Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Evidence of Evolution by Natural Selection Evolution by natural selection is a scientific theory that explains how Earth’s vast _______________ developed in the _____, continues to develop in the _______ and will continue to develop in the _____. Natural selection is a process by which _________________ over many generations as organisms with _____________________ traits survive and __________, passing their traits to their offspring. There is an abundance of evidence supporting the idea of natural selection: Fossils Fossils in young layers are more __________ to organisms living today than fossils found in deeper stratum Fossils appear in __________________ order Not all organisms appear at the ________________________ Transitional fossils show ______________ between groups of organism Comparative Anatomy Similarities in the basic pattern of anatomy is evidence of ___________ from a common ancestor (homologous vs analogous) Vestigial Structures/Features Vestigial features are those that are _________________ and/or ______________ structures that are homologous to a fully functioning structure in closely related species. _______ organism that has been studied in detail has vestigial organs including humans. Examples: tailbone, appendix and goosebumps in humans; pelvic bone in whales and some snakes; dewclaws on dogs and some other animals. Embryology Related species have similar _____________ development Examples: tails and gill slits in human embryos, arm buds on snakes, hair and teeth in baleen whales Geographical Distribution Related species are more likely to be found in areas that are ________________ to each other rather than are locations that are geographically ____________ but ______________________________. Example: Cacti species - only found in the Americas, even though suitable habitats exist on other continents. This would indicate that they have descended from a single common species and have not been able to cross the ocean. Island species Animals found on islands often _________________ animals found on the closes _____________. Islands get _______________ by organisms that dispersed from the nearest mainland Once on the island, the colonizing species is ________________ and may be faced with different _________________ _______________ The colonizing species will then _________ differently from its relatives on the mainland Example: no native amphibians or large land mammals have ever been discovered on remote ocean islands Galapagos Islands 13 varieties of land birds found nowhere else on Earth and ALL are finches Each variety is a result of descent with modification from a common finch ancestor which somehow reached the islands from South America Comparative Biochemistry Living organisms are highly similar at the __________ level, suggesting that they have descended from a common ancestor, which carried the information to make these molecules. All cells are made of the same basic types of organic compounds: ____________, ____________, ____________ and ________________________ In all organisms, organic reactions are controlled by ____________________ All proteins are made of the same ______________________ The major carbohydrate molecule of cells are six carbon sugars such as _____________ and its polymers, like starch and cellulose All cells carry out _________________ respiration - ___________________ All cells contain __________, which determines ____________ structure The _______________________ is universal (human DNA has been incorporated into the DNA of bacteria and animals) All species, studied in detail, also have _____________ - genes that have undergone __________ and ____ ____________ code for a ________________________ Example: Mammals have about 1000 functioning olfactory receptor (OR) genes that code for the receptors that detect airborne chemicals; dolphins, like all mammals, breathe though their noses, but have no need for a sense of smell in the air. Dolphins do have these same 1000 genes, but only about ______ of them are functional. Biologists suspect that after dolphins evolved an aquatic lifestyle, their OR genes were of no value, so any mutations that made the genes dysfunctional would have been __________ and _________________________, so over millions of years most of the dolphins’ OR genes have become pseudogenes.