Unit 1 -
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 _____________.
The number and variety of organisms in an ecosystem is called BIOLOGICAL
_____________________.
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
When members of a species live in a specific area and share the same
resources they form a __________________.
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
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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 ____________ may develop within a species.
This results in the formation of a new species
Over several generations, organisms will ____________ to increase their
chances of survival
- Some adaptations are STRUCTURAL ADAPTATIONS
– ex. Gills to get oxygen
- Some adaptations are BEHAVIOURAL ADAPTATIONS
– 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.
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Lesson 2 - DIVERSITY INDEX
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 ______________ ____________, 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. Starting with “A” assign each organism that you see a letter.
2. If the second organism is the same as the first, assign it
the same letter ex. A, A
3. If the third organism is different than the first and second assign it
the letter “B” ex. A, A, B
4. Every time you come across an organism that is different from
the last one, assign it a new letter.
5. Each change starts a new “RUN” of data
5. Determine the number of runs, by counting how many different
letters you used.
7. 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
Diversity Index = 4/9 = 0.44
The Niche
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- 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 ____________ .
- 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
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 _____________ .
Competition occurs when there are limited ____________, 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 ______________ .
(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 _______________ within or between species.
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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.
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:
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1.
Asexual Reproduction
- Involves only one parent
- All offspring are _______________ 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
Ex. Yeast, hydra
d) Vegetative Reproduction
- Growing tips of roots and stems contain areas of rapidly reproducing
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cells called MERISTEM
- Can take a cutting of a plant, and the meristematic cells will produce a
new plant that is a ______________ 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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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 _________, when the new recombined
genetic material is passed along
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 ______________ to prevent drying and gives the sperm a
fluid to swim through to reach egg
- Animals such as clams and sponges use external fertilization.
- 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 _______________ .
- 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 _______________ .
- 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
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
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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 ____________ and one recessive allele for a trait
Lesson 6: Factors Affecting Genetic Information
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- 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 ________________ .
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 ______________
- Inside the cell is the nucleus, which contains DNA.
- DNA is the material responsible for ________________ 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 ___________________.
- 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 _________________ 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 ________________ 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.
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
- 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)
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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 ______________ 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 _______________ 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
- 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
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- 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 _______________ .
- 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?)
Lesson 9: Artificial Selection
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- 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 _________________ .
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
- 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”
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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.
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 ________________ .
- Degradation of these ecosystems has resulted in extinction of
different species.
Extinction – the disappearance of every individual of a species from the
entire plant
- 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 ________________ 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
- 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
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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
- Civilization and urbanization have resulted in the loss of various habitats
- Air ______________ has created problems such as global warming
- Changes in temperature may result in ____________ 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 _______________ .
- 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 10: Preservation
- Zoos are part of a worldwide network attempting to protect and
preserve endangered animals
- Animals are exchanged between zoos to maintain genetic diversity
of the species
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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
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