What?!?!? Evolution involves Genatics?

Today in biology class, we talked about way that a species can eventually become two or mare than that. Basically it is all in the genetics, I genes change then the species becomes different. How or why do the genes change? Well one main reason is genetic drift. Genetic drift is when a number of species are moved to a different environment or the environment changes very fast in a small amount of time. This causes the animal to adapt in order to survive, or natural and/or artificial selection takes place. Over time the species becomes different creating a whole new species.


We also talked about other things like speciation. This is the ways a species evolves over time. There are two ways a species can evolve: punctuated equilibrium and gradualism. Punctuated equilibrium is when a species has long periods of stability and the short periods of rapid change. Gradualism is when a species changes at a slow steady rate. For this to happ3en you need several things; you need complete isolation and that the organism, and the organism cannot interbreed with another species.



Another thing that can spark a movement to change in a species is adaptive radiation. Adaptive radiation is when a species changes due to environment. If the environment changes so does the species in order to survive. One prime example is the finches on all the Galapagos Islands. They are slightly different on each island.

We also brushed over some other topics, these include;
Convergent Evolution: two different species, that are similar due to living in the same environment (ex. Butterflies and birds).
Co-evolution: organisms with close ecological relationships (ex. Plants and insects)

We then shifted subjects, and moved onto dating (not the kind where two people go out, but the kind to tell how old a fossil is). There are two ways scientists can tell how old a fossil is. One way is relative dating. Relative dating is were scientists look at the layer of rick or ground were the fossil is found, and depending on how old the layer is, that’s how old the fossil should be. The other way is through carbon dating. Since all thing need carbon, everything will have carbon in it. One an organism dies, it stops creating carbon. The carbon then starts to decompose. Carbon 14 and any other chemical will always decompose at the same rate. For carbon, half will be gone in 5770 years. This is known as a half life. A half life is how long it takes for half the mass of a chemical to decompose. So to tell how old a fossil is all you need to do is know how much carbon was originally there, know how much is left and then by counting half lives you can tell how old a fossil is. The only drawback is if there is not enough carbon then this wont work.

Don’t forget the homework!!:
-Read 19.3 and do a flow map on that
-finish UP 33-35
- Also don’t forget about your TV add due 2/28
-Test Wednesday


Here are some useful videos if you need any additional help;

http://www.youtube.com/watch?v=81dWTeregEA
This one explains carbon dating well

http://www.youtube.com/watch?v=tKj2s3VVI0M
This one show great example of Convergent evolution for animals with wings.