The following is a scientific theory. No one fully understands the truths that this ancient world holds. We must all decide what we believe is true for ourselves The best way to accomplish this is by looking at things from all perspectives and then choosing. Here is one perspective for you to consider.

The Theory of Evolution

Evolution Defined Evolution: -Gradual change over time -Modification over generations how did this theory come to be you ask….let’s start from the beginning…

Age of the Earth -Earth is 4.5 billion yrs. Old -How do we know? -Geologic Time Scale - record of rocks -     rocks are made up of radioactive isotopes (like Carbon 14) -     half-life- the amount of time it takes half of the radioactive isotope to break down. (It takes about 5,700 years for half of the Carbon 14 in an organism or object to decay.)

Evidence For Evolution 1)   -fossils – similar fossils for similar organisms

Pterosaur Chicken

Fossils -Fossils ~ preserved remains of ancient organisms -they can also be “carbon dated”

Fossils -Where do we find fossils? - mostly found in sedimentary rock -    some fossils are changed into rock (petrified).

Embryos 2)  -embryological development- organisms with similar embryos may be related

Embryology -embryo- earliest stage of development -reptiles, birds, and mammals all have similarities (these embryos are not exactly alike however) Haeckel's drawings

Homologous Structures 3)  -Homologous structures – structures that are similar, but modified for different functions (whale fin, bat wing) (analogous structures- ones that have similar function, but different ancestry(wings, fly vs.bird)

Homologous Structures

Analogous

Vestigial Organs 4)   -Vestigial organs- serve little or no purpose, but did at one time (claws on a snake, your tailbone)

Vestigial Organs

DNA 5)    -DNA -the more closely related the organism, the closer the DNA will match

DNA