Kin Selection: natural selection where there is favoring of behavior by individuals that may decrease their chances of survival but increases that of their kin; when a grandmother is present, there is more percent of newborns surviving; natural selection acts on traits.Eusocial Species: cooperative breeding, division of labor, higher order of social organization. 9/25/2018Big Bang- Inflation Period: Big Bang the size of a golf ball, happened in about 10^3 milliseconds. This occurred 13.8 billion years ago. Inflation is the exponential increase of the universe. - About 300 million years ago, atoms of light began forming, making the first stars possible at about 400 million years ago. - The sun was made about 4.7 billion years ago, and the earth came about around 4.6 billion years ago—life on earth began around 3.6 billion years ago. At around 2.8 billion years ago, photosynthesis started occurring in bacteria. - The oxygen catastrophe is when there was too much oxygen and it reacted with the iron, leading to a huge extinction of many species. Also led to the Earth cooling (ice age). Timeline of Life on Earth-1stvertebrate- 485 million years ago. -1stvertebrates on land (tetrapods)- 375 million years ago. -1stmammal- 230 million years ago.-1stbirds- 160 million years ago. -1stprimates- 60-65 million years ago. -1st apes- 25 million years ago.-First hominins around 7-6 million years ago. Titkaalik Rosae represents a slow shift from ocean towards land. Basic Animal Body PlanEmbryos start as a clump of cells that for a disk. Primitive streak=site of gastrulation (also establishes bilateral symmetry and germ layer)The disk then folds to form 2 tubes One is for your guys, the other for your brain and spinal cord. As the neural tube closes, the location of the vertebrae can be seen.Vertebrae is formed from somite, which develop into sclerotomes, and through chondrification and ossification, the vertebral unit is formed. 3 germ layers are formed during gastrulation. EctodermEndodermMesodermform the gastrula, which is when the embryo implanted into the uterus.