) here.

o These new species of plants and animals are called _______________ _____________________.

o Aka __________________, non-native species, exotic species or alien species.

o Many of these species are harmless, or sometimes even beneficial. o _________________________, such as Purple Loosestrife, negatively

impacts native species, and often reduces biodiversity as a result.

The European leaf-feeding beetle (left), and the Purple Loosestrife

Name:____________________________ Date:__________________

Impact of Introduced Species Invasive species often take advantage of their new habitat.

• They may ___________________________________________________ _____________________________________.

• __________________: while the native species have an established balance, the invasive species can throw off this balance.

• __________________: if the invasive species is a predator, it may have a huge advantage, as the native species may have no methods to survive.

• ____________________________: by weakening certain species, a micro-organism invading an ecosystem can drastically alter the entire ecosystem and the niches within it.

• _____________________________: some invasive species can change the physical structure of the ecosystem by digging, burrowing, blocking sunlight or changing the chemistry of the ecosystem.

Invasive Species in BC

American Bullfrog European Starling Eurasian Milfoil Norway Rat Saving an Ecosystem Under Siege It often takes human intervention to save established ecosystems.

• The Garry Oak Ecosystem Recovery Team (GOERT) is trying to save several areas of the Garry Oak ecosystem in BC.

Name:____________________________ Date:__________________ • __________ of the original ecosystem has been lost to urban development,

and the remaining 5% is threatened by___________________________. • Scotch broom, English ivy and other plant species are its biggest threats.

GOERT has representatives from many groups.

• The BC government, First Nations, conservationists, scientists and businesses believe this work is critical.

• Garry Oak forests may be better suited to survive in the future than Douglas fir forests.