Friday, February 6, 2009

Settling Lab

For students looking for the settling rate lab, please download the file at the following link:

(I'm beyond the age where I can figure out how to attach viruses and bad stuff to hurt your computer. If you hover your mouse over the link, you can see that the URL links you back to the website, so you know it's safe! If not, just go to the school's website, look for my name and click on "announcements.")

Have a good weekend!

Monday, October 27, 2008

Test 2 Review

Cell Division
One “parent” cell divides into two new “daughter” cells. Every parent cell passes along to its daughter cells a set of “operating instructions” necessary for the cells to function properly. The genetic information in the chromosomes also gives the cell, or the organism it belongs to, its individual characteristics, or traits, like size and shape.
Chromosomes are sections of DNA that carry the information necessary to code for certain traits. They are like the instruction manual of the cell.

Asexual reproduction produces offspring that are genetically identical to the parent cell.
Mitosis - one cell divides into two cells. The daughter cells contain the same number of chromosomes as the parent cell.

Sexual reproduction produces offspring that are genetically different from its two parents. Offspring of sexual reproduction receive one half of their genes from each parent.
Meiosis - one cell divides into four cells. The daughter cells contain have the number of chromosomes as the parents cell.
Meiosis produces sex cells (gametes), such as sperm and egg cells.
The joining of a sperm and egg cell is called fertilization.
The product of fertilization is a zygote.
The zygote goes through mitosis and becomes an embryo.

The flower is the reproductive organ of a plant. It contains male and/or female parts.
The pistil is the female part of the plant.
The stamen is the male part of the plant. It contains the anther. The anther produces pollen, which are the sperm cells of a plant.
In a plant, the fertilized ovary turns into the fruit of the plant. The fruit usually contains seeds. Seeds protect the embryo of a plant.

Metamorphosis is a big change from one stage of growth to another. For example, eggs hatch into caterpillars (larva), which form a chrysalis (pupa), and emerge as a butterfly (adult).
Egg --> larva --> pupa --> adult
Incomplete metamorphosis skips the pupa stage. The nymph looks a lot like the adult, except it usually does not have wings.
Egg --> nymph --> adult

At least two genes code for each trait. One gene comes from the mother, and one gene comes from the father.
Genes can be either dominant or recessive.
Dominant genes will always show their characteristics, therefore recessive genes will not show through when a dominant gene is present.
An organism that has two of the same genes is called pure, or homozygous. They will have either two dominant genes or two recessive genes.
An organism that has two different genes coding for a trait is called a hybrid, or heterozygous. They have one dominant and one recessive gene.
Punnett Squares are used to solve genetic problems. This is an example of a Punnett Square for one hybrid parent and one pure recessive parent for hair color. B= brown, b=blonde. Brown hair is dominant. The letters in bold represent the parents.

B b

b Bb bb
b Bb bb

This table shows the percentage of offspring that MAY display a trait. For example, the offspring of these parents have a 50% chance of having brown hair (Bb), and a 50% chance for having blonde hair (bb).

Mutations are genetic accidents that create new genetic material in a species. If the change is beneficial to the organism, it will be better able to survive and reproduce, and pass on to the next generation.
Natural Selection favors organisms that are best able to survive and reproduce. After many generations, and many mutations, the organism may look and behave so differently from its ancestors that is has become a new species. This process is called evolution.

Genetic diseases can be caused by mutations. Albinism (a lack of pigment), hemophilia and sickle-cell anemia are examples of genetic diseases. They are usually on recessive genes. Genetic counseling can help couples determine the chance that their children will have the disease, using

Genetic engineering is when humans deliberately breed animals or plants together to get a desired trait. For example, we can breed plants to make them produce more food, or breed dogs to make them bigger. There is some disagreement about the morality of genetic engineering. What do you think about it?

Living organisms are classified into groups. From biggest to smallest, they are: Kingdom, Phylum, Class, Order, Family, Genus, Species.
We use the mneumonic device "King Philip Came Over For Good Soup" to remember this. Make up your own if you're feeling creative!