Change over a period of time. Evolution Change over a period of time.

Biodiversity The variety of organisms, the genetic information they contain, and the biological communities in which they live. Ecosystem Diversity The variety of organisms, the genetic information they contain, and the biological communities in which they live. Species diversity The number and variety of species on Earth. Genetic Diversity The different forms of genetic info carried by all organisms living on earth today. Gives rise to inheritable variation, the raw materials for evolution.

Charles Darwin Sailed for 5 years on a ship called the Beagle. Made and documented many observations of living things over 5 years.

Charles Darwin The Naturalist who first made the hypothesis about the way life changes over time. Observations that caused him to make this conclusion were made while on a voyage around the world on a ship called the H.M.S. Beagle.

Charles Darwin Darwin’s hypothesis was also shaped by new information about the world. Darwin’s original hypothesis is supported by a huge body of evidence and is now a theory.

Darwin’s Observations on the Beagle Large number of different species. Plants and animals are very well-adapted to environment. Variety of ways to survive and reproduce. Distribution of animals is not only determined by ecosystem type. How many species had gone extinct.

Darwin’s Observations (cont.) Fossil Diversity Collected bones and other traces of life. Where did all of the organisms come from and where have they gone? Fitness The ability of an individual to survive and reproduce, thereby passing on copies of its genes to offspring. Living Diversity Darwin found a great variety of living creatures. How did this diversity come to be? Adaptation Physical and behavioral traits that enable organisms to survive. Darwin noted how well suited organisms were to their environment.

Galapagos Islands His studies from the Galapagos Islands triggered Darwin’s thought. Animal life on one island was distinct and different from those on other islands. One could identify the island that a bird was from by looking at it, for example.

Galapagos Islands 1. Darwin wondered if the now separate species had once been of the same species, but had evolved differently when isolated from one another.

Darwin began to question the idea of all species remaining the same for several other reasons as well: 2. Homologous Structures Similar structures but in different organisms that developed from similar tissues in early development.

Homologous Structures

Darwin began to question the idea of all species remaining the same for several other reasons: 3. Vestigial Structures Structures that serve little/no purpose to the organism ( Example: Human tailbone). 4. Evidence that the earth was older than it was thought at that time. 5. Organisms produce more offspring than can actually survive.

Darwin’s Discoveries at Home 1. Although they looked different, birds from different islands of the Galapagos were of the same type, finches. 2. Darwin found the same of tortoises, marine iguanas, and plants from the islands. 3. He also found that island species resembled species from the mainland.

The Origin of Species by Means of Natural Selection…by Charles Darwin Provided evidence in support of the idea that life has changed, or evolved, over time. Gave an explanation of how and why evolution occurs.

Genetic Diversity Acted on by Natural Selection Mutation Change in genetic sequence that can sometimes change the characteristics of a organism. Gene Shuffling The shuffling of genes that occurs during the production of egg and sperm Adaptation A genetically controlled trait that increases an individuals ability to pass along copies of its genes.

Natural Selection Nature selects the most fit (well adapted) individuals to survive. A better adapted organism is more likely to survive to reproduce and pass on its genetic information. Over time, these adaptations will become more and more common in a population.

Some mutations change organism's characteristics. Mutations occur Some mutations change organism's characteristics. Bad Characteristic Good Characteristic Individual does not reproduce Individual Reproduces Trait becomes less common Trait becomes more common

Common Descent (a.k.a. The Evolutionary Theory) Modern day organisms are the result of the slow process of evolutionary change. All species have descended from other species over time.

Speciation Speciation Species The formation of new species. A population must evolve enough genetic changes(2 separate gene pools) so that breeding cannot occur between the emerging, genetically different groups. This is “Reproductive Isolation” vs. Darwin’s Finches: “Geographic Isolation” Species A group of similar looking organisms that can breed with one another and produce fertile offspring.

Evolutionary Tree/Cladogram A diagram that depicts the origin of new species.

Gene Pool Genetic Drift The group of alleles that is shared by members of the same species. The alleles in a gene pool will occur at a particular relative frequency unless under pressure by natural selection. Genetic Drift The random change in allele frequency of a gene pool

Pace of Evolution Gradualism Punctuated Equilibrium Slow and steady evolutionary change. Punctuated Equilibrium Quick periods of great evolutionary change followed by long periods of stasis.

Gradualism vs. Punctuated Equilibrium TIME

Adaptive Radiation Organisms of common ancestry evolve distinct adaptations to suit a particular niche. This pattern of evolution yields homologous structures. Example: Darwin’s Finches beaks were adapted to eating different foods

Convergent Evolution The pattern of evolution when unrelated species may independently evolve superficial similarities because of adaptations to similar environments. This pattern of evolution yields analogous structures - those which are similar in function and appearance, but developed from anatomically different parts because of separate ancestry. Example: Birds, bats, and insects all have wings, although the wing structure of each is very different.

Analogous Structures

Evidence Supporting Common Descent Fossil Records Fossils of many organisms have been found of organisms that do not exist today. Many current organisms are similar to very old fossils and fossil links often exist between them.

Evidence Supporting Common Descent Embryonic Development Similar stages of embryo development occur in different organisms. Organisms with similar developmental stages are considered to be closely related from an evolutionary standpoint.

Evidence continued Similar Proteins Proteins are responsible for most all body functions. Similar proteins are produced in different organisms. Organisms that have similar proteins are considered to be closely related from an evolutionary standpoint.

Evidence continued DNA Similar DNA sequences in different organisms point to close relation.

Molecular Clocks Because the simple mutations in DNA should occur at a somewhat constant rate, scientists use DNA evidence to estimate the time that different species branched from a common ancestor.

REVIEW Question: By what method does evolution occur?

Answer: Natural Selection

REVIEW Question: What term describes structures in different organisms that are similar in structure and were developed from similar tissues?

Answer: Homologous Structures

REVIEW Question: What term describes a mutation that increases an individuals ability to pass along copies of its genes?

Answer: Adaptation.

REVIEW Question: Name the scientist whose work formed the basis for the Theory of Evolution?

Answer: Charles Darwin

This is a section for you to write in on the big open spot on your notes Other scientists who influenced Darwin Hutton and Lyell Earth was very old. Earth had changed very slowly over time. Processes that changed Earth in the past are the same as those at work today. Lamarck Life had changed over time. (his hypothesis about how was incorrect) Malthus Organisms produce more offspring than can survive.

An individual cannot evolve. Evolution can only occur in a population. Natural selection is survival of the most well-adapted, not always the “fittest”. Mutations are random. Some are beneficial, but most are not. Many mutations would be required to produce new species. Evolution occurs over hundreds of thousands of generations and requires a great deal of time for most populations.