Biology and the Tree of Life

• Biology describes the scientific study of life.

• Despite diversity, all living things share some basic characteristics.

• All living things have characteristics such as: order/organization, reproduction, growth and development, evolution/adaption, response to stimuli, energy processing, and homeostasis/regulation.

• All living things have to have all seven of these characteristics listed above.

• Taxonomy is a term that describes the branch of biology that identifies, names, and classifies organisms.

• Systematics is a term describing the study of evolutionary relationships between organisms.

Eukaryotic Cells vs. Prokaryotic Cells

• Eukaryotic cells have a true nucleus (membrane-bound), have cells with membrane-bound organelles, are usually multi-cellular, and are usually visible to the naked eye.

• Prokaryotic cells do not have a true nucleus, lack membrane-bound organelles, are always single-celled, and are always microscopic.

• All living things belong to one of the following domains: bacteria, archaea, or eukarya.

  Domain Archaea

• They are prokaryotic cells from various shapes, live in extreme environments, absorbs food, and have unique chemical characteristics.

Domain Bacteria

• They are prokaryotic cells of various shapes, can adapt to any environment, absorbs food, and have unique chemical characteristics.

Domain Eukarya

• They are eukaryotic cells that have a true nucleus, have complex inner and outer structures, and have the largest body mass and size out of the other domains. The website below is used for this section of notes: https://www.bioexplorer.net/domain-eukarya.html/

Water and Carbon: The Chemical Basis of Life

• Matter is a term describing anything that has mass and occupies space.

• Matter comes in three states.

• All matter, both living and non-living, is composed of elements.

• An element is a substance that is composed of a type of atom.

• Six elements make up 99% of the body weight of organisms. The most common elements are carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur.

Atoms

• An atom is the smallest part of an element that displays the property of the element. It contains subatomic particles.

• Each element is represented by one or two letters to give it a unique atomic symbol.

• Atomic mass is located at the top left of an atomic symbol and atomic number is located at the bottom left of the atomic symbol.

  (These notes are from past Biology 120 lectures by Dr. Davenport at Reinhardt University as well as the textbook which the information comes from is linked below.) https://openstax.org/details/books/biology-2e