BIO 161 Lecture Notes - Lecture 1: Hypothyroidism, Frontal Bone, Pulmonary Artery
Document Summary
Maintain a relatively constant internal environment (homeostasis) Have an evolutionary history through which organisms change over time. **we share 99% of dna with chimpanzees. We all evolved from one single cell. Cultural heritage or patterns of our behavior passed from one generation to the next. *modification of our environment of our own purpose which may threaten the biosphere. Of the 92 naturally existing elements on the earth, only 25 play a role in the chemical process. Of these 25, 4 elements constitute more than 98% of biological matter: carbon (c), oxygen (o), hydrogen (h), and nitrogen (n). Matter - anything that has mass and takes up space. Elements - basic building blocks of matter that cannot be broken down by chemical means. Atoms - smallest units of an element that retain the elements physical and chemical properties, these bond to form molecules. Neutrons and protons make up the nucleus. Electrons are negatively (-) charged and orbit around the nucleus.