The theory that species change over time. Evolution The theory that species change over time.

Evolution: An introduction Evolution: change in the characteristics of a population from one generation to the next. What causes evolution to occur? Is evolution necessary for living things to survive? Are living things evolving today?

Evolution of the Motorcycle

Evolution Introduction Activity Come up with an example of something non-living that has evolved. Describe: the changes it has undergone Include a timeline the circumstances responsible for the changes and/or the benefits of the changes Draw, print, paste your item through the ages (at least 4 images)

Evolution Evolution is caused by changes in the environment: Catastrophism = theory that natural disasters such as a floods or volcanic eruptions lead to changes in the environment, which then lead to evolution. Gradualism = theory that environmental change occurs gradually or slowly, which leads to gradual, slow evolution.

Charles Darwin The person who popularized the theory of evolution was Charles Darwin. In the 1830’s Darwin visited the Galapagos Islands, a small group of islands off the coast of Ecuador in South America. Influenced by his experience, he decided to write his book, “On the Origin of Species” in 1859.

Natural Selection Darwin proposed that Natural Selection was responsible for the changes that organisms experience over time. Natural Selection = the process by which organisms with favorable variations survive and produce more offspring.

Natural Selection Variations are the physical differences between the individual members of a group. Favorable variations become Adaptations: an inherited variation that increases an organism’s chance of survival in a particular environment.

Natural Selection Isolation is the condition in which two populations of the same species cannot interbreed anymore due to the fact that they have evolved separate from each other for so long. Species = a group of organisms so similar to one another that they can reproduce and have fertile offspring.

Grand Canyon Squirrels (isolated for 10,000 years) Natural Selection Grand Canyon Squirrels (isolated for 10,000 years) North = Kaibab Squirrel South = Albert Squirrel

Natural Selection Natural selection occurs in nature without the intervention of humans. Artificial selection is the process by which humans change a species by breeding it for certain traits. This only works if the trait is heritable (able to be passed down from one generation to next).

Artificial Selection

Artificial Selection

Natural Selection One last term in natural selection is extinction (when a species disappears permanently). Most extinctions are caused by natural disasters, and/or humans.

Grizzly bear still alive and found in different parts of world. Ursus horribilus California Grizzly Ursus californicus Last one shot in 1922.

Evidence of Evolution Fossils = The trace or remains of an organism that lived long ago, preserved in sedimentary rock. Note: it is normally the harder part of an organism (teeth, bone, shell) that becomes a fossil. Paleontologist = scientists who study fossils.

Evidence of Evolution Over millions of years, dirt, sand and rock get deposited on the ground in layer after layer after layer. Between these layers dead organisms are often trapped.

Evidence of Evolution When the weather or seismic activity (when the ground moves) exposes the layers, fossils are found.

Evidence of Evolution Any living organism can leave a fossil, even plants! As long as the organism is buried and subsequently replaced by minerals.

Evidence of Evolution: DNA

Evidence of Evolution Biogeography, the study of the distribution of organisms around the world. Agile Mind - 11. Evidence of Evolution – The evidence for evolution – slide 6

Biogeography

Evidence of Evolution: Vestigial Structures

Evidence of Evolution: Vestigial Structures

Evidence of Evolution: Vestigial Structures

Evidence of Evolution: Vestigial Structures

Evidence of Evolution: homologous structures

Evidence of Evolution: Analogous Structures

Evidence of Evolution: Analogous Structures

Evidence of Evolution Vertebrates are any organism that has a backbone. Embryos are the organism in a very early stage of life.

Fish Salamander Turtle Chicken Pig Sheep Rabbit Human

Human Evolution For human evolution just understand that modern humans have only been around for about 100,000 years. According to current data, hominids (human-like organisms) have been around for about 10 million years. No, we did not “come from” monkeys, but we did evolve from a common ancestor.

Australopithecus afarensis

Australopithecus africanus

Paranthropus robustus

Paranthropus boisei

Homo habilis

Homo erectus

Homo heidelbergensis

Homo neanderthalensis

Homo sapiens (Cro-Magnon)

Homo sapiens sapiens

Homo floresiensis “The Hobbit” 3 ½ feet tall Small brain Huge feet Possibly left Africa as A. afarensis, reached S.E. Asia, evolved, disappeared.