Biological Diversity and Survival
Lesson 1:
Diversity and Species
- An ecosystem is any place on Earth in which
living (biotic) things interact with other living things and
non-living (abiotic) things
Ex. Marshes, lakes, forests, desert, arctic
- Organisms have different characteristics or VARIATIONS.
- The number and variety of organisms in an ecosystem is
called BIOLOGICAL DIVERSITY.
- Each organism plays a role in the food chain and within the
ecosystem
ex. Mosquitoes, although they are annoying and can transport
diseases, they are food for dragonflies, etc.
SPECIES: the smallest group in which all organisms have a
very similar set of characteristics
Biologists also define species as a group of organisms that
interbreed in nature, and whose offspring are able to breed.
Ex. Lions and tigers are able to interbreed in zoos, but their
offspring are sterile. Therefore they are different species. They
do not interbreed in nature since they live in different habitats
Offspring are called:
Ligers – if father is a lion and mother is a tiger
Tigons – if father is a tiger and mother is a lion
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When members of a species live in a specific area and share
the same resources they form a POPULATION.
- When populations of different species live in the same area,
they form a COMMUNITY.
-
Diversity within Species
- in some species, the young are much different looking than the
adults: change is called METAMORPHOSIS.
ex. Tadpole – frog, grub-beetle, caterpillar- butterfly
- In some species, the males look different than the females:
SEXUAL DIMORPHISM.
ex. Humans, peacocks
- in some species, there are several different looking forms:
POLYMORPHISM
ex. Ants: queen, worker, soldier
Bees: queen, drone,
SPECIATION: - over time a new characteristic may develop
within a species. This results in the formation of a new species
- Over several generations, organisms will ADAPT to increase
their chances of survival
- Some adaptations are STRUCTURAL ADAPTATIONS
– Ex. Gills to get oxygen
- Some adaptations are BEHAVIOURAL ADAPTATIONS
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– Ex. Nocturnal organisms; migration
- Variation within species is important so that entire populations,
communities, and ecosystems are not wiped out by a single
catastrophe.
- For example a disease may destroy one species of tree, but the
others will remain unharmed.
Lesson 2 - DIVERSITY INDEX
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Compares the diversity of species in an area with the total
number of organisms in the same area. The closer to “1” the
greater the diversity.
Tropical areas tend to have a higher diversity index, since there
is more water, a greater variety of food, etc.
ex. Mexico – 293 different species of snakes
United States – 126 species of snakes
Canada – 22 species of snakes
Over population, pollution, hunting, etc. may result in a lower
diversity index
How to Calculate the Diversity Index
1.
2.
3.
4.
5.
5.
7.
Starting with “A” assign each organism that you
see a letter.
If the second organism is the same as the first,
assign it the same letter ex. A, A
If the third organism is different than the first and
second assign it the letter “B” ex. A, A, B
Every time you come across an organism that is
different from the last one, assign it a new letter.
Each change starts a new “RUN” of data
Determine the number of runs, by counting how
many different letters you used.
Count the total number of specimens in your trial.
Diversity Index = Number of Runs
Number of Specimens
e.g. A,A,A,B,C,C,C,C,D
4
Diversity Index = 4/9 = 0.44
The Niche
- The term niche describes the role of an organism within the
ecosystem
- An organism’s niche includes 2 parts - where it lives and what it
does
- Adaptations allow an organism to play a specific role in its
environment
- ex.
Producers - produce own food usually through
photosynthesis
Herbivores -eats only producers
Carnivores - eats only consumers
Omnivores - eat producers and consumers
Decomposers - breakdown dead organisms an organic
material; release nutrients
- Organisms that live in the tropics, where there is lots of food
and stable temperatures, are SPECIALISTS and have a
NARROW NICHE
- They are well suited to one particular environment
- This allows a number of different species to inhabit the same
area, but prevents them from moving to new areas
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- Organisms that are able to survive in the harsher Canadian
climate in general have a BROAD NICHE (they have
adaptations that allow them to survive the wide range of
temperatures)
GENERALISTS can live almost anywhere
When introduced into a new area where there are too few
predators, generalists spread rapidly often taking over, and forcing
out the indigenous species
Competition occurs when there are limited resources,
and more than one organism needs the same resource
- Can occur between members of the same species or
between different species
- Variations between individuals may give one of them an
advantage (better chance for survival)
- The less successful species may have to change its
habitat or use a different food source
- As organisms change to avoid or reduce competition they
alter their niches
- This increases the variation within or between species
Symbiotic Relationships
- When 2 organisms live in direct contact - there are three types
(a) Mutualism – BOTH partners benefit
(b) Commensalism – ONE partner benefits, and the other neither
benefits nor loses
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ex. A bird builds a nest in a tree.
(c) Parasitism – One partner benefits and the other is harmed
ex. A tapeworm attached to the intestinal wall of a human,
robbing the human of nourishment. They do not kill their hosts
because the hosts represent their food supply
Lesson 3:
Reproduction
Two types:
1.
Asexual Reproduction
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- Involves only one parent
- All offspring are identical to the parent
- Common among bacteria and fungi
Advantages: No need to mate
Occurs quite rapidly
No specialized cells required
Disadvantages: all cells are exactly the same; anything that kills
one will kill them all
Types of asexual reproduction:
a) Binary Fission
– Cell duplicates its contents and then splits in half
- Only occurs in one-celled organisms like amoeba, bacteria, and
some algae
b) Asexual Spores
- Similar to seeds, but are produced by the division of cells on the
parent
- Many spores are produced to ensure survival of some
- ex. Mushrooms, green algae, ferns
c) Budding
- parent produces a small bud, or smaller version of itself
- the bud eventually detaches and becomes a new individual
identical to its parent
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- ex. Yeast, hydra
d) Vegetative Reproduction
- Growing tips of roots and stems contain areas of rapidly
reproducing cells called MERISTEM
- Can take a cutting of a plant, and the meristematic cells will
produce a new plant that is a CLONE of the parent
- Strawberries and spider plants send out runners that produce
new plants along them - Suckers from trees
2. Sexual Reproduction
- Requires 2 parents
- Genetic material supplied by both parents, therefore the offspring
are not exactly like either one
- Fertilization occurs when an egg (female gamete) unites with the
sperm (male gamete)
- Produces a cell containing genetic material from both called a
ZYGOTE
Advantage: increases the variation in the species, which helps
the species survive environmental changes
Disadvantage: takes longer and requires 2 organisms
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Assignment:
Describe the following terms:
Specialist
Niche
Diversity index
Structural adaptations
Biological diversity
Polymorphism
Population
Metamorphosis
Species
Abiotic
Variations
Commensalism
Budding
Mutualism
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Lesson 4 - Sexual Reproduction in Plants
- Angiosperms (flowering plants) and Gymnosperms (coniferous
trees) reproduce by producing seeds.
PISTIL- female reproductive organ
-is made of the stigma, style and ovary
OVULE – contains the egg, and is found in the ovary
at the base of the pistil
STAMEN – male reproductive organ
- is made of the anther and filament
POLLEN – each pollen grain contains a sperm nucleus that was
produced on the ANTHER of the stamen
POLLEN TUBE – the pollen grows an extension that grows into
the pistil until it reaches the ovule
EMBRYO – the zygote undergoes cell division to produce a
multicellular embryo
COTYLEDONS – supply food to the embryo
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-Some organisms are capable of both sexual and asexual
reproduction
ex. Grass
Bacteria Conjunction
- Bacteria are able to transfer genetic material directly from one
cell to another
- Primitive form of sexual reproduction since 2 parent cells are
required
- Results in genetic recombination but not reproduction, since
there is no increase in number of cells
- This process is followed by binary fission, when the new
recombined genetic material is passed along
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Sexual Reproduction in Animals
- Both male and female gametes must arrive at the same place at
the same time for fertilization to occur
- The zygote requires specific conditions to develop
- Requires a liquid environment to prevent drying and gives the
sperm a fluid to swim through to reach egg
- Animals such as clams and sponges use external fertilization.
Therefore live in water
- Mammals carry out internal fertilization
- In most mammals the embryo develops close to or within the
female
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Lesson 5:
Genetics
- Genetics is the study of heredity
- Non-heritable characteristics are acquired/learned. ex. Piano
playing, language
- Heritable characteristics are passed on from generation to
generation ex. Eye color, hair type, skin color
- Variations in traits can be either
(a) Continuous
– Differences that have a range of forms
ex. Skin color, height, hair color, hand size
(b) Discrete
- Differences in characteristics have a limited number of
possibilities
- ex. Tongue rolling, sex, blood type, hand clasping
- GENES control these inherited characteristics or TRAITS
- Each gamete contains thousands of GENES
- For each trait there are at least 2 genes: one from the mother
and one from the father
- Any gene that affects the same trait is called an ALLELE
- One type of allele is usually DOMINANT, and the other type is
RECESSIVE.
- The dominant one will hide the effects of the recessive
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ex. If brown fur is dominant to white fur and a mouse has one
gene for brown and one for white, it will have all brown fur
- Recessive genes may show up in later generations
ex. 2 brown mice may have white mice
- The frequency of a trait does not indicate it if is dominant
- The frequency of a trait can vary from population to population
Examples of dominant and recessive traits
Dominant
Recessive
brown eyes
tongue roller
dimples
detached earlobes
widows peak
middigital hair
blue eyes
non tongue roller
no dimples
attached earlobes
no widows peak
no hair
Pure Breed - if both alleles for a trait are the same (both dominant
and both recessive)
Hybrid – if they have one dominant and one recessive allele for a
trait
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Assignment #5:
p. 25 – key terms
p. 25 #2, 5
p. 36 #1 (copy question)
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Punnett Square – used to predict the appearance of offspring
- we use a capital letter for the dominant gene and a lower case
letter for the recessive gene
Ex. Brown mouse gene – B
Albino mouse gene – b
Father - Pure Breed Brown (BB)
Mother - Hybrid Brown (Bb)
-each parent passes on one gene for colour
Father
Mother
B
B
B
BB
BB
b
Bb
Bb
Off Spring –
50% pure bred brown
50 % hybrid Brown
Construct a Punnett Square for a hybrid brown father and a hybrid
brown mother. Indicate the percentage of each type of offspring.
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Activity: Observing Human Characteristics (Page 38)
Homework: Vocabulary Review; Topic 1-3
Construct a Punnett square for the following trait in cats and
indicate the % of each type of offspring
Father – pure bred black fur
Black fur - B
Mother – pure bred white fur
White fur - b
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Lesson 6: Factors Affecting Genetic Information
- Some characteristics depend entirely on genetic information that
is passed along to the offspring – nature.
Ex. eye color
- Some characteristics depend entirely on the environment –
nurture.
Ex. Scars, makeup
- Some characteristics are combinations of genetic and
environmental factors
Ex. Weight, ability to hear notes, height of plants,
- Genetic information can be changed by factors in the
environment and by random errors
-These changes to the genetic material are called MUTATIONS
X-rays, U.V. Rays, Cosmic rays and some
chemicals called MUTAGENS can cause mutations
Ex. Cancer cells are mutated cells, which can interfere with
nearby cells and prevent the body from performing normally
Cancer cells go through rapid cell divisions and do not
develop in the same way
- If mutations occur in the gametes, the changes may be passed
on to the child
- These changes in the genetic material increase the variation
within a species
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Lesson 7: DNA (DeoxyriboNucleic Acid)
- All living things are made up of cells
- Inside the cell is the nucleus, which contains DNA.
- DNA is the material responsible for inheritance of different traits
- DNA has the shape of a coiled ladder (see p. 47)
- The sides of the ladder are made of smaller molecules called
sugars and phosphates
- The rungs of the ladder are pairs of nitrogen bases (nucleotides)
A – adenine
T – thymine
G – guanine
C – cytosine
- The arrangement of these 4 chemicals forms a code that
cells can read just like the 26 letters of the alphabet can be
arranged to form words that we can read
- This GENETIC CODE is like a blue print that controls the
production of proteins in the cell
- CHROMOSOMES are tightly coiled strands of DNA
- Each cell must have a complete set of chromosomes in order to
have all the genetic information needed
-Each human cell nucleus contains 23 pair (46) of chromosomes.
- A section of the DNA molecule that codes for a specific protein
and function is called a GENE.
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Mitosis (Cell Division)
– In order for an organism to grow and repair or replace tissues,
the cells must divide. Cell division is also called mitosis.
- Body cells are called SOMATIC CELLS.
- Human body cells have different life spans
- Brain cells last 30 – 50 years
- Skin cells only last 20 days
- Before division can occur the chromosomes containing the
genetic material must duplicate (make a copy of itself)
- When the cell divides, each half gets a complete set of
chromosomes. The 2 new cells are genetically identical to each
other and to the original cell
http://www.edumedia-sciences.com/a70_l2-mitosis.html
Meiosis
- Is a type of cell division that produces cells with only HALF of the
DNA of a normal cell.
- These cells produced are called GAMETES - sperm and egg
cells.
- When a sperm cell (23 chromosomes) fertilizes an egg cell (23
chromosomes) the resulting ZYGOTE has 23 pair (46)
chromosomes
- In humans it is the 23rd pair of chromosomes that determines the
sex of the child
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- XX – female
- XY – male
produces 4 eggs each with 1 “X”
produces 4 sperm 2 “X” and 2 “Y”
- Therefore it is the male that determines the sex of the child
(50/50 chance)
http://www.lewport.wnyric.org/jwanamaker/animations/meiosis.html
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Lesson 8: Genetic Variations
- Asexual reproduction occurs very rapidly, and requires little
energy
- Therefore lots of offspring are produced
- The offspring are genetically the same as the parent
- If conditions become unfavorable, the entire population can be
wiped out
- Sexual reproduction takes longer, and requires more energy
- Fewer offspring are produced
- Offspring have received genetic information from both parents;
therefore there are variations, which increase the chances for
survival
Biotechnology
- Genetic engineering has allowed scientists to move genes from
one organism to another to produce traits that are more desirable,
and increase the chances for survival
- ex. Move the human gene for insulin into bacteria, allowing the
bacteria to produce insulin as a waste product
This allows us to produce insulin in large quantities for diabetics.
- Animals can also be given human genes
- Adding human genes to the fertilized eggs of the animal
produces these TRANSGENIC animals
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- The offspring grow up with the human gene, and are able to
produce human proteins, which can be obtained through the
mammal’s milk
- Aquaculture is used in fish production to add genes for disease
resistance to some varieties of fish
- Growth hormone genes have also been added to fish eggs to
increase the size and growth rate
- Run the risk of transgenic fish escaping into the wild and the
natural fish populations not being able to compete with the
genetically altered fish
- The transgenic fish may grow too quickly for the resources to
support them
- Many crops such as wheat, corn, potatoes etc have been
genetically altered to be tolerant of herbicides
- This allows farmers to spray the crops, killing the weeds but not
the crop
- However, if there is cross-pollination with wild weeds, it can
result in weeds that are resistant to herbicides
- Crops have been engineered to survive different climates
- This means that the same crop can be grown anywhere
- Although new varieties are produced, the widespread use of the
new varieties could result in the elimination of the whole crop by
disease or pests
- Taking a cutting from a plant and growing an identical plant from
the cutting can produce plant clones.
- A faster method is to take cells with the desired traits and grow
them in a petri dish until the cells develop into a seedling and can
be transplanted (What else is needed in the petri dish?)
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Lesson 9: Artificial Selection
- Artificial selection is the process of selecting and breeding
individuals with desirable traits to produce offspring that have
these desired traits
- Many DOMESTIC animals are bred for specific traits
e.g. Breed dairy cows for most milk production
- ARTIFICIAL INSEMINATION is often used to produce offspring
with desired characteristics
- ex. Bulls and cows – more cows can be inseminated
- INVITRO FERTILIZATION involves taking sperm from a prize
bull and eggs from a prize cow and fertilizing the egg in a petri
dish
- Many more embryos are formed
- Each embryo is implanted into a different cow
- Eventually they give birth to many calves, all brothers and sisters
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- They can decide to only implant female embryos if they are trying
to increase their dairy cattle
Selective Breeding in Agriculture
- Taking seeds from the healthiest or best producing plants to sow
the following year
- May want wheat that is high in protein, or matures faster, or more
resistant to cold temperatures, insects or disease.
Natural Selection
- In 1831 Charles Darwin began a 5-year trip on the H.M.S. Beagle
- he stopped at many isolated islands.
- By comparing animals he came up with his theory of Natural
Selection
1. All organisms’ produce more offspring than can possibly
survive
2. There is incredible variation within each species
3. Some of these variations increase the chances of an
organism surviving to reproduce
4. Over time, variations that are passed on lead to changes in
the genetic characteristics of a species
- We say that the environment “selects” which will live
- “Survival of the fittest”
Ex. In a family of rabbits, possibly only one in ten will
survive to reproduce. The one that survives may
have been the fastest or the smartest or the best
camouflaged or the best dodger or some
combinations of all of these.
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The Sixth Extinction?
- There have been 5 major declines in biodiversity in the past
(see p. 66 - graph).
- Areas of plentiful heat, light and rainfall have a greater
abundance of plant life, which leads to more complex food chains
and therefore greater biodiversity
- Degradation of these ecosystems has resulted in extinction of
different species
Extinction – the disappearance of every individual of a species
from the entire planet
- Scientists estimate that 99% of all species that ever existed are
now extinct
- Reduces the number of species on the planet
Extirpation – the extinction of a species in certain locales (areas).
Ex. Grizzly bears from Mexico and most of U.S.
- Reduces biological diversity in an area
- Natural events such as volcanoes, earthquakes, ice age , forest
fires can cause extinction or extirpation
-Lack of food due to overpopulation, disease and
overspecialization have also resulted in extinction
Ex.
Dutch Elm Disease, American Chestnuts (fungus)
Giant Panda – only eats bamboo (can’t switch)
- Most extinctions however are not natural, but a result of human
activity
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- Until the mid 1800’s the world’s population was less than one
billion
- By 1930 the population had doubled and by 1960 it was at 3
billion
Two Main Factors were responsible for this human population
explosion
(a) Improved Sanitary Conditions
- Sewage treatment, water treatment and food handling,
as well as improved medical treatment for diseases increasing
life expectancy
(b) Industrialization
– Rapid production of materials, rapid
transportation and farm mechanizations
Industrialization meant new industries starting
up and people moving near the industries for work resulting in
URBANIZATION (cities).
- Industrialization means more materials are taken from the
environment
- Good farmland is used to build cities
- More natural habitats are being cleared for farmland
- Logging
- Damming of rivers
- More pollution
- Use of pesticides, herbicides, and fertilizers
-Developing nations are often hardest hit by population explosions
- Damage to the rainforests is difficult to repair since forest soil has
few nutrients and prevents re-growth of the forest
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- Civilization and urbanization have resulted in the loss of various
habitats
- Air pollution has created problems such as global warming
- Changes in temperature may result in extinction of specialists
that are unable to adapt to the temperature changes
- The loss of large carnivores, such as bears and wolves is
considered to be a bioindicator.
- These animals are known as bioindicator species.
- Hunting of animals such as the wooly mammoth and the
passenger pigeon have resulted in their extinction
- The loss of one species can result in other species being
endangered since the food chain is affected
- Today greater efforts are made to preserve the natural
habitats and prevent over-hunting and over-fishing
Lesson 12: Preservation
- Zoos are part of a worldwide network attempting to protect and
preserve endangered animals
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- Animals are exchanged between zoos to maintain genetic
diversity of the species
In-situ conservation – maintenance of populations of wild
organisms in their functioning ecosystems
Ex. Banff National Park – established in 1885
-1st national park in Canada - originally only
around the hot springs
- Seed banks – used to gather and store seeds from plants that
are threatened with extinction
- Some are commercial ventures; governments or universities for
research run others
- Stored at –20 °C and a few seeds of each sample are
germinated every ten years
- Global Treaties are established to protect endangered plants
and animals
- 1975 Convention on International Trade of Endangered Species
(CITES) makes it illegal to buy or sell endangered animals or
animal parts
- 500 species were identified for protection
-180 countries have signed the 1992 Convention on Biodiversity
and have agreed to set up protected areas for threatened and
endangered species
- Groups such as Canadian Wildlife Federation and Canadian
Nature Federation educate the people and lobby governments for
more action
Assignment:
p. 78 #1-4
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p. 79 – key terms
Unit 1 Test is on Tuesday, Sept. 30.
Assignment: Unit Review on pages 84 to 87:
#
2, 4, 5, 6, 11, 12(b), 13,
17, 24, 28, 34, 36, 38 (copy questions)
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Lesson 19: Review
Presentation of remaining projects
Review Page 85-87
# 13-18,23,24,28,38,42
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