Download Biodiversity

Unit 1
BIOLOGICAL DIVERSITY
MR. JALBERT
Biological
Diversity:
variety of
species and
ecosystems on
Earth.
Ecosystem
Diversity
Community
and Species
Diversity
Genetic
Diversity
So, what is biodiversity?
 Biodiversity: the number and diversity of living
organisms in a community.
 Purpose?
 Measured using the index of diversity
Some Definitions…
 Species: organisms that are similar in appearance
that can reproduce viable offspring with the same
general characteristics as the parents.
 Variation: differences
within a group of similar
living things. No two
organisms even within
the same group are
exactly alike.
 Differences between
individuals (among/within
species).
 Do you think variation is good or bad?
The English Peppered Moth:
Variation to Adaptation
 The proportion of flecked and black moths in
this population of peppered moths changed in
response to changes in the environment.
 Before Industrial Revolution: Flecked moths
were dominant, Black moths were rare.
 After Industrial Revolution: Black moths were
dominant, Flecked moths were rare.
WHY?
 Before Industrial Revolution:
- Flecked moths were camouflaged (structural adaptation)
in trees (light coloured lichen), the black moths were easily
seen and easily preyed upon.
 After Industrial Revolution:
- Due to air pollution, it killed the lichen thus the flecked
moths were easily seen and eaten by birds, while more
black moths survived long enough to reproduce and pass
on their genes to their offspring.
- The Peppered moth population changed over the course
of several moth generations, and didn’t change from
flecked to black.
 Ecosystem: where living (biotic) things interact
with other biotic and abiotic (non-living) things
 Ecosystem Diversity: communities and
environments where biotic and abiotic things are
found
 Population:
members of a same
species living in a
specific area and
sharing resources
 Community:
populations of
different species
living in the same
area
A Classroom of Differences
 Our class provides and excellent place to investigate
variations or differences within a group of similar
living things.
Instructions:
1) Stretch out your hand. Measure the distance (to the
nearest millimeter) from the tip of the thumb to the
tip of the little finger of your outstretched hand.
2) Come and share the distance with me
3) Create a bar graph indicating the results for our
class.
Follow up Questions:
1) Can you explain the shape of the graphs ?
2) Predict whether the graph would have the same
shape if you measured the hand spans of students
in grade 1 and in university?
3) What are factors that might cause variations
between you and your classmates?
Summary
 Explain why preserving biological diversity is
important to life on Earth?
 Compare and contrast between the meaning of
population and community?
Niche: job or role
 Two types: broad and
narrow
 Broad: large populations,
but little variety
 Found in northern climates
 Organisms are generalists
– can adapt to a wide variety
of environmental conditions
(i.e. eat many plants, adapt
to temperature and season
change)
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Narrow : specific niche, able to live in close
proximity with other organisms.
Large variety, small population
Found around the equator
Organisms are specialists - they could NOT
survive in another environment
Trap of specialization
Adaptation
 Species adjust to
surrounding
conditions.
 Morphological:
physical change.
 Behavioural:
change in behaviour
(immigration, night
hunting)
Relationships
 Symbiosis
 Mutualism: both organisms benefit
 Commensalism: one benefits, the other is
unaffected
 Parasitism: one benefits the other is harmed
Life cycle of a tapeworm.
 Predation is where one organism kills another.
 Interspecies competition: when 2 or more
species compete for the same resources.
 Intraspecies competition: members of the same
species compete for resources.
Variation in Species
 Survival advantage when the environment
changes
 A bacterial population which is exposed to an
antibiotic will be killed. However, there will be
some bacteria which can tolerate the antibiotic due
to variation.
 The peppered moth has a variety of colouring from
very dark to very light. During the industrial
revolution in England, their environmental
conditions changed because the factories emitted
smoke and the soot covered the trees. The light
moths were eaten because they no longer could
adapt to their dark environment. The peppered
moth species continued because the dark ones
survived the environmental change.
Asexual Reproduction
 No union of male and female sex cells
 The transmission of the same genetic information
from a parent to its offspring
 The offspring is an exact copy of the parent.
Types
 Binary Fission: single cell
organisms, genetic
information is copied and the
cell divides into two identical
cells equal in size Ex. bacteria
and amoeba
 Budding: formation of a bud
on an organism which grows
to become a new organism
independent of the parent
(DNA is identical) Ex. hydra
 Spore Production: Production of a hardcoat seed-
like structure by the division of cells in one parent.
 Example: A fern plant produces spores in one part of
its life cycle and then produces sex cells (zygospores)
in the other part of its life cycle.
 Spores grow into multicellular individuals without
fertilization
 Vegetative Reproduction: a new plant can be
formed from the vegetative parts of the parent.
 Example: Runners in strawberries, eyes on the
potatoes, cuttings of plants, bulbs of daffodils and
tulips, suckers from aspen trees.
Sexual Reproduction
 The union of male and female sex cells which
requires two parents.
 Offspring are different because they have
characteristics of both parents.
Types
 Bacterial Conjugation: One bacterium grows a
tube-like structure and passes on a copy of its DNA
to another bacterium.
Plants
 Sperm is found in pollen
 Eggs are found in the ovary
 Seeds are made by the union of sperm cells with
egg cells
 Plants can also reproduce by cuttings, suckers,
runners, and bulbs. Examples: asparagus,
potatoes, spider plant.
 Yeast can reproduce by both budding and sexual
reproduction.
Shmooing – process by which two haploid yeast cells grow
toward each other to fuse and create a diploid cell.
 Angiosperm: flowering plant
 Gymnosperm: plant that produces seeds inside
of cones
 Self-pollination: the sperm and the egg
(gametes) come from the same plant
 Happens generally in smaller , uglier plants
 Cross-pollination: the sperm and egg come
from two different plants
 Happens in more colorful and scented plants. As
well as larger plants.
 The flowers are the
reproductive structures of
the plant
 Pollen contains the male
gametes and is made in the
anther and found on the
stamen
 Pollen/sperm travel to the
pistil, and into the ovule
where it meets the egg,
when sperm and egg fuse a
zygote in formed
Animals
 Two parents whose sex cells
undergo meiosis
 Meiosis results in sperm
production in a male and egg
production in a female
 When the sperm and egg
unite, this is called
fertilization
 As the new organism grows a
zygote is formed and later an
embryo and then a fetus
 Chromosomes are found in the nucleus of cells and carry
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all genetic information
A human body (somatic) cell has 46 chromosomes
A sperm and egg each have 23 chromosomes
When a sperm and egg unite at fertilization, the
chromosome number is restored to 46
Sperm and egg can be called gametes
How many chromosomes are there in a zygote? In an
embryo?
http://www.youtube.com/watch?v=QnnTSvATOpc&featur
e=related
Fertilization in Animals
 Fertilization: sperm and egg
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fuse to form a zygote
Need a liquid environment
for the sex cells because
they are delicate and can
dry out easily
Can be internal or external
External: fish, sponges,
amphibians
Risky: zygote could be
eaten, washed away,
subjected to cold/heat,
pollutants etc.
 Internal:
humans, birds,
whales, insects,
reptiles
 High rate of
success because
the embryo is
protected from
the climate and
predators.
http://www.youtube.com/watch?v=J_knnENhzwg
Variation
 Two types: discrete
and continuous
 Discreet variation: a
trait that has only a few
physical expressions
with limited ways of
showing the trait
 Examples…
 Continuous
variation a
trait that has a
range of
expressions.
 Examples…
Characteristics can be
 the same as both parents
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Racial features such as single or double folded eyelids
the same as one parent
Being male or female.
intermediate between parents
Eye colour, height, weight, hand span, feet size
Different from both parents
Snapdragons can be red, white or pink
Mendel and the Pea Plants
 Gregor Mendel studied how characteristics were
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passed down from parents to offspring using pea
plants
Recessive: a trait that is masked or not shown
Dominant: a trait that is expressed or shown
When mixed with dominant traits, the recessive trait
does not show up.
He used punnett squares to predict offspring
 Pea plants can be tall or short, yellow or green etc.
 A punnett square shows the chance of 2 parents
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having a certain type of offspring ie. tall or short
Definitions
Heterozygous: both a dominant and recessive allele
for the trait
Homozygous dominant: 2 dominant alleles for the
trait
Homozygous recessive: 2 recessive alleles for a trait
Heritability
 Heritable traits can be passed on from parent to
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offspring
Examples…
Non-heritable traits cannot be passed to offspring
Examples…
An organism is affected by the genetic make-up
received from parents and the environment
Purebred: a plant or animal whose ancestors all
with the same form of a trait.
Hybrid: an organism created by crossing two
purebred parents.
 Allele: variation of
a gene. Ex: White,
red, pink are colours
are variations for
pigment in snap
dragons.
 Cell – NucleusDNA- Chromosome
– Gene – Allelle
 http://learn.genetics
.utah.edu/content/b
egin/tour/
Molecules
 DNA : stores genetic
information for heritable
traits in all living organisms
and directs the structures
and functions of the cell.
 Chromosome: tightly
packed strands of DNA in a
cell visible under a
microscope during cell
division.
 Gene: a section of DNA on a
chromosome that codes for a
specific protein and function.
Structure of DNA
 Double helix, twisted rope, coiled ladder.
 The sides are made of alternating units of sugar and
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phosphate. The rungs are pairs of nitrogen bases:
Adenine always pairs with Thymine.
Cytosine always bonds with Guanine.
Genetic Code: The sequences of nitrogen bases in a
DNA molecule makes up a code.
http://www.youtube.com/watch?v=qy8dk5iS1f0
Meiosis
 Cell reproduction where the original number of
chromosomes is divided in half in the daughter cells.
 Produces sex cells (sperm, egg).
 In humans sex cell production begins with a cell that
has 46 chromosomes (diploid) and ends with 4 cells
that each have 23 chromosomes (haploid).
Mitosis and Binary Fission
 Cell reproduction where chromosomes are
duplicated into 2 daughter cells
 Each daughter cell has the same number of
chromosomes as the original parent.
 For somatic or body cells (muscle, nerve, skin,
hair etc.)
 In humans we begin with one cell with 46
chromosomes and we end with two cells with
46 chromosomes.
Sexual Reproduction
 Advantages: traits mix which = variation.
 Disadvantages: not be as efficient, right conditions,
takes lots of energy and time, produces a limited
number of offspring.
Asexual Reproduction
 Advantages: no specialized cells are needed or a way
of bringing the sex cells together, makes a lot of
individuals quickly.
 Disadvantages: makes copies which = no variation.
Darwin’s Theory of Natural Selection
 Survival of the fittest!
 All organisms produce more
offspring than can survive.
 Variation within each species.
 Some variations increase the
chances of an organism
surviving to reproduce.
 Over time, variations that are
passed on lead to changes in
the genetic characteristics of a
species.
 http://science.discovery.com/interactive
s/literacy/darwin/darwin.html
Charles Darwin
 Natural Selection:
Nature decides which
organisms survives to
reproduce and pass on
their traits to the
offspring.
 Ex: Those which resist
disease, famine,
environmental disasters
 http://biologyinmotion.c
om/evol/index.html
 Artificial
Selection: Man
decides which
traits will be
passed on to
offspring (selective
breeding).
 Ex: Pears, apples,
dogs, cats, dairy
cows, wheat.
Cloning
 Complete set of DNA is taken out of cell of an
organism and inserted into an enucleated egg cell
(egg DNA removed)
 Result: an embryo that is an identical copy of the
original parent
 Dolly the sheep
http://gslc.genetics.utah.edu/units/cloning/c
lickandclone/
Genetic Engineering
 Remove a gene from the DNA of a cell
 Insert a new section of DNA
 DNA must have the same complementary ends
 Scientists use enzymes to cut sections of DNA.
 Examples: Firefly gene inserted into a tobacco plant,
a goat that milks silk, bacteria producing human
insulin
Artificial Reproductive Technologies
 Surrogacy
 Artificial insemination: sperm is harvested from a
male and inserted into a female
 In vitro fertilization: sperm and egg are harvested
from organisms and fertilized in a Petri dish
 http://www.sumanasinc.com/webcontent/anisamples/biology/biology.html
Abundance of Species on Earth
 Insects are the most
numerous species on Earth.
 Insect diversity is greater in
tropical climates than at
the temperate zones.
 One hectare of rainforest
may have over eighteen
thousand species of beetles
whereas in all of Canada
and United States there are
only twenty four thousand
species of beetles.
 Extinction is the
disappearance of every
individual of a species from
the entire planet.
 Extirpation is the
disappearance of a species
from a particular area.
Natural Causes of Extinction
 Catastrophic events
like volcanoes,
floods, fire
 Lack of food due to
overpopulation
 Disease
 Overspecialization in
a single niche
Human Causes
 Habitat destruction
 Introduction of non-native species
 Over-hunting
In Situ Conservation
 Maintenance of wild populations in their
functioning ecosystems.
 The creation of protected areas from national,
provincial, and municipal governments which
allow organisms to live undisturbed in their
natural habitat.
 Restoring ecosystems and species – setting up
programs to reintroduce species into their natural
habitats.
Ex-Situ Conservation
 Breeding endangered
populations in zoos.
 Development of seed banks –
keep a record/sample of all of
the species of plants, may
include storage of a particular
type.
 Treaties to protect endangered
species.