In placental mammals, the gene SRY (Sex-determining Region Y) is a key factor that determines the forma- tion of testes (the Testis Determining Factor, TDF) and is located on the Y chromosome5,6. In most placental mammals, the X and Y chromosomes contain short homologous regions (...
Louis Bolk suggested that all mammals have the ability to express the traits we call atavisms, but humans just don't. This wouldn't make atavisms evolutionary throwbacks, just a genetic fluke. What is an Atavism? Four-year-old Jiaxue, of China, was born with hairy black moles covering ...
Are all Australian mammals marsupials? Why do marsupials produce immature babies? Why don't marsupials get rabies? How do dingoes survive? How long do marsupials live? Are any marsupials carnivores? How do dingoes reproduce? Why are marsupials and monotremes only found in Australia? What animals...
How do greenhouse gases work? Why is the endocrine system important? How does a rocket engine nozzle work? How would aspiration of urine from the bladder be accomplished? How does meteorology work? How did the biosphere form? Why do girls have periods? Why are humans placental mammals? How ...
If the change is beneficial, then it is likely that the offspring will do better than other offspring and so will reproduce more. Through reproduction, the beneficial mutation spreads. The process of culling bad mutations and spreading good mutations is called natural selection. As mutations occur...
Do we need to worry about bird flu spreading between humans? Just because bird flu has been found in mammals, it doesn't mean humans are next in line. As Dr Ward points out: "Humans rarely come into contact with wild foxes or otters, and potentially infectious contact is l...
Cells The cells are oxidized through an enzymatic processes, and the oxidation is the source of energy for humans and most other mammals. Oxygen is needed to build new cells and tissue, replace old tissue, dispose of waste material and reproduce more cells. ...
So how do eels reproduce, and where do they do it? Lucy Cooke digs into the ancient mystery. [Directed by Anton Bogaty, narrated by Adrian Dannatt, music by Jarrett Farkas]. science education animals evolution biology history sex TED-Ed animation ...
Superfetation is known to promote polyandry in some mammals because sequential litters can be fathered by different males38. We predicted, and found, that the evolution of superfetation is associated with the evolution of placentation34. A consequence of superfetation in Poeciliinae is that ...
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