Classes 1-6 Flashcards
Implications of cell theory
common ancestry
what does common ancestry mean
- all single celled individuals are related
- all cells in a multicelllar organism are related and come from preexisting cells
where did the first cells come from?
chemical evolution
describe a double helix structure
two helixes paired with nucleotides between them,, with the two strands running in anti-parallel directions (one side runs 3’ to 5’ and vice versa)
adenine pairs with
thymine
cytosine pairs with
guanine
what is the central dogma?
DNA codes for RNA codes for PROTEINS codes for TRAITS
what is RNA?
aka Ribonucleic acid
- single stranded nucleic acids
- codes for proteins
what is Mrna
RNA molecule that carries the DNA code required for protein synthesis
natural selection acts on… whereas evolution occurs in….
individuals…..populations
what are the two fundamental needs of organisms?
- Chemical energy
- other molecules that can be used as building blocks for DNA, RNA, proteins, and cell membranes
what do organisms use as energy? and what does it do?
ATP or adenosine triphosphate,, it stores and transfers chemical energy
Who were darwin and wallace?
studied evolution and natural selection
what were the 2 theories of darwin and wallace?
1.) Individuals with in a population very in characteristics that are heritable
2.) In a particular environment, certain versions of these heritable traits help individuals survive and reproduce better
what is natural selection?
traits that are beneficial in the current environment are “selected” with in a natural population
what were some of Darwin’s key points in “The Origin of Species
fitness is the ability of an individual to produce viable offspring
and
an adaptation is a trait that increases fitness of an individual in a particular environment
what are the 2 conditions of natural selection?
1) individuals must very in characteristics that are heritable
2) certain versions of these heritable individuals reproduce more
evolution occurs when…
heritable variation leads to differential reproductive success
what was the consensus about evolution before the 1800’s
- species were unrelated and could not change
- the earth was only 6000 years old
- some species were “higher” than others
who were the main theorist of “evolution” before 1800?
plato and aristotle
what did pre 1800’s evolutionary though base itself upon
religion and a higher being,, also a heirarchy
ie) plants were lower than animals were lower than humans
what was the consensus on evolution after 1800?
it was still assumed that all living things appeared out of spontaneous generation, and animals could acquire characteristics that they could then pass on to their offspring, which over time developed into the theory of evolution presented by darwin that we still follow to this day
who were the main evolutionary thinkers post 1800’s
John Baptiste Lamark,, Charles Darwin,, and Wallace
what was Lamarks theory of evolution
- all living things were spontaneously generated
- animals could acquire characteristics that they could then pass to their offspring
what was darwins predictions about evolution?
- species change over time
- all species are related
who was charles darwin
- divinity student
-amateur naturalist - studied in the glapagos and patagonia
what did darwin study in the galapagos?
Darwin studied the different types of bird and tortoise species on the different islands in the Galapagos
what did darwin observe about the different finches in the Galapagos?
each finch had a different beak shape dependent on where they lived and what their diet was
what assumptions did darwin make about the finches based on their differing beaks?
they all must have came from a common ancestor but then diverged along the way making them a slightly different type within the species.
what theory did darwins finches challenge? what theory did it give rise to?
special creation,, descent with modification
what was special creation
the idea that all living things were/are created by a divine being and cannot change bc they are created by a higher power
what is descent with modification?
the idea that all sects within a species have a common ancestor, but over the years the species modifies based on their environments, and therefore separates into new forms within a species.
what author/economist did darwin take heavy inspriation from?
Thomas Malthus
what ideas did thomas malthus contribute to evolutionary thought/natural selection
- “struggle for existence” (more people born than that can survive and there are not enough resources for all. Therefore, those who are best fit to survive will survive and those who aren’t will die off
when did darwin write “the origin of species?”
20 years after his work with the finches
who was wallace?
- working class naturalist
- collected for meuseums and the rich
- worked in brazil
what was some of the work that wallace?
Wallace noted a distinct species split where the amazon river runs through brazil, also noticed the distinct differences in species on the malay archipelago. he denotated the split between austrailian animals and asian animals
what are 3 things the theory of evolution did
1) emphasized the importance of variation and population thinking
2) compiled evidence that species evolve and share common ancestry
3) used geological data and field observation to propose a plausible mechanism for evolution
what are darwins 4 postulates?
1) traits with a population vary
2) some traits are heritable
3) more offspring are produced than can survive
4) individuals with certain traits are more likely to survive and reproduce (aka natural selection)
what is population thinking?
variation is normal and also necessary
evolution by natural selection predicts…
1) species change over time
2) species are related by common ancestry
what did the theory of evolution by natural selection overturn?
1) the idea of special creation
2) changed focus to populations not individuals
3) provides a process for evolutionary change
what is the evidence for special change over time?
geological record,, fossils,, vestigial traits, and homology
why is geological record evidence of change?
we can radiometrically date the earth back 4.6 billion years,, (the 1st bacteria appeared in rocks 3.4 million years ago)
why are fossils evidence of change?
the resemblance of extinct organisms to living ones in the same area suggests descendants.
why are vestigial traits evidence of change?
now useless traits in current species, but they once were helpful to our ancestors which is why we still have remnants of them
why is homology proof of change?
humans share incredible similarities to other organisms such as bone structure and certain embryonic similarities as well which alludes to a common ancestor
what is genetic code homology?
genetic sameness in sequences between two different organisms
what is developmental homology?
sameness in the embryos of two different organisms (ex. gill pouches in human, fish, and chick embryos)
what is structural homology?
sameness in the structures (ie bones) of an organism (ex. the similarities between the fins and arms of humans)
Darwin was the first to propose the idea of evolution (True or false)
False, both lamark and darwins grandfather proposed the idea of evolution before darwin did
is darwin more closely associated with evolution or natural selection?
natural selection
what were the 1st organisms that Darwin bred?
pigeons,, they were easy to manipulate and observe their characteristics from generation to generation
what is artificial selection?
when humans pick and choose characteristics to breed between animals
what were the results of darwins pigeon experiement?
all of the different variations of pigeon could be traced back to one specific pigeon type
what is the summary of darwins 4 postulates?
natural selection occurs when heritable variation leads to differential reproductive success
what happens to “selected” traits from one generation to the next?
they increase in frequency
what is the definition of fitness?
the ability to produce surviving and fertile offspring
what is an example of natural selection among todays population
drug resistance,, tuberculosis outbreak
how did tuberculosis become resistant to antibiotics?
Point mutation- a small mutation in the part of the genetic code that causes it to code for something different
the mutation causes a shape change in the RNA polymerase which causes the drug resitence
summary of the finch experiement
- parents can pass on beak size and shape to their offspring
- during the study a drought occurred and the only food sources that were left were these hard tiny little seeds
- the birds that had the larger beaks to break open the seeds survived and those who didn’t dies off
- then majority of the remaining population had large beaks
what is the principle of segregation?
in order to account for the 3:1 ratio of phenotypes in F2 individuals, it was concluded that two members of each gene pair segregated during the formation of eggs and sperm
what are the 3 principles of predicting genotypes?
1) segregation during meiosis
2) a dominant and recessive allele
3) random fertilization
what are mendels rules?
1) peas have 2 copies of each gene, and may have 2 diff. alleles of each gene
2) genes are particles of inheritance and do not blend
3) each gamete contains one copy of each gene
4) males and females contribute equally
5) some alleles are dominant and others are recessive
what were the early hypothesis of the patterns of transmission of traits?
1) blending inheritance
2) inheritance of acquired characteristics
what was the blending inheritance theory?
believed that traits from a mother and father blend together to form traits in the offspring
- as a result the offspring has characteristics that are intermediate between the mother and father
- theory believed that over time due to the blending variation would becom eobsolete
what is the inheritance of acquired characteristics theory?
traits are modified through use and then passed on from parent to offspring in the modified form
ex) a giraffe extends its neck over time and will pass on said extended neck to the offspring
what is a polymorphic trait?
whenever a trait appears commonly in 2 or more different forms (ex. flower color because the pea plants can have purple or white flowers
what were the details of mendels experiment?
- pea plants have both female and male reproductive organs,, so mendel cut out the male organs of some and used the male organs of others to pollinate the remaining female plants (cross fertilization)
what did mendel study in his expereiment?
phenotypes (flower color, seed shape , seed color, pod color, etc.)
what is a pure line
consists of individuals that produce offspring identical to the parents when crossed with another member of the same pure line, or are self fertilized
why is using pure lines important?
it ensures that when crossbreeding that the appearances of traits are genetically correct, and not just a random event
what is autosomal inheritance?
patterns of inheritance of any genes not on a sex chromosome aka standard patters of inheritance
ex) mendel studies autosomal inheritance
what is a gene?
a hereditary factor that influences a particular trait
ex.) a region of dna in a chromosome that codes for a particular trait
what are alleles?
a particular form of a gene in an individual
ex) the two alleles in a diploid may be the same or different
what is a genotype
a listing of the alleles of a particular gene in an individual,, combo of alleles
ex.) in diploids the genotype lists two alleles of each gene,, in haploid gametes the genotype lists one alleles of each gene
what is a phenotype
an individuals observable traits
what is a hybrid
offspring from from crosses between homo parents with different genotypes
what is a reciprocal cross?
a cross in which the phenotypes of the male and female are reversed and compared with a prior cross
- used to test if the sex of the parent influences transmission of the trait
what is a test cross
a cross of homo recessive individual and individual with the dominant phenotype but unknown genotype
- usually determines whether a parent with a dominant phenotype is homozygous or heterozygous
