Bio 315 Exam 1 Iowa State University 2023

Define Scientific Theory.

A widely accepted explanation for a natural phenomenon after extensive and rigorous scientific testing

What is the difference between proximate and ultimate cause?

one is the direct mechanism (how)

the other is the big picture/driving force (why)

What are the large-scale questions of evolutionary biology?

evolution answers the how and why about nature and life

What are key individuals in the history of evolutionary biology?

Darwin, Aristotle, Linnaeus

What was Darwins key insight?

descent with modification, all living organisms can be traced back to a shared common ancestor and change accumulated through natural selection because they offer survival and reproductive advantages

What was Aristotles take on evolution?

he believed species were eternal, immutable and discrete, and morphological characteristics were used to describe a species and variations within species were treated as aberrations around an ideal form of the species

What did Linnaeus contribute the the evolutionary biology history?

he came up with a classification system using taxonomy groups

How were extinct animals able to be related to current species?

fossils were used to relate extinct species to modern/current ones

What did Darwin think about variations within populations?

he explained variations as common and important for survival, not aberrant

What are the key historical ideas of evolutions and how did they lead to the current ideas?

Darwinian Evolution: descent with modification

Aristotle: species were eternal, variations were mistakes

Linnaeus: new way to classify organisms

Hutton and Lyell: uniformitarianism

What were some of the Pre darwin thoughts about evolution?

species never went extinct and adaptations arise through divine intervention

What was a big part of the radical shift in biological though?

the finding of fossils that could represent extinct species and showed that they are descended from shared ancestors

What was Hutton and Lyell known for contributing in evolutionary biology?

they established uniformitarianism which explains that agents of change today have always operated in the past, gradual change, uniform process, long periods of time

What is an example of uniformitarianism?

Erosion by a stream formed what we now know as the grand canyon

What is evolution?

change in heritable traits of populations over generations

What is the difference between mico and macroevolution?

micro = evolution caused by change in frequencies of alleles

macro = evolution above species level

What is evolutionary biology?

field of biology that studeis the evlurtionarty processes that gave rise to the diversity of life and how they shape current future diversity

What are the five key points of Darwinian evolution?

Evolution is the norm, traits change over time

common descent, shared ancestry via tree

gradual change, not a giant leap

populations are the unit, evolution acts on populations not individuals

natural selection, traits seemingly designed are results of selection to match environmental needs

What is Neolamarckism?

theories base on ideas of inheritance of modifications aquired during an organsims lifetime

What is Orthogensis?

theories where variations evolve for directed/fixed goals without the aid of natural slection

What is Mutationist?

Theory based on how new phenotypes can arise by processes of mutations and mutant forms are new species, so natural selection isn't necessary

What did Russell Wallace do in the evolutionary biology history?

he also came up with the idea of natural selection before Darwin decided to publish his book

What was Lamarck's theory?

inheritance of acquired characteristics by nervous fluid (wrong)

What did Darwin think about the units of inheritance?

inheritance resulted in a blend , offspring are intermediates between the parents

What is Gregor Mendel think about units of inheritance?

he believed that traits can be inherited unaltered like particles, variations can persist, in contrast to blending

What is a gene?

sequence of DNA that codes fora. particular protein or RNA molecule

What is a locus?

the position a gene occupies on a chromosome

What is an allele?

one of the alternative forms of a single gene

What did Thomas Morgan do to contribute to the history of evoluationary biolofy>

he conducted an experiment with fruit flies that demonstrated mutation generated new variation in every generation and in every trait

What is the difference between the everyday and scientific usage of the word theory?

one means an idea, where as the other means a model so well supported by data the model is considered a fact

Lynx look a lot like bobcats, but they have much larger hairy paws. If large paws have been naturally selected for in Lynx, then there must be in the paw size among inidividuals that is and lynx with larger paws must have higher _ than lynx with smaller paws.

variation, heritable, fitness

What is synonymous substition?

a change in the codon sequwences that DOES NOT result in a change in the amino acid

What is a nonsynonymous substitution?

a change in the codon sequences that DOES result in a hcange in amino acid

What is a point mutation?

a single base pair changes to a different nucleotide

What is a structual mutation?

a mutation that affects multiple base pairs at once due to structural changes in the DNA

What is a transition change?

a nucleotide change where the type of nucleotide remains the same (purine to purine)

What is a transversion change?

a nucleotide change where the type of nucleotide changes (purine to pyrimidine)

What did Kelvin contribute to the history of evolutionary biology?

he argued the world wasnt old enough for Darwinian evolution to create the diversity of life currently observed

What is the main principle of the modern synthesis?

Adaptive evolution is caused by natural selection acting on a particulate genetic variant

What are the four causes of microevolution?

mutation, natural selection, genetic drift, and gene flow

Define Monophyletic

Pertaining to a group of taxa that consists of a common ancestor and all of its descendants. A monophyletic taxon is equivalent to a clade.

Define Paraphyletic

Pertaining to a group of taxa that consists of a common ancestor and some, but not all, of its descendants.

Define Polyphyletic

pertaining to a group of taxa derived from two or more different ancestors

What is the difference between homology and orthology?

Define Parsimony

principle that the simplest scientific explanations is the most likely one, the most simple phylogenetic tree

Define Paralogs

two or more genes found alike in the same genome that likely arose from gene duplication

Define orthologs

two or more genes very similar in different organisms that are predicted to have same function

Define homologs

A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci.

Define synapomorphy

shared derived character by all members of a clade

What are the predictions of evolution? What evidence is there to test these predictions?

What is a phylogenetic tree?

a graphical way to show the relationships between species, traits, and genes

What is a cladogram?

a branching diagram showing the cladistic relationship between a number of species.

What is a phylogram?

A model used by biologists to represent evolutionary history among species by the amount of genetic difference

What is a chronogram?

indicates the timing of evolutionary events; a phylogenetic tree that explicitly represents evolutionary time through its branch spans

Define Ancestral

conserved in taxa from shared ancestor

Define derived

character that has evolved from the ancestral state, unique to that clade

Define homoplasy

a character shared by a set of species but not present in their common ancestor

What are the three types of homoplasy?

convergence, parallelism, evolutionary reversal

What is evolutionary reversal?

the reversion of a derived character state to its ancestral state

What is Dollo's Law?

evolution is irreversible and a species cannot evolve twice (irreproducible)

What is convergent evolution?

Occurs when similar structures from on different species as adaptations to the same environment.

what is parallel evolution?

two related species that have made similar evolutionary adaptations after their divergence from a common ancestor

What is adaptive radiation?

the diversification of a group of organisms into forms filling different ecological niches.

what are the things needed fro evolution to occur?

What are the differences between selection for and selection of a trait?

How do you determine if a trait is an adaption?

What are some examples of adaptions?

What is fitness?

relative capacity to survive and reproduce compared to others in the populations, measured by reproductive successs

How is natural selection distinct from evolution?

natural selection results in differential fitness from variation among individuals

What are the three summary characteristics of natural selection?

VARIATION: there is variation in traits among members of a species, HERITABILITY: the variation is in part heritable so that individuals resemble their relations more then they resemble unrelated individuals, DIFFERENTIAL FITNESS: different variants leave different numbers of offspring either in immediate or remote generations

selection for

A term used to describe organisms that are selected to survive in their environment because of characteristics giving them an advantage

a selection of

a choice or range of different types of something

What are adaptations?

traits that arises via natural selection because it increases survival and reproduction of individuals that have it, it is INHERITED not acquired

What are different types of adaptations?

structural, behavioral, functional

How can you know if a trait is adaptive?

did it evolve via natural selction? (then probably) Co-opted for adaptive function? (maybe?) Arise through evolutionary process? (probably not) Hitch-hiked with trait that is adaptive? (probably not)

How do we test if a trait is adaptive

the comparitive method and the hypothetico-deductive method

what is the comparative method?

comparing sets of species to test hypotheses on adaptive and other evolutionary processes

What is the hypothetico-deductive method?

testing predictions from hypotheses (if x is the case, then we predict y)

What are the different levels of selection?

gene, organelle, individual, groups within a population, species

What is selfish elements?

genes that are transmitted more than other genes

What is segregation disortion?

heterozygotes get more than 50% of an allele

What are altruistic traits?

those that benefit others, but are bad for the individual

What are altruistic behaviors food for?

they are good for the population and important for when natural selection is acting at the level of the group

What is individual selection?

frequency of genes in the population will be influenced by the effects that genes has on the survival and fertility of individuals carrying it

What is kin selection?

frequency of genes in a population will be influence not only by the effects that genes has on the survival nad fertility of individuals carrying it, but asl by its effects on the fitness of relatives of the individual

What is an example of kin selection?

social behavior in honey bees

What is species selection?

results from a correlation between a character and the extinction or speciation rate, reduces character diversity among species

What are the steps in the central dogma?

DNA-transcription-RNA-translation-protein

What are codons?

a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

What is the wobble position?

The third position on the codon, which may not matter in some cases. Doesn't bond anticodon as tightly as the other two.

What are sources of mutation?

replication errors, environmental effects