The Theory of Evolution Chapter 13 The Theory of Evolution

Charles Darwin Charles Darwin – visited the Galapagos Islands and noted that groups of animals varied from island to island but yet were similar. He observed 13 species of finches. Each had a type of beak and coloring adapted to it’s environment/ island. Upon closer and internal observation, Darwin concluded that they must’ve come from a common ancestor. Evolution – the development of new types of organisms from preexisting types of organisms over time. (an inheritable change in characteristics)

Charles Lyell (1797-1875) believed in Uniformitarianism – which states that the geologic processes shaped Earth in the past continue to operate in the same way today. Another belief by Georges Cuvier believed in Catastrophism – which states that sudden geologic catastrophes caused the extinction of large groups of organisms at certain points in the past

Natural Selection Natural Selection – Process by which individuals that are better adapted to their enviroment survive and reproduce more successfully than less well adapted individuals do: this explains the mechanism of evolution Adaptation – changes in population over time

Evidence of Evolution Fossil – remains or traces of an organism that died long ago. Biogeography – the study of the locations of organisms around the world. Darwin observed animals that seemed closely related but yet were adapted to different environments. On the flip side – he also saw animals that did not seem related but had similar adaptations to similar environments that were far apart.

Divergent evolution – process in which the descendants of a single ancestor diversify into species that each fit different parts of the environment (accumulation of differences b/t populations that once formed a single population) Convergent evolution – process by which different species evolve similar traits

Anatomy & Embryology Anatomy – the study of body structure Embryology – the study of the development of organisms Homologous Structures – anatomical structures that occur in different species, that originated by heredity from a structure in the most recently common ancestor of the species

Anatomy & Embryology Analogous structures – closely related functions but do not derive from the same ancestral structure Example: wings Butterfly wings are different from bat wings which bird wings but all are used to fly

Anatomy & Embryology Vestigial structures – structures that serve no function but resemble structures with functional roles in related organisms (tail bone) Embryonic development is also evidence of a common ancestor – if you look at the development of vertebrates, they look very similar in the beginning of their development.

Anatomy & Embryology If a group of animals from similar species have the same protein in their blood – it can mean that they are related to a common ancestor

Coevolution – when two or more species evolved adaptations to each other’s influences Example: Plants have evolved so that the animals that eat them also spread their pollen. As a result, plants and their pollinators coevolved. Artificial selection – when humans chooses an individual that will parent the next generation, based on a certain characteristic

CHAPTER 14 Classification

Classifying Organisms Biodiversity – the variety of organisms considered at all levels from populations to ecosystems Taxonomy – the science of describing, naming, and classifying organisms Taxon – any particular group within a taxonomic system.

Dichotomous Key dichotomous key, is a method of deducing the correct species assignment of a living thing. As the alternative name implies, it works by offering two (or sometimes more) alternatives at each juncture, and the choice of one of those alternatives determines the next step. For each level of distinction, there is normally a further indent. Some keys use different numbering systems.

Dichotomous Key Are you above or below 5’4. Do you have hair below or above your shoulders? Are you right or left handed? Do you wear glasses? Do you have a job? Do you play a sport for the school? Then questions get specific with your name.

Levels of Classification REMEMBER IT BY KING PETER CAME OVER FOR GRAPE SODA KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES As you move through the hierarchy from kingdom to species, animals become more similar in appearance.

Levels of Organization Binomial Nomenclature: the scientific name with two parts given to an organism: the genus name followed by species identifier. Example: Human: Homo sapien Domestic Dog: Canis familiaris

PHYLOGENETICS Phylogenetics – the analysis of the evolutionary or ancestral relationships among taxa Phylogenetic diagram or phylogenetic tree – looks like a family tree and has a branching pattern that indicates how closely related, by their evolutionary relationships, a subset of taxa are thought to be. (can change upon new discoveries)

Cladistics Cladistics – a system of phylogenic analysis that uses shared and derived characteristics as the only criteria for grouping taxa Shared character – feature that all members of a group have in common – such as scales for reptiles or hair in mammals Derived character – a feature that evolved only within the group under consideration. Only birds have feathers, among living and extinct animals – birds are the only animals to have feathers so you can hypothesize that feathers evolved strictly within the bird lineage

Cladograms Clade – organisms that share one or more derived characters probably inherited from a common ancestor. Cladograms – a phylogenetic diagram representing common ancestors Starts with out-group – an organism that is distantly related to the other organisms Exploring Further pg. 308

Cladogram

The horse Chordata Mammalia Perissodactyla Equidae Equus Caballus

Donkey Chordata Mammalia Perissodactyla Equidae Equus Asinus

Crossing Species Although donkeys and horses are similar they are not of the same species. They can produce offspring but their offspring is sterile. The same is true for lions and tigers which produce sterile ligers