Welcome to Darwin Day!
Considered to be the father of evolutionary ideas Sailed upon the HMS Beagle for 5 years around the world Gathered data and specimens from South America Galapagos Islands, as well as the South Pacific Frequently left the ship for months to observe and collect specimens; rejoining the ship miles down the coast Carefully documented sites and ideas descriptions
Before leaving on his journey, Darwin believed that species were a divine creation, unchanging, and existing as they were naturally created.
Darwin observed many species in their natural geographical location: many types of animals never seen in his homeland (giant apes) sea shell fossils on mountain tops evidence of earthquakes in Chile where sections of Earth had been lifted more than a meter varied finches from the Galapagos Islands with special interest in beak shapes many variations of tortoises from the Galapagos Islands with different body shapes active volcanoes (land being created)
Variation is a difference in a physical trait. Galápagos tortoises that live in areas with tall plants have long necks and legs. Galápagos finches that live in areas with hard-shelled nuts have strong beaks. Short neck & legs domed tortoise Saddle-backed tortoises have a high shell edge, allowing them to stretch their long necks
An adaptation is a feature that allow an organism to better survive in its environment. Species are able to adapt to their environment. Adaptations can lead to genetic change in a population (more info later )
Darwin found fossils of extinct animals that resemble modern animals. Darwin found fossil shells high up in the Andes mountains. (How did they get way up there?!) Darwin found a fossil of a Glyptodon, a giant armadillo, in Argentina. modern day armadillo
He saw land move from underwater to above sea level due to an earthquake. Darwin extended his observations to the evolution of organisms. The trilobite, an early marine invertebrate that is now extinct, was found in a loose rock bed in Ohio.
1. Descent with modification: The newer forms appearing in the fossil record are descendants of older species. Infers that all organisms are descended from one or a few types of life. All vertebrates, such as birds and mammals probably descended from a vertebrate that lived in the distant past. i.e., all had a common ancestor. Similar organisms arise in the same geographic location; modern kangaroos evolved from a nowextinct ancestor very much like them.
Natural selection is how evolution occurs (the mechanism that causes evolution to occur) Also called Survival of the Fittest
Darwin noticed a lot of variation in domesticated plants and animals. Artificial selection is the process by which humans select traits through breeding (a.k.a. selective breeding). neck feathers crop tail feathers
1. Variation - Individual organisms in nature differ from one another 2. Overproduction - Organisms in nature produce more offspring that can survive, and many of those that do survive do not reproduce. Because more organisms are produced that can survive, members of each species must compete for limited resources. 3. Adaptation - Because each organism is unique, each has advantages and disadvantages in the struggle for existence. 4. Descent with modification - Individuals that are best suited to the environment survive and reproduce most successfully (called fitness) Those characteristics are passed down to the next generation. Species change OVER TIME. Over long periods, natural selection causes changes in the characteristics of a species, such as in size and form. New species arise and others disappear.
Natural selection can act only on existing traits. Structures take on new functions in addition to their original function. five digits wrist bone
Microevolution: Changes WITHIN a species over time. It results from genetic variation and natural selection within a population of organisms. (antibiotic resistance) Macroevolution: Evolution that occurs BETWEEN species. It focuses on how GROUPS of organisms change over a period of time. (mass extinctions)
1. In the early 1800s in Manchester, England, the trees were light in color and speckled with grey & green from a lichen that lived on the tree trunks. Birds were the natural predator for the peppered moth. The light colored peppered moth was the more prevalent color of peppered moth during this time. Why?
2. During the 1840s-1850s the Industrial Revolution began in England and soot covered the trunks of the trees due to the pollution released by the industries. What do you think happened to the peppered moth population?