Download Unit A * Biological Diversity

UNIT A – BIOLOGICAL
DIVERSITY
Outcomes
4. identify the role of variation in species survival under
changing environmental conditions
6. describe examples of variation of characteristics within
a species
13. distinguish between, and identify examples of, natural
and artificial selection and the technology involved
VARIABILITY AND SURVIVAL
• Variability is important if the environment of a species
changes.
• Environmental change can be from humans, adding a
predator in, change in climate or the introduction of a new
disease.
• Example: Peppered Moth
VARIABILITY AND RESISTANCE
• Variability is good for species to survive environmental
changes but it can also be negative for humans when
they want to eliminate something.
• Certain strains of bacteria have become resistant to
antibiotics and if the trend continues antibiotics may no
longer be effective.
• Can you think of other examples of variability being a
negative or positive thing?
NATURAL SELECTION
• Natural selection occurs when the environment “selects”
which individuals within a species will be able to survive
long enough to reproduce.
• "Survival of the fittest" is a phrase that originated from
an evolutionary theory as a way of describing the
mechanism of natural selection.
• Natural Selection is often seen as a survival for the
desirable traits. This is what was seen by Charles Darwin
and his finches.
EXAMPLE OF ADAPTATIONS FOR
SURVIVAL
• http://www.edumedia-sciences.com/en/media/562-birds-
beaks
• http://www.edumedia-sciences.com/en/media/499-
environmental-adaptation-and-homology-in-the-skeleton
•
Think About it!
• What do we mean about survival of the fittest?
• Complete bunny scenario
• https://phet.colorado.edu/en/simulation/natural-selection
• https://www.youtube.com/watch?v=jHQcKUJGZSM
Outcomes
6. describe examples of variation of characteristics within
a species
8. distinguish those characteristics that are heritable from
those that are not heritable, and identify characteristics for
which heredity and environment may both play a role
9. identify examples of dominant and recessive
characteristics
Class Exploration
• Working in groups, complete the table and test the
following features of your group members
Characteristic
dimples
eye colour
earlobe
Option 1
dimples
present
brown/green
detached
Option 2
no dimples
hair colour
brown/black
blond/red
second digit
finger
skin pigment
thumb
short
long
freckles
bends back
tongue
can roll
no freckles
does not bend
back
cannot roll
blue/grey
attached
Heritable and Non-Heritable
Characteristics
• Heritable characteristics are passed down from
generation to generation.
• These include: structural and distinguishing traits such as
eye colour, hair type, skin colour and ear lobes.
• Non-Heritable characteristics are acquired by each
individual separately and not necessarily passed on from
generation to generation.
• These can include athleticism, artistic ability, having big
muscles, dyed hair
Discrete vs. Continuous Variation
• Discrete variation are characteristics that only has a few
choices, either/or
• Example: being able to roll your tongue or not; albino or
not
• Continuous variation are differences that have a range of
forms
• Example: height, weight, hair, eye colour
Variations and the Environment
• Some variations may be influenced by interactions with
the environment. These variations are NOT inherited
• Example: Height and weight. How is this influenced by the
environment?
• Example: Changes in pigmentation of skin colour
throughout different seasons
Review
• A scientist wants to study continuous variation in a mouse
population. What mouse characteristics would she/he
investigate?
• Is this discrete or Continuous?
Left Thumb Top Right Thumb Top
4.2 Selecting Desirable Traits
• https://www.youtube.com/watch?v=uLaaVwLseY0
Outcomes
• Identify issues related to selective breeding in game
farming and in the rearing of fish stocks
• Describe newly emerging technologies for recombining
genetic material; and identify issues related to their
application
• Describe the use of biotechnology in environmental,
agricultural, or forest management. Identify potential
impacts and issues
Artificial Selection
• The process of selecting and breeding individuals with
desirable traits to produce offspring that have these
desirable traits
• What is the difference between artificial selection and
natural selection?
• Natural selection – Nature selects for traits (predator prey
relationships)
• Artificial selection – traits are chosen for (vegetables)
Artificial Selection
• Artificial Selection can be applied to animals, food and
ornamental plants.
• Since the beginning of farming humans have practiced
artificial selection.
• Example: Corn
Risks in Animals
• Artificial selection can reduce genetic variation by creating
many offspring of the same individual animals
• Having many animals that are genetically identical are
more likely to get diseases that genetically differing herds
of animals
Risks in Plants
• Many of our crops were produced by artificial selection of
wild plants
• There has also been genetic engineering done to the
crops to try and make them resistant to herbicide so that
the crops can be sprayed and only the weeds die
• Many crop plants can still cross with their wild weed
relatives and some weeds can become resistant to
herbicides
Biotechnology
• Biotechnology is using living things to make agricultural,
industrial or medicinal products.
• Farmers and ranchers began using biotechnology many
years ago to improve their crops and herds.
• How would they do this?
• It takes many generations to successfully get an organism
with desired traits
Creating Plant Clones
• Originally horticulturalists “cloned” a plant by taking a
cutting off of it and growing an identical version of it
• Today scientists can clone faster by taking a cell from an
individual plant with desirable traits and place it in a Petri
dish where they can grow into seedlings
• Many more seedlings can be grown through cloning a cell
than through cuttings
Artificial Reproductive Technology
• Artificial Reproductive Technology is any artificial method
of joining a male and female gamete
• Most cows in Canada are produced this way
• Artificial insemination us when sperm are taken from a
bull with the desired traits and the sperm is inserted into
the female cow
• What is the benefit of artificial insemination?
Genetic Engineering
• Refers to any technology that directly alters the DNA of an
organism
• This usually consists of inserting a desirable gene from
one species into another
• Example: Some genetically modified bacteria now
produce insulin because of a gene inserted into them
• Diabetics need insulin and since bacteria grow so quickly
they can produce a lot of insulin which allows it to be sold
cheaply
Biotechnology and Society
• Development of technology that allows us to select or
introduce desirable traits of the organism around us have
given humans some important benefits
• However we need to use these technologies responsibly
and be aware of the possible risks as well as the benefits
Cloning
• Scientists are able to produce an identical copy of a single
animal
• The most famous example is a sheep named Dolly who is
genetically identical to her mother
• Dolly was made from a full-grown mother
• Even though Dolly is 6 years younger than her mother her
cells appear the same as her mothers
Cloning
• Cloning is still in its early stages
• Many have reported unsuccessful pregnancies, birth
defects, and deaths among clones.
Dolly the Sheep
Case Study
• Work in your Table Groups and read through the study.
• Create a Pro/Con list to answer the question at the end of
the study.