EVOLUTION Flashcards
Longest expanse of geologic time
EONS
Next longest expanse of geologic time
ERAS
Third Longest expanse of geologic time
PERIODS
Shortest expanse of geologic time
EPOCHS
- (older than 540 million years ago) there isn’t as much detail of the geologic time scale. Scientists have divided this into Eons into the Proterozoic, Archaean, and Hadean.
- there were FEWER LIFE FORMS. These life forms are more difficult to identify and the rocks have been disturbed.
PRECAMBRIAN TIME
- The eon that began about 540 million years
- Rocks deposited in this contain ABUNDANT FOSSILS that DOCUMENT MAJOR CHANGES in life forms over time.
PHANEROZOIC
3 eras within the Phanerozoic eon
● Paleozoic
● Mesozoic
● Cenozoic
ancient life
PALEOZOIC
middle life
MESOZOIC
recent life
CENOZOIC
are divided into still smaller units called
epochs. Epochs of other periods are named early, middle, and late.
Cenozoic
He was studying a large shark that had been caught by fishermen and noticed its teeth resembled stony objects found in some rocks.
NICHOLAS STENO
- A French scientist named __________ studied fossils throughout the 18th century.
- He is considered one of the pioneers of paleontology.
GEORGES CUVIER
the complete disappearance of a species from the Earth.
EXTINCTION
The emergence of a new species
SPECIATION
● A geologist who disagreed with Cuvier and his theory of catastrophism.
● He favored uniformitarianism, the idea that the Earth had been slowly and steadily transformed over time by a series of tiny changes.
Charles Lyell
the movement of sediments by wind and water.
EROSION
influenced many scientists who were seeking to explain the adaptations, or variations present in living organisms that aided in their survival.
UNIFORMITARIANISM
hypothesized that animals adapted to their environment by their muscles and organs changing over time due to their use or disuse.
JEAN-BAPTISTE LAMARCK
● was a naturalist who had a copy of Charles Lyell’s book on geology with him as he traveled to South America on a ship, the HMS Beagle.
● In February 1835, he witnessed the Earth’s changes first hand during a massive 8.2 magnitude earthquake in Concepción, Chile.
CHARLES DARWIN
Darwin had discovered an important evolutionary process called ______________, where a species rapidly diversifies into new forms.
○ This occurs most often when the organism encounters a new or changed ecosystem.
○ New ecosystems have new niches, or spaces and roles that organisms within it play.
ADAPTIVE RADIATION
DARWIN’S BOOK
THE ORIGIN OF SPECIES
- Darwin felt that a similar process was occurring in nature, where traits favorable for a species surviving and reproducing in the wild were selected for.
- This is called ______.
NATURAL SELECTION
The first observation is that all species are capable of producing more offspring than the environment can support.
o This term for this level of reproduction is ____
SUPER FECUNDITY
The third observation
THERE ARE LIMITED RESOURCES
COMPEITION THAT occurs amongst members of
the same species
INTRASPECIFIC COMPETITION
COMPETITION THAT occurs between members of a
different species
INTERSPECIFIC COMPETITION
is the engine that drives the evolution; the extinction of some species and the speciation of new ones.
NATURAL SELECTION
Four ecological factors
Physiological stress
Predation
Competition
Sexual Selection
inappropriate levels of a critical environmental factor (Moisture, Light, pH)
Physiological stress
when one organism is hunted and killed by another
Predation
the result of other organisms attempting to use same resources
Competition
occurs when the female (usually) responds to specific behaviors or physical traits
Sexual Selection
The presence of predators will cause encourage the selection of individuals with traits to defend against or evade those predators.
PREDATION
● Likewise, both interspecific and intraspecific competition will ensure that weaker, “less fit” individuals survive and reproduce less often.
● This is the evolutionary basis of males that fight over access to females
COMPETITION
- Darwin struggled to understand why evolution would produce birds with brightly-colored males, once writing, “The sight of a feather in a peacock’s makes me sick.”
- A male bird that is able to grow a bright, colorful, large train of tail feathers must be healthy, and thus would be a suitable mate!
SEXUAL SELECTION
When the right level of an environmental factor is present, population levels will be growing or at their peak. This is the optimal range for that factor.
Physiological Stress
At the __________, levels of the factor are too high or too low. Weaker, less-adapted individuals are selected against.
zone of physiologic stress
At the _______, the population dies out.
zone of intolerance
are structural differences in coloration, body shape, musculature, etc.
Physical adaptations
include migration, or marking a territory
Behavioral adaptations
such as skin tanning, occur at the cell or tissue level in an organism
Physiologic adaptations
specific anatomical parts that show variations on a common design.
homologous structures
shrunken remnants of structures that were more useful in the ancestral form of a species.
Vestigial organs
is the study of the geographic distribution of species.
BIOGEOGRPAHY
Are sequences of DNA in chromosomes or sequences of
amino acids in proteins that are identical or nearly-identical.
Molecular homologies
total collection of genes
GENE POOL
