Chapter 11 Flashcards
Give a present day example of NATURAL SELECTION
The emergence of the super bug MRSA.
Antibiotics kill the susceptible bacteria and the resistant one alon. The survivors multiply producing a new generation of anti-biotic resistant bacteria.
EVOLUTION
. Genetic change in a population over multiple generations
or
. Descent with modification
Descent with modification
Descent refers to inheritance
modification refers to changes in the inheritable traits over generations
POPULATION
interbreeding members of the same species living in the same place at the same time
When does evolution happen in a population
when some alleles become more common and others less common from one generation to the next.
These changes in alleles account for both the long term and short term changes in the history of life on Earth
What does evolution not answer
how did life begin in the first place
SPECIAL CREATION
The idea that of the sudden appearance of organisms on Earth.
Species were fixed and unchangeable
Earth was relatively young
There could be no extinction
The name of Darwins Ship
The HMS beagle
CONVERGENT EVOLUTION
describes the acquisition of the same biological trait in unrelated lineages.
NATURAL SELECTION
More individuals are produced than survive only those who are able to get the resources were more likely to survive and reproduce
. It occurs when encironmental factors cause the differential reproductive success of individual with a particular phenotype.
ARTIFICIAL SELECTION
when a human chooses one or few desired traits and then allows only the individuals that best expresses those qualities to reproduce
Explain theory of Darwin’s theory natural selection and evolution
His theory of evolution through natural selection
- he observed that individuals in a species are different from one another
- and some of these variations are inheritable
- Competition determines which ones live long enough to reproduce: those with the most adaptive traits would more likely reproduce and pass on thos adptive traits to their offsprings.
- Over many generations natural selectioncoupled with enviromental change or a new habitat could change a populations characteristics or give rise to a new species
MODERN EVOLUTIONARY SYNTHESIS
It suggests that genetic mutations create inheritable variations and that this variation is the raw material upon which natural selection acts
. Mutations are changes in DNA sequence that occur at random in all organisms. Sexual reproduction amplifies the variability by shuffling and reshuffling parental alleles to produce genetically differnt offspringd
The 2 types of biological evolution
1. MICRO EVOLUTION
2. MACROEVOLUTION
Evolution and Alleles
Evolution involves changes in alleles. Because an individual ‘s allele does not change: evolution can occur in a population and not in an individual. Individuals do not Evolve they adapt
MICROEVOLUTION
The relatively short term genetic changes in a population
most common example : Natural Selection
MACROEVOLUTION
large scale events such as the appearance of a new species
ADAPTATIONS
features that provide a selective advantage because they improve an organism’s ability to survive and reproduce.
They are inheritable traits that give an individual a competitive advantage
They include only those structures, behaviors or psychological processes that are inheritable and that contribute to reproductive success
In any population, individuals with the best adaptations are mostlikely to reproduce and pass their advantage to their offspring
Because of this “differential reproductive success” ( natural selection) a population changes over time and the best adaptations to the existing environmentbecome more common with each generation
SELECTIVELY NEUTRAL
some features neither increase or decrease reproductive success ( surviving to be able to have offsprings that also survive)
eg certain phenotypes like the color of ones eye or mutations in silent dna that persist but are not subject to natural selection
REPRODUCTIVE SUCCESS
surviving to be able to have offsprings that also survive)
PHENOTYPE
Is the observable properties of an organism,most of which arise from a combination of environmentalinfluences and the action of multiple genes
How does Natural Selection eliminate phenotypes
By weeding out individuals with poorly adapted phenotypes natural selection indirectly changes allele frequencies in the population
What determines if a phenotype is good
it depends on the environment and time: a trait that is adaptive in one set of circumstances may be a liability in another
Why does evolution never stop
Becauses conditions are always changing