Welcome to Science 3/9/2012 Answer the Question of the Day that is on your

paper. Circle the correct answer.Today’s Schedule

1. Pass back & review lab test 2. Experiment of the Day3. Question of the Day4. Review Asexual Reproduction5. Sexual Reproduction6. Mitosis v. Meiosis Activity

Question of the Day• Hunter found some termites in a wooden board sitting

in his backyard, so he sprayed some insecticide on the board to kill the termites. Hunter noticed that about 95% of the termites died, but 5% survived. What is the most likely explanation for this?

A. The living termites had genes that the dead termites did not have.

B. The living termites knew that Hunter was going to spray the insecticide, so they camouflaged themselves.

C. The living termites were a different species than the dead termites.

D. The living termites were males and the dead termites were females.

Asexual Reproduction Review

• What is asexual reproduction?

• One parent produces two new, genetically identical organisms.

Asexual Reproduction Review

• What are some organisms that can reproduce asexually?

• Plants, simple organisms, and some complex organisms.

Asexual Reproduction Review

• What are the types of asexual reproduction?

• Binary fission, budding, regeneration, and parthenogenesis

The Big Picture

• Asexual reproduction limits the spread of different characteristics through a species and only allows for genetic continuity.

• This can be good or bad for the organism. It all depends on the environment.

• Sit with your lab group and get out your sexual reproduction notes that we began on Friday.

• Today’s Schedule

• 1. Schedule for the week

• 2. Question of the Day

• 3. Review Sexual Reproduction

• 4.. Mitosis v. Meiosis Lab

Question of the Day• Both paramecia and fish live in a shallow pond. The

paramecia usually reproduce asexually. The fish reproduce sexually. Suppose the environmental conditions in the lagoon change. What advantage will the sexually reproducing fish have?

• A. sexual reproduction decreases the genetic variability in the fish populations.

• B. Sexually reproducing fish produce offspring that are identical to the parents.

• C. Sexual reproduction limits the spread of harmful characteristics in fish populations.

• D. Sexual reproduction in fish allows populations to adapt to new conditions over fewer generations.

Video of the DayVideo -- Bighorn Sheep Competition -- National Geographic

Sexual Reproduction• How is sexual reproduction different than

asexual reproduction?

• Sexual reproduction produces a new organism when sex cells from two parents combine to make a new organism.

Production of Cells• A human body cell has 46 total chromosomes. • Chromosomes- parts of a cell that store the

hereditary information that is passed on

How do we get new cells?• Cells are alive. Therefore, cells have a life cycle

• Mitosis (cell division)- process by which a cell nucleus divides to form two identical cells

• Animation: Mitosis

How do organisms produce sex cells?• Remember, a human body cell has 46 total

chromosomes. • How many chromosomes would there be when two

human sex cells combine?• List of organisms by chromosome count

Human sex cells can only have 23 total chromosomes.

How do we produce sex cells?• Meiosis- the process of cellular division that

produces sex cells.• Meiosis happens in the reproductive organs of

plants and animals. Meiosis: An Interactive Animation

• Animation: How Meiosis Works

Meiosis v. Mitosis

Fertilization• S.R. starts with the formation of sex cells and

ends when one sex cell joins another and a new organism is begun.

• Fertilization- the joining of an egg and sperm

The Big Picture• Sexual Reproduction involves two organisms.

• Each parent organism passes their traits on to the offspring.

• The offspring is born with a combination of traits from its parent.

• This combination of traits will either increase or decrease the offspring's chances of survival.

Mitosis v. Meiosis Lab• 1. On the back of your notes you are going to

create models of the process of mitosis and meiosis.

• 2. First, use your text book to create a sketch of mitosis and meiosis in the correct locations of your paper.

• 3. Second, you will create a 3-D model of mitosis and meiosis using clay.

• 4. In your model, include all of the important details of the cells.

Mitosis v. Meiosis Lab• Everyone will fill in the lab sheet, help in

creating the models, and answer the questions.

• After finishing the lab sheet create a model of all of the following:

• A hydra budding

• A Sea star regenerating a arm

• A bacteria undergoing binary fission