BIO EXAM 5

Darwin's two observations of natural selection

#1 Members of a population vary in their inherited traits #2 All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce

Darwin's two inferences of natural selection

#1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals Inference #2: This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

Population is defined as:

A localized group of individuals capable of interbreeding and producing fertile offspring

transform boundary

A plate boundary where two plates move past each other in opposite directions

The text describes natural selection as an editing process rather than a creating process. Which of the following analogies illustrates this aspect of natural selection? A. Your professor accepts the correct answers on your exam and then allows you to retake the questions you missed. B. Your professor allows you to turn in 10 copies of your exam, each with different answers. C. Your professor allows you to take your exam open book. D. Your professor allows you to write the exam.

A. Your professor accepts the correct answers on your exam and then allows you to retake the questions you missed.

vestigial structures

Are little or no importance to organism, but remain from an ancestor.

Microevolution

Change in allele frequencies in a population over generations

Which of the following are homologous A.struts in dragonfly wing and bones in penguin flipper B.struts in dragonfly wing and bones in bat wing C.seal flipper and penguin flipper D.bones in penguin flipper and bones in bat wing

D, B and C are analogous

Transition fossils

Fossils that document evolutionary transition

The four different fields of science support evolution through natural selection

I. The fossil record II. Biogeography III. Homology IV. Direct observations

Darwin made two main observations and two main inferences on natural selection. Which of these is least likely to apply to cases of human-driven artificial selection, such as that for differing traits in dogs?

Observation#2: All species can produce more offspring than their environment can support, and many of these offspring fail to survive and reproduce.

You discover fish living in a cave with no natural light. The fish have no eyes, but they do have eye sockets. Using a Darwinian thought process, which of the following would be the reason for this?

Originally, some fish in the population had eyes and could see, but those without eyes had more acute other senses, allowing them to eat, avoid being eaten, and find a mate more easily. Eventually, those with eyes died before they could pass on their genes and the population changed to those without eyes.

The frequency of genotypes can also be confirmed using a

Punnett square

Take the wing of a bat and the wing of a bird. What structures are homologous, the bones, or the wings of the bat and bird?

The bones of the wings are homologous

Phylogeny

The evolutionary history of a species or group of related species

MRSA infections are occurring at alarming rates. One reason for this could be that people do not finish their antibiotics. Which of the following is the most likely reason that this could lead to something like MRSA?

The first few days of antibiotics kill off the weak bacteria, making people feel better. Then, when people stop taking the antibiotics, the strong bacteria that survived have been selected, breed with one another, and create a stronger 'resistant' population

The rise of antibiotic resistance is because

The frequency of a certain allele is changing within the population

Taxonomy is

The science of classifying and naming organisms -two part latin name is called binomail -first letter is capitalized -organized by heiarchy -each level gets more sepecific

Using the Galápagos finches example, which of the following best explains the Darwinian reason why the insect-eating finch has such a long, narrow beak?

Variation existed in the finch population. Those that naturally had longer, narrower beaks could reach their food more easily, allowing finches with these features to survive and reproduce more often than those that did not.

Peppered moth example

White moths eventually all turned black due to their environment becoming more polluted. The environment was cleaned up and the moths eventually all changed back to being more white because that trait had the highest survival rate

Phylogenetic trees represent

a hypothesis about revolutionary relationships

a branch point is where

a lineage diverges

Darwin's finches are the classic example of

adaptive radiation

A gene pool consists of

all the alleles for all loci in a population #of alleles at one locus = #of individuals x 2

over time, structures become less useful or they will have

alternative purposes

polytomy

an unresolved pattern of divergence

Geologists James Hutton and Charles Lyell perceived that

changes in Earth's surface can result from slow, continuous actions still operating today

Newer rocks contain fossils of more _____ organisms

complex; multicellular ex. vertebre

Relative fitness is the

contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals is it capable of producing offspring? Organism that produces the greater number of offspring is more genetically "fit"

In evolutionary terms, an organism's fitness is measured by its

contribution to the gene pool of the next generation

Genetic variation among individuals is caused by

differences in genes or other DNA sequence

basal taxon

diverges early in the history of a group and originates near the common ancestor of the group

Earth's geography has changed ________ over the last 200 million years because of ____________

drastically; continental drift

Natural selection does not create new traits, but

edits or selects for traits already present in the population.

The Hardy-Weinberg principle provides a theoretical constant of gene variation, that when not held constant from generation to generation, reveals

evolutionary influences

Jean Baptiste de Lamarck

first evolutionist to believe that organisms change over time.

Paleontology is the study of

fossils developed by George Cuvier

Differences in homologous structures can be used to

gauge evolutionary relationships

Some ways we organize phylogenetic genes

genes, DNA, fossils (minimally), Genomics, physical traits, and protein sequences

Phenotypic variation often reflects

genetic variation

fossils also help

geographers piece together Earth's continents into Pangaea

Analogous structures or molecular sequences that evolved independently are also called

homoplasies

Genetic drift describes

how allele frequencies fluctuate unpredictably from one generation to the next

Selective pressures are the force that

influence whether a trait is beneficial

In order for a population to change, there must be

inheritable variation within the population

Phenotype =

inherited genotype + environmental influences

strata

layers of sedimentary rock compressed into layers

Fossils are preserved remains or traces of organisms that

lived in a previous geologic age

Genetic drift tends to reduce genetic variation through _______________, especially in small population

losses of alleles

shared bases in nucleotide sequences that are otherwise very dissimilar are called

molecular homoplasies

In order to determine phylogeny, systematists gather information about

morphology, genes, homology, and biochemistry of the relevant organisms -analogy is not helpful

What is the ultimate source of new heritable variation in populations

mutation (e.g., new alleles from errors in replication/recombination)

Most mutations result in

neutral variation-differences in DNA that do not confer selective advantage or dissadvantage

Hardy-Weinberg equation

p2 + 2pq + q2 = 1

According to the theory of ______________, Earth's surface consists of several rigid layers, called tectonic plates, that move in response to forces acting deep within the planet.

pate tectonics (there are several layers of crust)

Individuals don't evolve, ___________ do.

populations ex. During a drought, large-beaked birds were more likely to crack the remaining large seeds and survive. The finch population evolved, not its individual member

Homologous structures are anatomical resemblances that

represent variations on a structural theme present in a common ancestor but adapted for different uses depending on environment

Since related organisms share many physical traits, it makes sense that they must also

share similar processes to produce and develop those traits

Convergent evolution occurs when

similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineage

Homology

similarity resulting from common ancestry -similar anatomy and morphology but not in function necessarily

Old rocks contain fossils of ___________ life forms

simple

the fossils in a particular stratum provide a glimpse of

some of the organisms that populated Earth at the time that layer formed -erosion reveals deeper strata

Why might you expect organisms that are not closely related to share roughly 25% of their nucleotide sequences?

statistics

The discipline of ________ classifies organisms and determines their evolutionary relationships.

systematics .

Genetic variation as a whole can be quantified by

the average percentage of loci that are heterozygous

Biogeography is the study of

the geographic distributions of organisms

If there are complex structures that are similar between 2 species it is likely that the reason for this is because

the information coded in DNA to produce such structures came from a common ancestor ex. bone composition in human & chimp skull

"Descent with modification" summarized Darwin's perception of

the unity of life

If you were to compare only the external morphological features of these creatures, you might assume

they are descended from a recent common ancestor (internal anatomy, physiology, and reproductive systems are very different)

It's not that bacteria know that they need to mutate, its the fact that

variation is present and the local environment determines which traits will be selected for or selected against in any specific population.

We didn't evolve from chimps, instead...

we just share a common ancestor

The Hardy-Weinberg equation can be used to test

whether a population is evolving

Convergent evolution: an example

-Despite this superficial similarity, the sugar glider, a marsupial, is more closely related to kangaroos than the flying squirrel bc they birth mammals not marsupials -shark vs dolphin: similar body plan, even though a shark is a fish and a dolphin is a mammal -due to development in their environments -Although they evolved independently, from different ancestors, these mammals have adapted to similar environments in similar ways.

ammonite fossils

-Lived in the Jurassic and Cretaceous periods (200 million to 65 million years ago). -They can be found in Cretaceous rocks in southern Oklahoma, so at some point in history Oklahoma was probably underwater

Some of Lamarck's theories

-Organisms change through use and disuse: organisms body parts become longer/smaller depending on use -inheritance of acquired characteristics: an organism can pass on these modifications -Organisms have an innate drive towards greater complexity -Evolution by natural processes

Homologous structures are

-Shared by two or more species that were inherited from a common ancestor. -They can be any heritable traits, including DNA sequences, protein structures, anatomical structures, and behavior patterns.

Soapberry bug experiment

-Soapberry bugs feed most effectively when their beak length is similar to the depth of the seeds within the fruit. -Researchers measured beak length in 2 populations, and then compared this data to museum specimens of bugs living in the same area 35 years previously. -Conclusion: A change in the soapberry bug's food source can result in evolution through natural selection for optimal beak shape.

descent with modification main points

-There is a limit to resources and therefore limits to populations. -Only the fittest can survive. Favorable variations will be selected for. Weaker versions will be outcompeted. -Overall, the stronger variations will persist over weaker in the struggle for existence

convergent evolution

-When superficially similar traits may evolve independently in different lineages. -When species share features because of convergent evolution, we say these are analogous structures.

Natural selection is

-a process in which individuals with favorable inherited traits are more likely to survive and reproduce -Natural selection is the mechanism through which descent with modification works

S. aureus example

-became resistant to penicillin in 1945, two years after this antibiotic was first widely used. It then became resistant to methicillin in 1961, two years after it was first widely used. -antibiotics target specific bacterial development. Penicillin targets cell wall. Bacteria develops mRNA strings that strengthen cell wall and fight antibiotics

pros and cons of phylogenetic species concept

-can learn patterns of evolutionary descent -can not deduce phenotypic similarity (ex. birds more related to crocodiles than crocodiles are to lizards) -can not infer a taxon evolved to what is next to it -does not indicate age of species

Charles Darwin (1809-1882)

-embarked on the Beatle to discover unknown species -observed many examples of adaptations -Ex. different finch traits for the birds on each island, different tortoise shell based on environment

in multicellular organisms, only mutations in cells that produce _________ can be passed to offspring

-gametes -In eukaryotes, the majority of mutations happen in somatic cells so the mutation is not passed along

What causes the plates to move?

-mantel convection = heat transfer -natural disasters are the effects

How can a population get new genetic variation?

-natural selection and sexual selection -mutation and breeding with other populations -genetic drift and reproductive isolation -natural selection and mutation -genetic drift and breeding with other populations

problems with fossils

-not all organisms fossilize well -movement of tectonic plates -erosion -UV rays -Even though fossil evidence is diverse, it is often challenging (or impossible!) to find fossils of transitional forms between groups because of lack of technology

Cons of Lamarck's theories

-not supported by science -traits acquired by use during an organism's life are not inherited in the way Lamarck thought

Fossils

-occur all over the world -support evidence for major organisms -fills in gaps of revolutionary history -oldest fossils are photosynthetic bacteria cells -allow researches to test predictions -fossil record is mostly complete -changes over time -extinctions

Artificial selection

-refers to this human intervention. -Individual offspring are selected for breeding, based on them possessing desired characteristics

Problems with the Hardy-Weinberg equation

-the Hardy-Weinberg equation describes a hypothetical population that is not evolving, but we know that all populations are slowly evolving -Natural populations can evolve at some loci while being in Hardy-Weinberg equilibrium at other loci -Some populations evolve slowly enough that evolution cannot be detected

Relative fitness

-the pool of the next generation, relative to the contributions of other individual -Selection favors phenotypes with the greatest fitness

Which population, is at Hardy-Weinberg equilibrium

0.25, 0.50, 0.25

Darwin explained 3 broad observations about life, what are they?

1. The unity of life 2. The diversity of life 3. The match between organisms and their environment

Over time, if we observe differences from the predicted allele frequency we know that the following could've happened:

1.Mutation 2.Nonrandom mating 3.Selection occurs 4.Gene flow 5.Population decrease

Three main mechanisms contribute to genetic variation

1.Natural selection 2.Genetic drift 3.Genetic flow