Chapter 13 How Populations Evolve Flashcards
Evolutionary adaptations
Individuals with the best functioning traits are consistently selected
Charles Darwin
Book entitled On the Origin of Species by Means of Natural Selection
Darwin non tradition research
Earth was relatively old and populated by all species being related to each other
Numerous intermediates
Darwins theory
He predicted there were there were lots of intermediaries that existed between species
HMS beagle
Darwin left great Britain on this boat he collected numerous specimens you visited the Galapagos islands
Galapagos species
Resembled those found in South America but showed some variation
Charles Lyell
Geologist who promoted the idea of an ancient earth that strongly influence Darwin
Earth
Darwin was convinced it was very old had been shaped by slow processes and continues to change even today and as the earth changed or revolved the organisms that lived upon it did the same because they responded to their environment
The origin of species
Darwins main points all organisms inhabiting earth today are derived from ancestral species that may have look differently (descent with modification)
the mechanism by which this was accomplished is natural selection
as organisms reproduce they can have a variety of offspring those offspring best fit for their environment are most fit to survive and reproduce
Evidence to support evolution
Fossils
biogeography comparative anatomy and embryology
molecular biology
Fossils
Remnants of organisms that lived in the past that have been turned to stone includes plants animals impressions phones and soft tissue
Sedimentary rock
Were fossilization is most likely
Fossils are often used to compare anatomy of
Extinct organisms with Extant (living) ones
Older, more primitive organisms are found at _______
the bottom
_________, more advanced organisim are at the top
Newer
Fossil records are used to
show that organisms appeared in a historical sequence
Biogeography
the study of the geographic distribution of species
Comparative anatomy
comparison of body structures between different species
Homology
similarity of structures due to common ancestry
Analogy
similarity of structures based on function but DOES NOT share common ancestry
Homologous
two structures that are interpreted as sharing a common ancestor, constructed from the same skeletal elements
Comparative Embryology
the comparison of structures that appear similar during the development of different organisms
common ancestry
during early embryology, some vertebrates look similar, implying they have very similar features, which may indicate ________.
Molecular Biology
used to show evolutionary relationships among species
DNA Sequence
used to determine how distantly (or closely) organisms are related. The more similar = more likely closely related. The less similar = less likely closely related.
98%
similarities between chimpanzee and human
Individual variation
all the individuals in a population have slightly different characteristics. Much of the variation is heritable.
Individuals with less reproductive success die, therefore they do
not reproduce
Only those individuals with traits best suited for their environment, _________, ___________, and ______.
are more likely to survive, reproduce, and leave a greater number of offspring
Natural selection at work
pesticide resistant insects and antibiotic resistant bacteria (MRSA)
population
group of individuals of the same species living in the same area at the same time
population geneticists
investigate the fate of populations as evolutionary units
tracking genetic makeup of populations over time allows us to determine
whether a population is evolving and how fast it is changing.
Mutations are random _______ of an organism.
Changes in DNA
the gene pool
is the collective genome of the population
includes all versions (alleles) of all genes in all individuals making up a population
genotype frequencies can be calculated from allele frequencies using the Hardy Weinburg equilibrium
p2 + 2pq + q2 = 1
p2 = homozygous dominant
2pq = heterozygotes
q2 = homozygous recessive
when the Hardy Weinberg equation is not in equilibrium the allele frequencies continually change over time and the population is undergoing small-scale evolution called _________.
microevolution
homozygous dominant
WW
heterozygote
Ww
homozygous recessive
ww
microevolution
measured by changes in allele frequency in a population
Mechanisms of microevolution
genetic drift, gene flow, mutations, and natural selection
Genetic drift
a change in the gene pool of a small population due to chance
Bottleneck effect
example of genetic drift, results from a drastic reduction in population size and therefore a reduction in genetic variation
Founder effect
genetic drift in a new colony
gene flow
when populations regularly or irregularly exchange genetic material
Mutations
permanent changes in an organism’s genome
relative fitness
the contribution an individual makes to the gene pool of the next generation relative to contributions of others within that population
directional selection
when a phenotype of a population is shifted
favors a more extreme phenotype shifting alleles in a population
disruptive selection
both extremes of the phenotype are favored
stabilizing selection
the variation of a particular trait becomes limited
sexual selection
a form of natural selection in which individuals with certain characteristics are more likely than other individuals to obtain mates
sexual dimorphism
in many animal species, males and females show distinctly different appearances
