scientific discipline concerned with naming and classifying the diverse forms of life
Fossils
a preserved remnant or impression of an organism that lived in the past
Evolution
defined broadly as: descent w/ modification; the idea that living species are descendants of ancestral species that were different from the present-day ones
Strata
rock layers formed when new layers of sediment cover older ones and compress them
Darwin's Observations of Life
Organisms are suited for life in their environments
There are many shared characteristics of life
The rich diversity of life
Paleontology
scientific study of fossils
Catastrophism
the principle that events in the past occurred SUDDENLY and were caused by different mechanisms than those operating today
Uniformitarianism
principle stating that mechanisms of change are constant over time
Lamarck's Hypothesis of Evolution
Based on 2 principles
Use and Disuse: parts of the body that are used become larger & stronger, those that are not used deteriorate
Inheritance of Acquired Characteristics: an organism could pass on these modifications to offspring
Adaptation
inherited characteristic of an organism that enhances its survival & reproduction in specific environments
NaturalSelection
a process in which organisms w/ certain inherited characteristics are more likely to survive & reproduce than are organisms w/ other characteristics
ArtificialSelection
the selective breeding of domesticated plants & animals to encourage the occurrence of desirable traits
Natural selection can increase the match between organisms and their environment over time.
If an environment changes, or if individuals move to a new environment, naturalselection may result in adaptation to these new conditions, sometimes giving rise to new species in the process.
Individuals do not evolve. Populations change over time.
Natural selection can only amplify or diminish heritable traits. Acquired characteristics cannot be inherited by offspring.
Environmental factors change from place to place and over time. A trait that's favorable in one place or time may be useless or detrimental in other places or times.
Homology
similarity in characteristics resulting from a shared ancestry
Homologous Structures
structures in different species that are similar because of common ancestry
Vestigial Structures
a structure of marginal, if any, importance to an organism that are historical remnants of structures that had important functions in ancestors (ex: some snakes have remnants of the pelvis & leg bones)
Evolutionary Tree
a branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms (each branch point represents a common ancestor of all species that descended from it)
Convergent Evolution
evolution of similar features in independent evolutionary lineages (do NOT come from a common ancestor)
Analogous
having characteristics that are similar because of convergent evolution, NOT homology
Biogeography
the study of the past & present distribution of species; influenced by many factors, including continental drift
Continental Drift
the slow movement of the continental plates across Earth's surface
Pangea
supercontinent that formed near the end of the Paleozoic era, when plate movement brought all the landmasses of Earth together
Endemic
referring to a species that's confined to a specific, relatively small geographic area
Aristotle thought that species were unchanging
Paleontology was developed by a French scientist, Georges Cuvier. He noticed that the fossils in the older strata were more dissimilar than current life forms. He saw that from one layer to the next, some new species appeared while others disappeared.
James Hutton said that Earth's geological features could be explained by gradualmechanisms still in operation today
Galapagos Finches
Volcanic islands near the equator
Collected finches that were similar but seemed to be of differentspecies
Beaks were different due to different diets
Darwin hypothesized that the Galapagos Islands were colonized by organisms that strayed from South America & then diversified
Traits are inherited from parents to offspring
All species are capable of producing more offspring than their environment can support
Due to a lack of food or other resources, most of the offspring do not survive
Individuals whose inherited traits give them a higher probability of surviving & reproducing in a given environment tend to leave more offspring than other individuals
This unequal ability of individuals to survive & reproduce will lead to the accumulation of favorable traits in the population over generations
Darwin saw a connection between naturalselection & overproduction
The Fossil Record
Fossils show us that previous organisms differ from present day organisms
Many species have become extinct
Show evolutionary change in various groups of organisms
Fossils can document the origins of new groups of organisms
Early cetaceans
Most mammals were terrestrial
Fossils show the transition from life on land to the sea
Embryological structures can compare early stages in development
All vertebrate embryos have:
Tail posterior to the anus
Pharyngeal (throat) pouches that develop into gills or parts of the ears in throat
We use continental drift to predict where fossils of different groups of organisms might be found
Carolus Linnaeus: developed the two-part system of naming organisms called binomial nomenclature
Darwin's concept of overproduction w/i a species was influenced by Thomas Malthus