Transcript Biological Diversity - qatarcanadianschool

Biological Diversity
A Brief Unit Review
Topic 1 – Biological Diversity and
Survival
• Biological Diversity refers to the number and
variety of organisms.
• All species rely on and benefit from a high
biological diversity on Earth.
• Variety refers to differences within or between
species.
– There is large variety within the domestic dog specie
– There is large variety among difference species of the
great apes.
Topic 1 - Topic 1 – Biological
Diversity and Survival
• Variety can lead to one species evolving into a
new species. This is called speciation.
• Some variations help us survive. These then
become adaptations:
– Structural adaptations
– Behaviour adaptations
• A Diversity Index compares the diversity of
species in an area with the total number of
organisms in the same area. If many different
kinds of organisms living in an ecosystem would
be indicated by a high diversity index.
Topic 2 – Habitat and Lifestyle
• Species compete for resources when they
become scarce: food, water, sunlight, mates,
etc.
• Often, the better adapted species wins.
• Generalists have many adaptations that allow
them to occupy broad niches and often reduce
competition for resources.
• Specialists are only adapted to one type of
environment (or they have a narrow niche) and
often compete with one another and with other
species.
Topic 2 – Habitat and Lifestyle
• Many different species rely on symbiotic
relationships for survival:
– Mutualism:  and 
– Parasitism:  and 
– Commensalism:  and :l
Topic 3 – Passing it On
• Reproduction allows us to pass on heritable
traits.
• Asexual reproduction (aka vegetative growth):
– One parent only.
– Offspring are identical to the parent.
– It’s fast and energy efficient but results in little
variation.
– Examples:
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Binary fission
Asexual spores
Budding
Layering
Meristems
Topic 3 – Passing it On
• Sexual Reproduction
– Two parents pass on their genes
– Takes more time/energy but results in
variation.
– Gamete  Zygote  Embryo  Multicell
organism
– Flowering and cones plants do it! (see p. 33)
– Bacterial Conjugation is considered a form of
sexual reproduction because two different
bacterial cells are sharing their genes
Topic 4 – Wearing Your Genes
• Genetic traits can have discreet variation (there
are only a few different possibilities – ex: eye
colour) or continuous variation (there is a wide
range of possibilities – ex: height)
• Genetic traits can also be influenced by
environmental factors (ex. Diet).
• Genes can also mutate
• Each of our genes are made up of two alleles
(one from mom, one from dad).
Topic 4- Wearing Your Genes
• Some alleles are dominant over other
alleles (recessive). These dominant traits
are the ones that are expressed.
• Fred Flinstone can roll his tongue (Tt) and
Wilma cannot (tt), what is the probability
that Pebbles can roll her tongue?
Topic 5 – When Plans Change
• All of our genes can be found within DNA
(deoxyribonucleic acid).
• DNA is a double helix (a twisted ladder)
– The sides are made of alternating sugars &
phosphates
– The rungs are made of paired nitrogen bases
• Adenine (A) pairs with Tymine (T)
• Cytosine (C) pairs with Guanine (G)
– A nucleotide = sugar + phosphate + nitrogen base
• DNA folds itself into chromosomes
Topic 5 – When Plans Change
• A human has 23 pairs of chromosomes (46
chromosomes: 23 from mom + 23 from dad).
• Mitosis:
– Body Cell (46)  Doubles (92)  2 body cells (46
each)
• Meiosis:
– Sex cell (46) Doubles (92)  2 sex cells (46 each)
 Divides: 4 gametes (23 each)
• Reproduction
– Sperm (23) + Egg (23) = Zygote (46)  Embryo (46)
 Baby (46)
Topic 5 – When Plans Change
• Biotechnologies, like genetic engineering, occur
when humans change/use genes.
• Agriculture benefits from genetic engineering by
creating genetically modified foods.
– This technology has led to a reduction in biodiversity
of naturally occurring fruit and vegetable plants.
• Medicine benefits also. We can place the
human gene responsible for creating insulin into
pigs, bacteria, and plants, and have them
produce human insulin for us!
Topic 6 – The Best Selection
• Artificial Selection is when humans breed
organisms with desirable traits. Aka
Selective Breeding.
• Natural Selection occurs when the most fit
species survive, reproduce, and produce
offspring that are genetically more fit for
survival (survival of the fittest)
Topic 6 – The Best Selection
• The Theory of Natural Selection:
– All organisms produce more offspring that can
possibly survive
– There is incredible variation within each species.
– Some of these variations increase the chances of an
organism to survive to reproduce.
– Over time, variations that are passed on lead to
changes in the genetic characteristics of a species.
Topic 7 & 8 – The Sixth Extinction
• Some say we are experiencing the 6th
major extinction on Earth because
biological diversity is decreasing at an
alarming rate.
• Humans activities are causing these
extinctions.
Topic 7 & 8 – The Sixth Extinction
• We can preserve biological diversity by:
– Zoos and Aquariums
• Education
• Breeding – organisms are exchanged between
zoos to prevent interbreeding.
– Seed Banks
– National Parks
– International Treaties
• CITES (Convention on International Trade of
Endangered Species)