Evidence of Evolution

Paul Andersen describes pieces of evidence that Charles Darwin used to support the idea of evolution and his process of natural selection. He begins with the following evidence use in the Origin of Species; artificial selection, biogeography, fossils and homologies. He finishes with a discussion of DNA and how it can be used to unravel the evolution of life on our planet.

Homeostatic Loops

Paul Andersen describes four important homeostatic loops in biology. He begins with a brief description of the elements of a homeostatic loop. He then describes how the hypothalamus helps us maintain a stable internal body temperature. He explains the role of the pancreas (insulin and glucagon) in regulating blood glucose. He explains how the thyroid and parathyroid glands (along with calcitonin and PTH) regulation blood calcium. He also explains how the pituitary gland (and ADH) help regulate the osmolarity of the blood.

Viruses

Paul Andersen describes the important characteristics of viruses. He starts with a brief description of origin theories. He then describes the two characteristics of all viruses; genetic information and protein coats. He also describes how some viruses use specialized envelopes to gain entry to their host cells. He also explains the lytic and lysogenic reproductive cycles.

Photosynthesis

Paul Andersen explains the process of photosynthesis by which plants and algae can convert carbon dioxide into useable sugar. He begins with a brief description of the chloroplast. He describes the major pigments in a plant (like chlorophyll a and b). He then describes both the light reaction and the Calvin cycle. He finishes with a discussion of photorespiration and strategies for avoiding this problem evolved in CAM and C4 plants.

Cellular Respiration

Paul Andersen covers the processes of aerobic and anaerobic cellular respiration. He starts with a brief description of the two processes. He then describes the important parts of the mitochondria. He explains how energy is transferred to ATP through the processes of glycolysis, the Kreb cycle and the Electron Transport Chain. He also explains how organisms use both lactic acid and alcoholic fermentation.

Bacteria

Paul Andersen describes the defining characteristics of the domain Eubacteria. He begins with a quick description of the phylogeny of bacteria and horizontal gene transfer. He then surveys the structures of a bacteria; nucleoid region, capsule, pilli, cell wall with peptidoglycan, flagella. He describes the differing morphologies and metabolism in different bacteria. He describes how bacteria can be Gram positive or Gram negative. He finishes with a brief discussion of quorum sensing.

Archaea

In this video Paul Andersen describes the defining characteristics of members in the domain archaebacteria. He starts with a brief description of the phylogeny of this group. He then describes the major characteristics on an archaea, such as differences in the phospholipids. He explains how they reproduce through binary fission and finishes with a discussion of archaebacteria diversity.

Eukarya

Paul Andersen discusses the defining characteristics of the members of Domain Eukarya. He starts with a brief description of the phylogeny of life on earth. He then discusses the major characteristics of eukaryotic cells. He explains how eukaryotic cells evolved from prokaryotic cells using endosymbiosis and infolding. He finally discusses the metabolism and reproduction found in eukaryotes.