Changes over time Flashcards
James Hutton
Old earth theory, Geological forces shaped the earth over extremely long periods of time
Also the earth is millions of years old, not thousands
Thomas Malthus
Predicted that the Human population will grow faster than the earth can allow for (space and food supplies)
Jean-Baptiste Lamarck
Hypothesis of the inheritance of acquired traits
organisms followed a use it or loose it pattern for their traits that get passed on to the following generations (and the cycle repeats)
Charles Darwin
Sailed around the world, visited many ecosystems, and observed the diversity, he concluded the following about Evolution
- Natural Selection
-Survival of the fittest
- descent with modification
Charles Lyell
Explained that process happening now have the same geological patterns and features as what happened in the past
ex. Erosion continues to carve out canyons
Artificial Selection and another name
Selective breeding
Nature provides the variation and humans select and reproduce the traits that they find useful
ex. cows with more milk, largest hogs, fastest horses
Natural selection and another name for it
Survival of the fittest
The individuals who are best suited for the environment will survive and pass on the genes to the next generation
Struggle for existance
Members of each species compete regularly to get necessities
one small advantage can be the difference
big and strong does not make the winner
Adaption
When a organism becomes better suited for the environment around them
Survival of the fittest
an individuals ability to survive and reproduce
Descent with modification
Each living species has descended with changes from other species over time
ALL living things are related to each other (common ancestor)
Common descent
All species (living and extinct) came from a common ancestor
typically connected by the tree of life
Development of sexual reproduction
Sped up evolutionary rate
increases genetic variety
Fossil Evidence
shows the changes between species that lived in the past and those alive today
Used to compare similarities between species that are extinct and their modern relatives
Fossil
any evidence of and an organism that once lived
Law of Superposition
in any undisturbed sequence of earths layers the old layers are at the bottom and the new layers are at the top
Comparative Morphology
many species have a common anatomical physical structure
branch of science where living things are compared to understand their development among other species
Analogous structures
serve the SAME PURPOSE in DIFFERENT SPECIES but evolved independently
Homologous structures
are SIMILAR BODY PARTS found in DIFFERENT SPECIES for DIFFERENT PURPOSES
Vestigial Structures
body parts that no longer have a function in a species
Embyology
The study of living things before birth many organisms are very similar in appearance and
Embryo
a developing organism at a stage prior to birth or hatching
Biochemical evidence
organism that look similar today are believed to have a more recent common ancestor than organisms that look different (however you shouldn’t rely on outward appearances)
Gel electrophoresis
you are able to look at similarities in DNA and tell how closely related organisms are
Speciation
The process of a new species formation (though the course of evolution)
Directional selection
a shift in the population in favor of another trait
Stabilizing selection
genetic diversity decreases and the middle ground is favored (population stabilizes on one trait)
Disruptive selection
When the extremes are favored on both sides
normally 2 populations
Reproductive isolation
occurs when members of two populations cannot interbreed and produce fertile offspring
Behavioral isolation
Occurs when 2 individuals are capable of interbreeding but have differences in courtship rituals
Geographical isolation
2 populations are separated by geographical barriers and evolve differently due to the separation
Temporal isolation
occurs when 2 or more species reproduce at different times
Convergent evolution
process of unrelated organisms come to resemble one another
Divergent evolution
accumulation of differences between groups which can lead to formation of a new species
co-evolution
When two species evolve in response to one another
Gene flow
movement of genes into and out of the population (immigration and emmigration)
Genetic drift
when allele frequencies in a population change as a result of random chance, occurs more frequently in small populations
can result in lack of genetic variety and vulnerable to extinction
Hardy- Weinberg
allows scientists to determine if evolution has occurred
for gene frequency equilibrium to occur a population must meet 5 criteria
-no mutations
-no gene flow
-random mating
-population must be large
-no selection can occur
Hardy-Weinberg formulas
p^2 + 2pq + q^2 =1
and
p + q = 1
