science 9 unit a: section 4 - wordpress.com · 2016-12-10 3 science 9 unit a section 4.0 5...

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Science 9 – Unit A: Section 4.0

Science 9 Unit A Section 4.0 1

Textbook pages 57 – 65


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• Species and ecosystems on Earth are being stressed by urbanization and the expansion of human industries such as agriculture and forestry.

• The extinction of some species, the decrease in population of other species, and the degradation of ecosystems reduces biological diversity on Earth.

Science 9 Unit A Section 4.0 3#1

• The dodo was a flightless bird that had no predators.

• Portuguese explorers that discovered them brought with them cats, rats, dogs, and pigs, all of which ate the birds and their eggs.

• The dodo became extinct within 200 years of first human contact.


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• Ecosystem Diversity

• Differences where

interactions take place.

• Species Diversity

• Differences between

different organisms within

a GENUS.

• Genetic Diversity

• Differences at the cellular

level.


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• Extinction is the

disappearance of every

individual of a species from

the entire planet.

• A natural part of Earth’s history.

• Scientists estimate that 99% of

all the species that have ever

existed are now extinct (mostly

by mass extinctions).



The woolly mammoth

coexisted with early

humans. It disappeared

from its mainland range

about 10,000 years ago,

most likely through

climate change and

consequent shrinkage of

its habitat, hunting by

humans, or a combination

of the two. Cloning the

mammoth is not yet

possible because of the

degraded state of the

genetic material that

remains.

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• Most extinction takes place over long periods of time, but the

RATE of extinctions is rising, and this reduces the biological

diversity of our planet more rapidly.


Javan Rhino; only ~60 remain in

Indonesia due to illegal overhunting

The dodo bird; extinct

within 200 years of first

human contact

#3

• Extirpation is a local

extinction, or the

disappearance of a

species from a particular

area.

• Example: Grizzly bear


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Example: The woodland caribou

(Boreal forests of northern Alberta)

Example: The swift fox

(Alberta; restoration is underway and is now recovering)


• In immediate danger of

extinction or extirpation.

• Example: Red panda

• You can find the red

panda at the Edmonton

Valley Zoo!


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• Likely to become

endangered if their

current declines are not

reversed.

• Example: Wood bison


• Particularly vulnerable to natural events or human activities.• Example: Wolverine

• The wolverine, a solitary animal, has a reputation for ferocity and strength out of proportion to its size, with the documented ability to kill prey many times larger than itself!

• Facing a steady decline in the face of trapping, range reduction and habitat fragmentation.


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• In the past, most extinctions and extirpations were due to

natural causes, such as:

i. Catastrophic events (volcanic eruptions, earthquakes,

floods, fires)

ii. Lack of food due to overpopulation

iii. Disease


• Overspecialization is another natural cause of extinction. It occurs when a species has adaptations that suit them to only a narrow set of environmental conditions.

• This probably happens because the environment that the organism inhabits remains unchanged for a very long time.• Example: Giant panda, which only

eats bamboo shoots


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• A generalist is an organism that is able to utilize different foodsources or living environments and is therefore able to flourish in many habitats.

• Example: Mice, which can adapt to practically any environment and consume a variety of foods


• Because human populations continue to grow, and require

land for houses and food production, human activity is now

the leading cause of worldwide species loss.

i. Habitat destruction

ii. Introduction of non-native species

iii. Over-hunting


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• Construction of buildings,

agricultural development

(i.e. clear-cutting in the

Amazon Rainforest to

create farmland), logging,

and the damming of

rivers and pollution (i.e.

pesticides, herbicides, and

fertilizers) all change

environments.


• When introduced species

use the same resources as

native species, they

compete with the native

species and cause the

number of native species

to decline, simply because

there is less of everything,

and also because the

introduced species has no

native predator.


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• Over-hunting was the major cause of the decline and eventual extirpation of the plains bison over most of its range, and of the extinction of the passenger pigeon (hunted for sport).

• Sometimes species were hunted to deliberately extirpate them. Black-tailed prairie dogs were considered a great menace to farmers and ranchers in the 1930s because they ate grain and dug holes causing cattle and horses to break legs.


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• Extinctions and extirpations reduce biological diversity.

• Extinctions reduce the number of species on the planet.

• Extirpations reduce biological diversity in areas from which

the organism has disappeared.

• Example: Recall the over-hunted black-tailed prairie

dogs. Well, these prairie dogs are the major source of

food for black-footed ferrets, which are now one of

the most endangered animals in North America.


• Textbook

• Check and Reflect

• Page 65

• # 1 – 7

• Read Topic 4.2

• Page 66 – 71


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• My brother’s dog!

• Buddy is a purebred

English Labrador.

• This is him at about 1

year old!


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• Recall that in natural selection, the environment “selects” traits.

• Organisms with the traits that are best suited for the changing environment

will be more likely to survive and reproduce, thus passing on that trait to

their offspring.

• This process usually takes many generations to occur.


• Artificial selection is the process of humans selecting and

breeding individuals with desirable traits to produce offspring

that have these desired traits.

• Only individuals with the desired trait (i.e. strong muscles, fast runners,

shiny fur coat, etc.) will be allowed to reproduce.

• This process applies to plants and animals, both of which can be bred to

possess desirable traits.


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Plow Horse Racing Horse



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• Increase food production

• To create ornamental

garden plants

• Medical research

• To create “ideal” pets

and domestic animals


• Biotechnology is the use of living things to make agricultural,

industrial, or medicinal products.

• It is a process of intervention using ‘low-tech’ or ‘high-tech’

technologies, such as:

i. Cloning (creating a genetically identical copy of an organism or its

cells)

ii. Artificial reproductive technology (any artificial method of joining a

male and a female gamete)

iii. Genetic engineering (directly altering the DNA of an organisms)


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• In artificial insemination, sperm are harvested from a bull with desired characteristics and are inserted into many femalecows.

• The advantage of this technology is that the bull’s sperm can be in several places at once and more cows can be inseminated.


• Can you think of real-life situations where artificial insemination

may be required to impregnate a woman?

• Consider a male with erectile dysfunction (i.e. produces too little sperm)

• Consider a quadriplegic male who wants to start a family with his wife

• Consider 2 women who want to start a family (without the presence of a

male)


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• In this technology, sperm from a prize bull and eggs from a prize cow are harvested from the animals.

• In a laboratory, the eggs and sperm are placed in a Petri dish, and the eggs are fertilized. This produces many more embryosthan could be produced naturally.

• Each embryo is implanted into adifferent cow. These cows will eventually give birth to many calves, all of which will be brothers and sisters.


• Can you think of real-life situations where in vitro fertilization may be required to impregnate a woman?• Consider a male with erectile dysfunction

(i.e. produces too little sperm)

• Consider a quadriplegic male who wants to start a family

• Consider 2 women who want to start a family (without the presence of a male)

• Consider a female who doesn’t release eggs (i.e. does not have a regular period/menstrual cycle)

• Consider a female who cannot carry her own baby in her own womb and uses the assistance of a surrogate mother


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• Genetic engineering refers to any technology that directly alters the DNA of an organism.

• Genetic engineering is a rapidly developing science, and every new advance increases our ability to control the characteristics of organisms.

• Many of the genetic engineering techniques involve inserting a gene from one species into another species.


• For example, these are peanut leaves. In the top photo, the leaves have been extensively damaged by a certain type of larvae that feeds on the leaf.

• Scientists genetically altered the DNA of these leaves by injecting some of the genes of a certain type of bacteria into the DNA of the leaves. This bacteria acts as a natural pesticide and kills most of the larvae, allowing the plant to grow and preventing damage to its leaves.


http://upload.wikimedia.org/wikipedia/commons/1/1d/Bt_plants.png

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Risks in Animals

• Reducing genetic variation

within a specific population

• Less resistance to disease

• Birth defects

• Unsuccessful pregnancies

• Deaths among clones

• Abnormalities

Risks in Plants

• Resistance to herbicides

• Reducing genetic variation

• Interbreeding with weeds

results in weeds’ offspring

that are also resistant to

herbicide



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• Textbook


• Page 71

• # 1, 2, 6, 7

• Read Topic 4.3

• Page 72 – 76


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• The conservation of biological diversity requires the elimination

or reduction of the adverse impacts to biological diversity that

result from human activity.

• In order to promote biological diversity, the Canadian

Biodiversity Strategy (Canada signed it in 1992) focuses on in-

situ and ex-situ conservation, along with promoting the

sustainable use of resources and an ecological approach to the

management of human activities.


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• In-situ conservation

refers to the

maintenance of

populations of wild

organisms in their own

functioning ecosystems.

• It allows the ecological

processes of an area to

continue undisturbed.


• Examples:

• National Parks (i.e. Banff

and Jasper)

• Linking protected areas

together (Yellowstone to

Yukon Conservation

Initiative)

• Wagner Natural Area

(west of Edmonton; a

protected land and mini-

boreal forest)


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• Ex-situ conservation refers to the conservation of components of biological diversity outside of a natural habitat.

• In some cases, ex-situ conservation offers the only chance of survival for some endangered species and plays an important role in conserving economically valuable genetic resources for forest, aquatic, and agricultural purposes.


• Examples:

• Seed banks (which store seeds from the many varieties of

crop plants)

• Today, the world’s seed banks are administered by an

international group of scientists, known as the International

Plant Genetics Resources Institute (IPGRI). IPGRI has

instructed Canada to maintain the seed bank for barley

and oats.

• Sperm and egg banks

• Zoos


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• Textbook


• Page 78

• # 1, 2, 3, 4, 6, 7

• Unit A Review Handout &

Study Guide


science 9 unit a: section 4 - wordpress.com · 2016-12-10 3 science 9 unit a section 4.0 5...

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