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

-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 ADAPTto increase their chances of survival

-Some adaptations are STRUCTURALADAPTATIONS

–Ex. Gills to get oxygen

-Some adaptations are BEHAVIOURALADAPTATIONS

– 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

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 diversityindex, 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.

  1. If the second organism is the same as the first,

assign it the same letter ex. A, A

  1. If the third organism is different than the first and

second assign it the letter “B” ex. A, A, B

  1. 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

  1. 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

- 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

-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)

GENERALISTScan 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

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

- 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

-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

  1. 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

Assignment:

Describe the following terms:

SpecialistMetamorphosis

NicheSpecies

Diversity indexAbiotic

Structural adaptationsVariations

Biological diversityCommensalism

PolymorphismBudding

PopulationMutualism

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

-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

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

Lesson 5: Genetics

- Geneticsis 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

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 blue eyes

tongue roller non tongue roller

dimples no dimples

detached earlobesattached earlobes

widows peak no widows peak

middigital hair 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

Assignment #5:

p. 25 – key terms

p. 25 #2, 5

p. 36 #1 (copy question)

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.

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 furBlack fur - B

Mother – pure bred white furWhite fur - b

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 MUTAGENScan 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

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 – adenineG – guanine

T – thymineC – 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.

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

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 produces 4 eggs each with 1 “X”

- XY – male produces 4 sperm 2 “X” and 2 “Y”

- Therefore it is the male that determines the sex of the child (50/50 chance)

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

- 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?)

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

- They can decide to only implant female embryos if they are trying to increase their dairy cattle