Test 1 Flashcards
Homologous genes
genes or a gene sequence that are in different species but encode the same product because the sequence is derived from a common ancestor
closely related species
species that are so similar in appearance that the difference between them can sometimes be unclear.
pseudogenes
inactive genes which are genetic leftovers
homoplasy
organisms that look similar but do not share a common ancestor
biological fitness
success of reproduction and passing these selected traits to offspring
synapomorphy
characteristics shared between different species that have derived from a common ancestor
polymorphism
when there is more than one variant for a phenotype or allele in a population
polyploidy
having more than two haploid sets of chromosomes
replacement mutation
a point mutation that changes a nucleotide and may change the protein to inactive or into something else, seems like a small change but can have great affect
leader sequence
a short sequence that will not be translated, it allows the ribosome to attach and translate the strand
somatic mutation
mutations that cannot be passed to offspring but can cause cancer in the organism which has the mutation
Okazaki fragments
short DNA fragments that are formed on the lagging strand during DNA replication
codon
three base sequences within in the DNA that code for the amino acids in proteins
parsimony
the branching pattern in a phylogenetic tree that requires the smallest number of evolutionary changes
promoter
sequences of DNA in front of the gene that tell RNA polymerase where to start transcribing
evolution
change in frequency of alleles in a population of a species through time
natural selection
the differential survival and reproduction of individuals due to differences in phenotype
homology
similarity between species due to a common ancestor, part may have different functions
shared (common) ancestors
an individual from which all organisms in a certain group have directly descended from
descent
the origin of an inheritance
genes
a DNA segment that encodes a functional product
alleles
different versions of the same gene
Macroevolution
evolution of whole taxonomic groups over long periods of time.
microevolution
change within a species over a short period
speciation
the formation of a new species
Evidence of microevolution
Selective breeding
Direct observation of natural population
Living anatomy: vestigial structures
Evidence of speciation
Lab experiments
Natural populations
Species
Groups that can actually or potentially interbreed but do not breed outside the group
Ring species
Offer particularly compelling evidence that one species can split into two
What does uniformitarianism have to do with evolution?
It paved the way for the geological time scale we use for dating fossils.
What does extinction have to do with evolution?
Extinction of a species and natural selection go hand in hand; therefore, is a major component of progressive evolution. Extinction can be viewed as in Darwin’s eyes, a part of natural selection or as an outcome.
selective breeding
the process by which humans use breeding to selectively develop particular phenotypic traits by choosing which males and females will sexually reproduce
Examples of selective breeding include:
various breeds of domesticated animals/plants, High-runner mice
We directly observe change through time through (textbook example); (Adams’s examples)
Field Mustard; Soapberry Bug and microbes
What are vestigial organs?
organs that appear to be evolutionary leftovers
What is an example of a pseudogene?
CMAH
Examples of vestigial organs include:
tailbone and arrector pili in humans, wings on a brown kiwi, and the spur on the royal python
An example of a ring species is the
three-spined sticklebacks
What is extinction?
the end of a particular group (taxon, species, etc.)
What is succession?
the process of change in the species structure of an ecological community over time
What are fossils?
traces of any type indicating existence of some organism in the past
Can fossils exist of species still living today? If so give an example.
Yes, coelacanth
extinct
no longer in existence
Law of succession
the general pattern of correspondence between fossil and living forms from the same locale
transitional forms
a specie that exhibits traits common to ancestral and derived groups; “missing links”
One argument that has been presented against evolution is the lack of _____. However, the fossil record is littered with the abundant (—-) which is what you would expect with evolution occurring and support for the law of succession.
transitional forms
Evidence of descent with modification is the ___ of all life forms.
relatedness
homologies
Structures shared because of shared genes
descent with modification
the passing on of traits from parent organisms to their offspring
homology
similarity between species that results from inheritance of traits from a common ancestor
In your family whom is most related to whom
brothers and sisters
homoplasies
similar traits in different organisms not due to decent but from convergent evolution
What is an example of convergent evolution?
The wings of a bird and the wings of a butterfly
Convergent evolution
the independent appearance in different lineages of similar derived characters
What is an example of homologous traits?
bones in the adult limbs of different vertebrate species
What three things can provide information on potential homologies?
comparative anatomy, embryology, and molecular biology
anatomy
the structure of an organism
embryology
the development of gametes, fertilization, and development of embryos and fetuses
molecular biology
the structure and function of the macromolecules (e.g., proteins and nucleic acids) essential to life
geologic time scale
a sequence of eons, eras, periods, epochs, and stages that furnishes a chronology of Earth history
radiometric dating
techniques for assigning absolute ages to rock samples, based on the ratio of parent-to-daughter radioactive isotopes present
uniformitarianism
the assumption that processes identical to those at work today are responsible for events that occurred in the past
plate tectonics
a scientific theory that describes the large-scale motion of Earth’s lithosphere
although not natural, indicates that species can change genetic makeup through time based on very specific selective pressures
artificial selection
selective pressures
any phenomena which alters the behavior and fitness of living organisms within a given environment. It is the driving force of evolution and natural selection
Some examples of artificial selection include:
pigeon tail feathers, tomatoes, and Brassica (cauliflower, broccoli, Brussel sprouts, kale, and kohlrabi are all derived form wild cabbage)
natural selection
a short set of postulates and a consequence that follows if the postulates are true; requires a lot of time
Four postulates of natural selection which are all testable
- Individuals in the population are variable
- This variation is genetic
- There is differential survival and reproductive success in the offspring (More offspring are produces than can survive)
- There will be competition for resources/mates and those that have genetic variations to compete most successfully will in turn reproduce the most/pass traits.
The individuals selected for are the individuals ____. Reproduction of natural selection is ____.
most fit. nonrandom.
represents the ability of an organism to pass its genes on to future generations
biological fitness
Natural selection should result in populations that are ________.
better adapted to the current environmental conditions
adaptation
a trait in an organism that increases its fitness relative to other individuals without this particular version of the trait in the current environment
Natural selection acts on individual ____, but the evolutionary consequences alter population _____.
phenotypes, genetic structure
Natural selection cannot instantaneously result in new traits, but new ___ that result in new traits through time.
mutations
Most mutations ____ typically beneficial, but that doesn’t mean that ___ mutations are detrimental.
are not; all
Selection acts on ______, NOT for the good of the ____.
individual, species
_____ is the source of allelic variation and sometimes results in new genes.
Mutation
family tree showing likely evolutionary relationships between organisms
phylogeny
pleisiomorphy
an ancestral (primitive) trait
a derived (descendant) trait
apomorphy
a shared homologous trait that can help define relationships between species
synapomorphy
uniquely derived trait in a single taxon
autapomorphy
any monophyletic group at any level in classification
taxon
an ancestor and all of its descendants
monophyletic group
an ancestor and some, but not all, of its descendants
paraphyletic group
homoplasy/convergent trait
a similar trait that has evolved independently in more than one lineage
when a mutation occurs such that an apomorphic trait reverts to its previous, more pleisiomorphic state
reversal
a of related organisms based on synapomorphic traits; in a phylogeny, this begins at a nodal species and includes all descendants from tat point (in other words a monophyletic group)
clade
a point in the phylogeny representing a divergence between two species from a single ancestor
node
represents a single taxon proceeding through time
branch
represents a unique extant or extinct taxon
tip or terminal node
the two taxa that diverge from the same node in a phylogeny; meaning they are closely related because of a recent ancestor
sister taxa
a node from which three or more taxa seem to arise; this is likely due to not enough character sampling
polytomy
the taxon to which we compare the group of species for which we are trying to construct the phylogeny
outgroup
