Chapter 22 Flashcards
Aristotle Thoughts on Origin of Species
Species were in unchanging and perfect
All species can be organized in a ladder according to increasing complexity called the Scala Naturae
Evolution
Descent with modification- changes in generations over time
Change in the genetic makeup from one species into the next
Old Testament on the Origin of Species
God created each species and therefore perfect
Scientists observed that organisms were adapted to environment and thought God created them for a purpose
Carolus Linneaus on the Origin of Species
Wanted to classify earths diversity
Organized species according to their similarities and made categories more general
Created binomial system that is used today
Georges Cuvier
Started paleontology
Saw the older the rock strata were the more different fossil species were from current day
Saw that species from one strata did not appear in the other strata believed that extinctions happened oftenkrrr
Believed in Catastrophism- states that a natural disaster occurs between rock strata
James Hutton
He believed that the earths geological features could be explained through gradual processes of the earth
Ex. Valleys formed through rivers eroding rock
Charles Lyell
Used Huttons ideology in his idea of uniformitarianism that states that processes of change in the earth remain constant. This means that the rate at which the earth is changing is the same as the past.
This ideology showed that the earth was much older than originally predicted because Earth would have taken much longer to form it’s mountains and valleys
Lamarck use and disuse and inheritance of acquired characteristics
Lamarckian idea that stated body parts that are used more often become stronger in future generations
Also stated that characteristics gained in an organisms lifetime can be passed down to its offspring
Even though these ideas are wrong, Lamarck was one of the first scientists to accept that species change over time to better adapt to their environments
Adaptations and natural selection
Adaptations are characteristics that help a species survive in it’s environment
Natural selection is the process in which organisms with certain beneficial characteristics have more offspring than other species
Darwin’s observations and inferences
Variations in traits exist
These variations are heritable
Species overproduce
There is competition for resources, not all species survive
Individuals who have beneficial traits that help them survive have more beneficial traits than those who don’t
This allows an increase of this favorable trait in the populations
Evidence of evolution in the fossil record
There are often fossils of transitional species from two different species ex. Fish to land- Tiktaalik
Homologous Structures
These are limbs or other structures that are similar in many different species
This gives evidence for evolution in that it suggests a common ancestor
Vestigial Structures
Remnant structures that were useful for there ancestor species but are not anymore
Ex. Snakes have a pelvic leg vestige
Analogous Structure
Similar structures that appear in two species that evolved independently from eachother because of their similar environments
Ex. Sugar glider and flying squirell
Convergent Evolution
When two species evolve independently of eachother and have the same characteristics because of their similar environments
Sugar glider and flying squirrel
Fish that live in Antarctic and the arctic
