Evolution Midterm 2 Modules 10-11

How did John Maynard Smith add to major transitions?

"...there is no theoretical reason to expect evolutionary lineages to increase in complexity with time, and no empirical evidence that they do so.."

Why RNA to DNA?

-DNA molecule is more stable molecule -deoxyribose is less reactive -double strandedness shields from unwanted interactions -DNA replication has proofreading mechanisms absent in RNA replication -can have longer genes which leads to more information and complexity

colinearity

-describes the parallel body plan-chromosome arrangement observed in animals

What were important points of the Davidson and Erwin article in module 10?

-evolutionary inflexible subcircuits called "kernels" perform essential upstream functions in building given body parts -small subcircuits called "plugins' can be coopted to lead to diverse developmental purposes -switches serve as I/O devices to regulate whether or not a subcircuit functions in a given context (can be subject to mutation) -gene batteries are groups of protein coding genes under common regulatory control, the products of which execute cell type-specific functions

Why do symbionts sometimes horizontally transfer genes to the host?

-it can help fix interdependency -may allow for host organism to regulate production

Why did RNA come before DNA?

-present in many of the oldest (slowest evolving) and critical cellular processes--transcription and translation, cofactors --can store and transmit information (and is subject to natural selection) --RNAs can polymerize in the presence of clay (montmorillonite)

What are the pieces of evidence for symbiosis?

-separate, circular genomes -similar cell size to bacteria -independent replication -genes resemble those from bacteria

When did multicellularity occur?

1 billion years ago

What were the six major transitions of life on Earth?

1) molecular replication (ribozymes) 2) information storage and transmission 3) Segregation of 1) and 2) 4) Prokaryotes to Eukaryotes 5) unicellular to multicellular 6) solitary life to multigenerational colonies

Local conditions of disjointed species populations that result in distinctions must...

1) spread via gene flow 2) be advantageous

How does limb development occur?

1. FGF (fibroblast growth factors) - induces formation of AER (Apical Ectodermal Ridge) 2. Limb bud thickens at distal region 3. AER stimulates limb outgrowth to form undifferentiated paddle 4. ZPA (zone of polarizing activity) by action of SHH (Sonic Hedgehog) gradient that determines anterior-posterior identity

How is Evo-Devo studied?

1. morphological study -anatomy -physiology 2. molecular study -gene sequencing -gene cloning -tissue visualization

From how many taxonomic lineages of cells are plant cells derived from?

3

According to Davidson and Erwin, bilaterians emerged _____________ years ago , which is likely when the earliest examples of ___________ evolved and have remained relatively unchanged in since then, even in extant taxa...

630 million years ago; kernels

Who discovered the first ribozymes?

Cech and Altman

Why was compartmentalization important to life developing on Earth?

Compartmentalization of all the necessary components increases the likelihood of more replicative cycles, more quickly. With each replication, new mutations arise, of which those perpetuating good or better replication would be fixed

Punctuated equilibria was proposed by who?

Eldrege and Gould

True or False. All life has a tendency to progress towards greater complexity

False

True or False. Mealybugs harbor only one bacterial symbiont, named Tremblaya, in their bacteriocytes.

False

True or False. HOX genes within a species rapidly acquire and fix mutations each generation to ensure the greatest phenotypic diversity and responsiveness to dynamic external conditions.

False; Hox genes are responsible for large developmental changes. Organisms can only acquire a few of these at a time

True or False. There are several known, extant model groups of organisms that include closely related single and multicellular organisms.

False; very few available for study

Microevolution occurs between species. T/F?

False; within species through variations in allele frequencies Ex) antibiotic resistance

_________ can self assemble to form micelles and vesicles

Fatty acids

What helped fix the relationship between archaebacteria and proteobacteria?

Gene exchange between proto-organelles and nucelus likely helped to 'fix' relationship

contingent irreversibility

Irreversible integration of coreplicating structures, including their information transmission mechanisms, ensures the maintenance of the integration and selection acts on this integrated structure. Because of the division of labor, this results in net fitness increase

What is special about Sulcia?

It can have alternate secondary symbionts

Who asserted that endosymbiosis was a major force in cellular evolution based on their morphological similarities to bacteria?

Lynn Margulis

What duplicated genes were important in plant morphological diversification?

MADS-box genes

What are MADS-box genes?

MADS-box genes are homeotic genes that determine flower organ identity in the Angiosperms (flowering plants) and physiology structure determination

Why do vertebrates have more hometic genes than invertebrates?

More and more duplications allows for more functions to arise especially in cell types which led to diverse tissue types which were more useful to vertebrates than invertebrates

gradualism

New species arise through gradual transformation of ancestral species

gradual evolution

New species developed slowly and at a constant rate over evolutionary history

What did Lamarck propose with regards to complexity?

Scala natura (scale of life) -all life has a tendency to be more complex

evolutionary biology

Study of the changes in organisms over time

Chlamydomonas reinhardtii (unicellular) is closely related to Volvox carteri (multicellular). What is the major difference?

Swimming and reproduction are all handled by a single cell in Chlamydomonas but it has been partitioned into two specialized cells in Volvox

evolutionary developmental biology

The study of developmental biology to shed light on evolutionary dynamics

habitat tracking

The tendency for the geographic range of a species to shift in accordance with changes in the location of its ecological requirements, rather than adapting to environmental changes in its former range.

Eukaryotes/ancient protozoans likely arose from ancient archaebacteria that engulfed but didn't digest an ancient proteobacteria, which then became mitochondria. T/F?

True

Even changing the non-coding regions of weakest pleiotropic effect will increase the likelihood of new variants of bovid mammals. T/F?

True

Macroevolution occurs across species and results in emergence of new species. T/F?

True

Multicellularity is difficult to study. T/F?

True

Speciation can preserve local adaptations when they 'hitchhike' along with other reproductive isolating changes. T/F?

True

True or False. Prokaryotic cells are less complex than eukaryotic cells.

True

True or False. The FGF developmental regulator in chickens has been shown to be capable of stimulating hind limb development in snakes. This suggests that the genes involved in hind limb development in snakes that are regulated by FGF are present.

True

True or False. The cyanobacteria gave rise to an ancestor of plastids found in plant cells

True

True or False: Ancient protozoans engulfed ancient cyanobacteria, which became plastids, and gave rise to first plants

True

True or False: RNAs can self-replicate, cut and elongate oligonucleotides

True

True or False: Small changes in Hox genes can affect large developmental changes

True

How did Volvox evolve from Chladmydomonas?

Volvox has experienced several duplications of genes involved in cell wall biosynthesis and ECM proteins. glsA is required for asymmetrical division in Volvox and it has orthologs in Chlamydomonas. regAis required for somatic and gonidialdifferentiation in Volvox and it has orthologs in Chlamydomonas. -neofunctionalization of glsA along with other modifications (i.e. mutations in other genes, duplications, etc.) gave rise to a new developmental pathway in Volvox --duplication of regA followed by neofunctionalization likely gave rise to rlsD, a close relative of regA, and a new stress-responsive developmental pathway in Volvox

Who proposed that RNA could catalyze reactions?

Woese/Crick/Orgel proposed that RNA could catalyze reactions

Karl Ernst von Baer proposed that the most conserved stages of development among vertebrates are the ________ stages. a) earliest b) latest c) beginning and end d) middle

a

Why are early zygotic traits the most resistant to mutation and change? a) Mutations that alter zygotic development could undo the development of the organism completely. b) Contrary to available evidence, zygotic traits actually acquire mutations quite frequently. c) Post-transcriptional modifications of mutated genes almost always correct these mutations such that they ultimately confer a increase in fitness d) None of the above e) All the above

a

homeobox

a conserved amino acid/DNA sequence within a homeotic gene that regulates development in animals

An ancient ___________ engulfed an ancient _________ which likely gave rise to the earliest ___________ which preceded the earliest ________ cells

archaebacterium; proteobacterium; eukaryote; plant

Of the following, which does not appear to be a consequence of multicellularity? a) division of labor b) reduced irreversible integration c) increased morphological diversity d) specialization of function

b

What evidence supported the endosymbiotic theory of eukaryotic cell evolution? a) The mitochondria produces lactose, which is essential for eukaryotic cells b) mitochondria and chloroplast have DNA similar to that of bacteria c) mitochondria and chloroplast have DNA similar to that of viruses d) Fossils show that eukaryotic cells preceeded prokaryotic cells

b

MADS-box genes affect a) fruit fly development. b) segmentation in animals c) plant leaves, roots, and flowers. d) lateral lines in fish.

c

Which of the following are incorrect statements about irreversible integration? a) each part of the complex structure contribute to overall fitness b) the parts of the complex structure share resources and labor c) the parts of an integrated structure can survive independent of one another d) selection can act on the complex structure/form

c

somatic cells (motile)

cannot divide, keep the body in light

what set the stage for life to arise on earth?

conditions that were favorable for abiotic nucleotide and carbohydrate generation

Identify the incorrect statement a) Ribosomes of comprised of catalytic RNAs b) The Miller-Urey experiment demonstrated abiotic production of amino acids c) RNA could self-assemble/polymerize in the presence of clay/montmorillonite d) The Miller-Urey experiment proves that microbes were responsible for the production of biomolecules on Earth prior to 3.2 billion years ago

d

Biogenetic Law (Haeckel)

developmental progress reflects the evolutionary history of the organisms. Evolution produces new species by appending variation on terminal developmental processes

When organisms get more complex, genes and gene sections within their genome tend to be more what?

duplicated

homeotic genes

encode proteins that regulate expression of genes that determine how cells develop

What gave rise to protocells?

fatty acid-compartmentalized, self-replicating nuclear material, and other necessary components

Why gradual evolution?

fossil record suggests this type of change 1. most organisms have developmental and or genetic constraints 2. stabilizing selection - reduces phenotypic variation and ultimately supports the status quo, which can change but will do so only as external selective factors change 3. evolutionary changes in local populations don't usually contribute to long-term changes

major transitions

fundamental organizational changes in the history of life

From the Davidson and Erwin article, the most frequent and least constrained kinds of evolutionary change will occur within...

gene batteries

What led to distinguishing of chimpanzees and humans?

gene regulation

gonidia (nonmotile)

generate somatic cells and gonidia

______________________ is responsible for the reproduction of both gonidia and somatic cells in Volvox.

gonidium

Describe the Miller-Urey experiment

heated and cooled water vapor + methane + ammonia + hydrogen + electric spark and got amino acids. This was important because originally proteins were thought of as heritable information

orthologs

homologous genes that are in different species

paralogs

homologous genes within a single species that constitute a gene family

Compartmentalization _______ the likelihood that specific replication can occur

increases

Volvocine algae are closely related and display developmental complexity. What do they also display?

irreversible integration

punctuated anagenesis

loss of ancestral state

PAX genes

paired box genes which direct eye development and whose expression is controlled by transcription factors

Kernels act at the ________ -level while differentiation gene batteries act at the ________ -level

phylum; family

Von Baer's Law

related species have very similar early forms and the features that distinguish between different species tend to arise later in development

What is the earliest known catalytic and information transmitting biomolecule?

ribozyme

Hox genes

series of genes that controls the differentiation of cells and tissues in an embryo via coordinating the expression of genes within its 'regulome'

regulatory enhancers

short DNA sequences that bind to transcription factors to increase or decrease likelihood of transcription of a particular gene

what are stasis species? Give examples

species that change relatively little over very long periods of time Ex) cockroaches

changes in coding sequence of major regulatory genes can cause what?

strong pleitropic effects or effects on other genes that they regulate

what is the problem with punctuated equilibria theory?

the absence of fossil evidence to support this

developmental biology

the study of the complete development of an individual from fertilization to death through genetic mechanisms

punctuated evolution

the theory of evolution that proposes that evolutionary changes occur over a relatively quick period of time due to rapid changes external to the organism, followed by periods of little to no evolutionary change

Chlamydomonas are _________ and Volvox are __________

unicellular; multicellular