2.7.11 - blog by Fox

This week:


2/8-Tuesday- going over human evolution (Late arrival! :D)

2/9-Wednsday- review for test


2/10-Thursday- BIO DAY!

2/11-Friday- TEST!!!



Homework:

-19.2 reading due tommorow

Extra credit:

Objectives in the unit packet due day of the test. which is friday.

AGAIN, THE TEST IS THIS FRIDAY.




In class:
-Wrote three definitions in the To Be or Not to Be packet.



TYPES OF EVOLUTION-

Microevolution- Changes that take place within a single species to form variations in populations. These are small changes.

Genetic drift- changes in gene pool of a small population due to chance.






When the beetles reproduce, just by random luck more green genes than brown genes ended up in the offspring. (http://www.evolution.berkeley.edu/)




Macroevolution- Changes that have taken place in a species that leads to two or more different species.






(www.kacr.or.kr) (This is a korean website so I dont know how much of it you understand... if you can understand it... beacuse I don't)




Today we learned about Radioactive dating.

Radioactive dating helps scientists find the approximate age of an object, usualy a fossil.


Radioactevity explanation-


When you go to get an X-Ray, the doctors put a big.. shield-type thing on you to protect you from radioactivity. That shields main objective is to protect your pelvic area where your reproductive parts are, not only your heart and lungs.


The reason for that is if any radioactivity hit your sperm/eggs and caused a mutation, your future child can be born with a strange mutation such as an extra limb. and I dont think anyone would wish that on their children, unless they are some sort of crazy scientists who do that sort of thing. so, thank you, doctors.


The way scientists figure out how old a fossil is is by measuring its halflife.


A halflife is half the time it takes for something to decay.

For example:

Say you have a sheet of paper and you decide to rip it in half.

now lets say it took you five seconds to do that.

it will be represented like this:







Then you rip the paper up again:
(pictures drawn by me using MS paint. it is SO ANNOYING to drag those pictures up and down the page beacuse they mess everything up. grr.)



As you keep ripping it in half, we can tell how long it has been sinse it was whole from the chart.
that is how scientists use radioactive dating. By figuring out the halflife, with a fancy radioactivity machine, they see how much of the substance is gone to see how old it is.
Old things give off radioactivity, by the way.


GO TO THE UNIT PACKET ON PAGE 29.

The answere for the first quetions is no, beacuse there is almost nothing of the substance by the time you compare the halflife to how long ago the dinosours were alive. There will be so little of the substance, there would be no point in trying to figure out how old the object is.

PAGE 30.
do quetions 1-5 by figuring out the halflife.
Counts- unit of measurment


LAB TIME!!



we did a lab involving mnm's.
it was yummy.
we started out with a hundred mnm's in a cup. we shook the cup and poured the mnm's into a plate. the mnm's with the white M showing were considered 'decayed'. so we ate them.
we take what was left and repeat, untill the whole chart is complete.
then we ate the rest of the mnm's.
The lab is found on pages 31 and 32. do the quetions and the chart.

Yay! i'm done.

you know whats cool? google started to color code the tabs on your computer, in yellow, orange, green, blue, and purple. it's pretty neat.

I will now go procrasinate by overfeeding the fish in the tank on the right. I dont want to do math its so nghhhhghhhgh

Bojana, youre the next scriber!

(...sorry.)