This video is from the Khan Academy subject of Partner content on the topic of Crash Course and it covers The History of Life on Earth.
The video resource "The History of Life on Earth - Crash Course Ecology #1" is included in the "Ecology" course from the resources series of "Crash Course". Crash Course is a educational video series from John and Hank Green.
Paul Andersen explains how hugs between tissues can help maintain homeostasis. Countercurrent heat exchange allows heat to stay within the core of the body. Close contacts between the capillaries and alveoli allow our body to maintain the correct concentration of oxygen. Capillaries also hug the tubules in the nephron to maintain osmolarity and filter the blood.
Paul Andersen reviews the major components of the homeostasis. He explains how organisms respond to abiotic and biotic factors in their environment with feedback loops. He shows how responses can be behavioral or physiological.
Paul Andersen explains how disruptions in homeostasis can affect biological systems at all levels. He uses the example of dehydration in animals to explain how disruptions at the cellular level can affect an organism.
Paul Andersen shows how homeostasis reflects of evolution through time. The endocrine system shows continuity through flatworms, earthworms and vertebrates. However the respiratory system shows change as organisms move onto land. The importance of the Tiktaalik fossil as a transitional fossil is emphasized.
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.
360-degree animation of hominid skull - Aegyptopithecus zeuxis
360-degree animation of hominid skull - Australopithecus_afarensis (Hadar cranial reconstruction)
360-degree animation of hominid skull - Australopithecus afarensis AL 288-1 "Lucy"
360-degree animation of hominid skull - Australopithecus afarensis AL 288-1 "Lucy"
360-degree animation of hominid skull - Australopithecus afarensis AL 288-1 "Lucy"
360-degree animation of hominid skull - Australopithecus afarensis AL 288-1 "Lucy"
360-degree animation of hominid skull - Australopithecus africanus STS 5 "Mrs. Ples"
360-degree animation of hominid skull - Australopithecus sebida MH 1 (high angle view)
360-degree animation of hominid skull - Australopithecus sebida MH 1 (low angle view)
360-degree animation of hominid skull - Chimpanzee
360-degree animation of hominid skull - Gibbon (Technically Gibbons are not hominids)
360-degree animation of hominid skull - Gorilla sp. (adult)
360-degree animation of hominid skull - Gorilla sp. (juvenile)