Intro to Evolution Flashcards
Endemic
found in a particular area and nowhere else
Evolution
change in allele frequencies of a population across generations
Processes that cause evolution:
- Natural Selection
- Genetic Drift
- Migration (Gene Flow)
- Mutation
Microevolution
Evolution over a short time scale
Macroevolution
Evolution over a long time scale
Nicholas Steno
The first person to recognize that fossils were the remains of organisms (with Shark teeth).
Established Steno’s Law of Superposition- layers of rock are organized in a time sequence.
(1638-1686)
Baron Georges Culver
The first person to recognize extinction.
Said that fossils resemble but are not exactly the same as modern specie and that many past species are extinct.
(Land sloth observation)
(1769-1832)
Homology
The similarity among species due to inheritance from a common ancestor.
There are 3 levels.
Structural Homology
Similarity in adult form
e.g. vertebrate limbs of humans horses, birds, bats, and seals
Developmental Homology
Early in development, distantly related species often have homologous traits that are later lost.
e.g. early embryonic stages of a chick, human, and cat
Genetic Homology
shared gene patterns
Law of Succession
Extinct species were succeeded by similar species
Transitional Species
A trait in a fossil that is intermediate between ancestral (older) and derived (newer) species.
Jean Baptiste de Lamarck
Made the Inheritance of Acquired Traits Theory (INCORRECT): the continuous use of an organ results in its growth (and disuse causes it to shrink)
(1744-1829)
Thomas Malthus
He was a socio-economist.
He wrote the Essay on the principle of Population in 1978. It established the belief of the Malthusian Catastrophe.
(1766-1834)
Malthusian Catastrophe
Without regulation human population size will become too large, leading to famine/war/disease and a population crash back to subsistence levels.
Charles Darwin
Voyage of the Beagle
Collected over 10000 fossils and specimens
Worked tirelessly for 20 years, cataloging his findings, conducting experiments, working on details of his theory.
Published “On the Origin of Species” (1859)
Considered to independently formulate the Theory of Natural Selection along with Wallace
(1809-1882)
Alfred Russel Wallace
Charted the Rio Negro in Brazil Collected specimens Ship catches fire Travled to Malay Archipelago Collects more than 125,000 specimens Redefines biogeography of region Recognizes the "Wallace Line" Wrote theory to explain how species change and new species form Sent it to Darwin Considered to independently formulate the Theory of Natural Selection along with Darwin (1823-1913)
The 4 Postulates of Natural Selection
- Individuals within a population have variation in traits
- Some of that variation is heritable
- Survival and reproductive success is variable
- Individuals best able to survive and reproduce is not a random sample
Heredity
the transmission of genetic characteristic from parents to offsprings
Heritability
the fraction of variation in a trait that
is due to genetic factors
Gregor Mendel
Discovered:
- alleles
- each Gamete carries only one factor
- independent segregation
-dominate and recessive factors
(1822-1884)
Fitness
the ability to survive and reproduce offspring relative to other individuals within the population
Selection pressure
something that reduces the fitness of individuals (abiotic or biotic)
Adaptation
- a heritable trait that increases the relative fitness of an individual in a particular environment
- causes natural selection
Polygenic trait
controlled by multiple genes
Artificial Selection
-deliberate manipulation of fitness by humans through selective breeding
- wildtype corn -> growing the plants that produce max corn -> the corn we have today
- dog breeding
Directional Selection
- changes the average value of a trait
- phenotype higher or lower than mean has highest fitness
- the mean move towards the direction with high fitness
- genetic variation is reduced
Stabilizing Selection
- reduces variation in a trait
- phenotype higher and lower than mean has low fitness
- mean stays the same