Anthro2050 1st Edition Lecture 6 Outline of Last Lecture I More on Natural Selection II Evidence for Evolution Outline of Current Lecture I Evolution and Tinkering II Sexual Selection Current Lecture Evolution and Tinkering Evolution and natural selection are subject to the laws of physics and biology New traits and characteristics cannot be added randomly and usually come from nature tinkering with components that are already there Several examples are included Lungs ancient aquatic creatures that lived in stagnant water found that if they swam to the surface and gulped at the air they could get more oxygen Over a long time sacs formed to collect this air and send it to the rest of the body This marked the beginning of lungs and similar structures we see in animals today There are some fishes and aquatic mammals that show that transition between gills and lungs Eyes eyes have evolved three different times and all three designs work if there was one design for eyes that worked best it would be in all animals however these designs show animals developing in the best way for their environments Even animals that live fully in the dark although they no longer use their eyes still develop them because they were used in the past Since evolution is limited by what is available and what is possible according to the laws of nature there are some animals that just simply cannot exist Although we cannot predict evolution one hundred percent we know the limitations and possibilities All of the animals that have existed and do exist tigers snakes pterodactyls etc These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Animals that could exist and are similar to modern animals unicorns narwhals Animals that simply cannot exist humans with wings Sexual Selection a sub sect of natural selection favors traits that increase the success in competition for mates causes animals to evolve to have traits desired by the opposite sex in terms of reproduction sexual dimorphism physical differences between males and females in a species largely influenced by parental investment the amount an individual invests in offspring in most animals males only have to invest their sperm and that s all in most animals women invest the egg carry the child and rear the child through their early life males therefore tend to be big strong and more colorful than the females and are more concerned with the quantity than the quality of their mates females tend to be smaller and less colorful than the males and are more concerned with the quality than the quantity of their mates if they are going to invest so much in a child they want the father to be of high caliber due to this males and females behave and look differently in most animal species
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