The Beagle sails from Rio de Janeiro to Montevideo; Darwin reads John Milton’s Paradise Lost and Volume II of Charles Lyell’s Principles of Geology; upheaval and anarchy in Montevideo; arrival of new ship’s artist Conrad Martens; fraternising with the gauchos and discovering the bones of an extinct megatherium; the story of the three Yaghans from Fitzroy’s first voyage on the Beagle; leaving Montevideo for Tierra del Fuego.
‘Warm blood’ and an explanation of what it means to be endothermic. How homeothermic endotherms are able to maintain a constant body temperature within a narrow temperature range; the strong relationship between ‘mass specific basal metabolic rate’ and body mass; surface area to volume ratios; mechanisms by which the body loses and gains heat; abandoning endothermy by hibernation and torpor.
Summary of the Ptolemaic Earth centered view of the Universe; how the Earth centered (geocentric) view held currency for more than 1000 years; Copernicus and the sun centered (heliocentric) view of the Universe; why Copernicus harbored doubts about the sun centered model; an explanation of the stellar parallax; using the geometry of the Earth to calculate distance. ‘De Revolutionibus’ goes into print in 1543.
What makes reptiles ‘cold blooded; why ‘ectothermic’ is a more accurate description of reptiles than ‘cold blooded.’ How ectotherms ‘thermoregulate’ their core temperatures by adopting different types of behavior. Physiological adaptions of ectotherms including changing skin color, freeze avoidance and freeze tolerance. Why ectotherms make excellent ambush predators. The hearts of ectotherms.
Difference between brown dwarfs and stars; how brown dwarfs’ early evolution is similar to that of protostars; gravitational contraction and how brown dwarfs burn deuterium and lithium; how matter inside brown dwarfs becomes degenerate; electron degeneracy explained and how this electron degeneracy impacts on size; difficulties in discovering brown dwarfs. Weather systems of brown dwarfs.
Tension force and horizontal pulling forces. How Newton’s Laws of Motion can explain the force of tension; how tension remains constant when the forces pulling on a rope from opposite ends and in opposite directions become unbalanced; tension and vertical pulling forces ; explanation of tension in a cable which is attached a light to a ceiling; tension in the cable of an escalator; tension at the molecular level.
The Beagle reaches Rio de Janeiro in April 1832. Darwin visits a slave plantation in the interior and is disgusted by what he sees of the treatment of black slaves. Darwin is captivated by the rainforest and all the specimens he observes for the first time. Darwin returns to Rio where he spends time discovering more new species including many invertebrates which he collects and preserves. The Beagle sets sail for Buenos Aires.
This article discusses ways in which plants have adapted to disperse their seeds after fire has destroyed the landscape. Species explored include the Lodgepole pine trees and two Banksia species from Australia; how seeds disperse through the effects of smoke shock (Whispering Bells) and heat shock (Sweet Wattle) following forest fires; how species indirectly benefit from forest fires to help disperse their seeds.
In this article we investigate the force of friction which opposes the forward motion of objects; we look at the force that needs to be applied to an object before friction can be overcome and forward motion can occur. We explain static and kinetic friction, how friction comes in pairs and represents the interaction between two different surfaces; what happens when a surface is frictionless, how friction can help or harm.
This science artilce investigates convergent evolution in different organisms and how two totally unrelated species can evolve to resemble each other in different ways. We investigate convergent evolution in color, body shape, body organs, defensive spines, tongues, eyes, animal behavior, brain function, mimicry and in extinct species. We also look at convergent evolution in animals, plants, fish, insects and reptiles.