Analyzing the Evidence February 24th/25th, 2009

First Things First… Hypothesis= An educated guess as to why we are seeing what we observe. A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation. An assumption. Example: The dog barked because he saw a cat. Theory= An explanation as to why we are seeing what we observe. This explanation has been tested over and over again and shown to be true. Also there is a significant amount of evidence to support it, how ever it has yet to be proven as true. Example: Dinosaur extinction by meteor. Law= Something known to be true. It never changes. Example: The Law of Gravity

Evolution The theory of evolution states that all the animals and plants in the world today developed from earlier, different species. As evidence for this theory, all species today share some characteristics with their ancient ancestors.

Evidences of Evolution 1. Biogeography- the geographical distribution of organisms.

Fossil Record – Preserved remnants or impressions left by organisms that lived in the past.

Comparative Anatomy Homologous structures- characteristics resulting from common ancestry. Vestigial organs- structures that have little importance for organisms but are historical remnants of evolutionary ancestors.

Molecular Biology Comparing differences in the amino acid sequence of important proteins such as Cytochrome c and Hemoglobin.

Comparative Embryology As vertebrate organisms develop as embryos, distinctive characteristics of their class appear.

Why is Evolution So Controversial Anyway? http://www.pbs.org/wgbh/evolution/library/11/2/e_s_7.html