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Chapter 17: Population Genetics and Evolution (Evolution and the Origin of…
Chapter 17: Population Genetics and Evolution
Concept
Evolution and formation of Life
Extremely slow process and takes million of years to produce a change
Discovery of Evolution and Natural Selection came around the same time as other critical Discoveries
Population Genetics
Factors that Cause the Gene Pool to Change
Mutation
all genomes are subjected to mutagenic factors
the significant of a mutation depends on the size of the population
Accidents
events to which an organism cannot adapt
Volcano eruptions, floods, droughts
Artificial Selection
which humans purposefully change the allele frequency of a gene pool
GMOs are an example
Natural Selection
The best of the best survive
Does not cause mutations
Factors that Are Not Part of Natural Selection
Purpose, Intention, Planning, or Voluntary Decision Making
Situations in which Natural Selection Does Not Operate
If all the population is genetically identical
Competition does not occur in a habitat
Multiple Selections Pressures
the loss of individuals and reduced reproduction are not caused by a single factor
as the environment changes so does the multiple selection pressures
Botany and Beyond: Species Are Populations, Not Types
Population concept of species
Type concept of species
Need to adapt to where they are
Rates of Evolution
a new species arises in this group once every 500,000 years
evolutionary formation of leaves in seed plants had required over 200 million years
cacti lost their leaves in around 10 million years
Speciation
Phyletic Speciation
Pollen Transfer
each pollen grain carry one full haploid
both birds and insects tend to help pollinate
Movement can be rapid
Seed Dispersal
carried by wind, flood, and stream flow
animals can have seeds stuck to them
Vegetative Propagation
small mobile pieces that reproduce vegetatively
Divergent Speciation
Abiological Reproductive Barriers
Allopatric
Geographic Speciation
nonliving feature that prevents two populations from exchanging genes
Biological Reproductive Barriers
biological phenomenon that prevents successful gene flow
Sympatric Speciation
Adaptive Radiation
Founder Individual
Genetic Drift
Convergent Evolution
two distinct , unrelated species occupy the same or similar habitats, natural selection may favor the same phenotypes in each
Plants and People: Zoos, Botanical Gardens, and Genetic Drift
Endangered species
zoos cause for the animals to be reliant on humans
Botanical gardens are just zoos for plants
Evolution and the Origin of Life
Conditions on Earth Before the Origin of Life
Chemicals Present in the Atmosphere
Second atmosphere
Reducing atmosphere
Hydrogen sulfide, ammonia, methane, and water
Energy Sources
Electricity was abundant on a gigantic scale
water was mainly in the atmosphere
Time Available for the Origin of Life
the time for the chemsynthetic origin of life had no limits
Just a lack of oxygen molecules
Chemical Produced Chemosynthetically
water was boiled and as steam rose it mixed with the atmosphere to acted on by the electrical sparks
all the experiments tell us what is theoretically possible
Formation of Polymers
monomers present in the early ocean had to polymerize if life were to arise
Need a high concentration of monomers
Aggregation and Organization
the possible chemical evolution of life would have been aggregation of chemical components
aggregates are not postulated to have been alive or even to have been early stages of life due to the lack of genetic storage
Early Metabolism
heterotrophs absorbing all material from the ocean and modifying only a few molecules
free molecules would have given that aggregate great advantage over the others
Oxygen
it allows the world to rust
it created conditions that selected for the evolution of aerobic respiration
The Presence of Life
the chemosynthetic theory postulates a long series of slow gradual transitions from completely inorganic compounts to liing bacteria
what is classified as living?