EVOULTION - New Matireal for FINAL EXAM

Types of animal interactions

• Predation

• competition,

• herbivory

• Parasitism

• Mutualism

• Amensalism

• Commensalism

Predation

an interaction where one organism (the predator) kills and consumes another organism (the prey).

• Selection acts very strongly on predation, and avoiding predation

Methods of avoiding predation

• Posions

• Signaling

• Tail detachment

• Camoflaoug

• Hard to eat (shell)

• Playing dead

• speed,

• Large group size

Toxins

• A form of avoiding predation

• In order to be affective, it must be signaled you are toxic (and a consistent signal across all memebers of that species)

• ex.) Monach butterflies

Aposematism

Warning coloration (bright signal)

Types of mimicry involed with toxins

• Mulleran mimicry

• Batsien mimicry

Batesian mimicry,

Harmless species mimics harmful or toxic species to avoid predation

• example nonvenomous king snake mimics venomous coral snake;

• Flys that look just like bees

Mullerian mimicry,

Two or more harmful or toxic species share similar warning signals reinforcing predator avoidance

• example bees and wasps share similar yellow black coloration

Arms race

consistent directional selection in the context of two coevolving species

ex.) Venus comb and crabs

Geerat Vermeij

• Blind fossil researcher that Dr. Rutter knew

• Applies his sense of touch to shells in order to determine historical predator prey situations

Rough Skin Newts Arms race example

Newts evolved higher toxcity (TTX Neurotoxin), Gardner snakes evolved more tolerance

Toxins

• Tradeoffs with toxins, as it can affect the host to a degree

• Genetically toxins come from duplications, specilaizations, and alternative splicing

• Neurotoxins evolved independly

Plant defenses to herbivory

• mechanical

  • Spines,Sharp modified leaves that deter herbivores

• Chemical

  • Caffine, nicotine, morphine

• Indirect defense

  • Ants that defend plants from catipillars because the plant provides the ants with food (mutualism)

• When plants are damaged by herbivors, they release chemicals that attrack wasps who may attach the herbivores

High cost of plant defense

• 10% of energy budget goes to defense

• Plants that don’t produce toxin have higher fitness

• Induced defenses only happen after the plant has been attached a damaged

Tolerance

when plants can be partially eaten but maintain fitness

Herbivore offense examples

• Metabolism (can break down plant toxins)

• Sequestration,Herbivores take up plant toxins and store them in their own tissues for defense against predators example monarch caterpillars storing milkweed toxins;

• Galling (Insects make a home inside a plant, and change plant development)

• Trenching - Plants produce a latex substance, and insects cut them to eat it

• Gregorious Feeding - Herbivores feed in groups to overwhelm plant defenses and reduce individual exposure example caterpillars feeding in clusters

Sequestration,

• Herbivores take up plant toxins and store them in their own tissues for defense against predators example monarch caterpillars storing milkweed toxins;

Galling

(Insects make a home inside a plant, and change plant development)

Trenching

Plants produce a latex substance, and insects cut them to eat it

Gregorious Feeding

Herbivores feed in groups to overwhelm plant defenses and reduce individual exposure example caterpillars feeding in clusters

Parasitism

Interaction where one organism (parasite) lives on or in a host and benefits while harming the host without immediately killing it

• Recognition and response is huge for plants protecting against paristism

• Parasites can even control host behavior (last of us)

Virulence

propensity of a parasite to harm of kill the host

Rabbit parasite example

• Overpopulation of rabbits in Austrialia

• Took deadly south american rabbit parasite and brought it to Austrialia

• Kill tons of rabbits, yet today rabbitss till persist highlighting their evolution

Parasite fitness equation

N = # available hosts

Ro = # of new infections produced by host

b = chance virus with infect a host

v = mortality of host due to parasite

d = mortality due to other reasons

r = rate of host overcoming infection

b and v may be coorleated

Modes of parasitic transmission

• horizontal transmission

• vertilcal transmission

Horizontal transmission

• between individual

• typically more deadly

vertical transmission

transmission to offspring

Parasites have ______ with their hosts

congruent phylogenices (they evolve together)

Congruent

similar phylogneies in different groups, usually one is a symbiote or parasite of the other

Less traditional examples of parsistism

• Cuckoo bird becomes foster parents for cow birds eggs

  • The egg mimicry has. evolved through a sex linked gene

Altruism

Behavior where an individual reduces its own fitness to increase the fitness of another individual

• Challenges Darwins theory

Direct fitness

a individuals survival reproduction

Indirect fitness

Relatedness and the fitness from the reproduction of a relative

• amount of relatedness may determine level of altruism

kin selection

traits are favored by increasing indirect fitness

Hamiltons rule —> rb - c > 0

r = coefficent of relatedness

b = benefit to receipient

c = cost to actor

Eusociality,

Highest level of social organization with cooperative brood care overlapping generations and reproductive division of labor where some individuals reproduce and others do not

• Bees

Elements of Eusociality

• Reproduction divison of labor

• overlapping generations

• cooperative care for young

  • Bees have a unique system of relatedness

Monandry,

Mating system where a female mates with only one male

Evolutionary stable stratgies (ESS)

• Strategey that cannot be invaded by another strategey

• that once common in a population cannot be invaded or replaced by an alternative strategy because it yields higher or equal fitness

Tit for tat rules of engagement

• Dont, not cooperate first

• Reliate on those who cheat or betray

• Cooperation after retaliation

Hawk vs Dove (Prisoners Dilema)

• Idea that individuals make binary choices based on costs and benefits

• WIth this, there is game theory that determines which organisms “win” and interaction

Greenbeard effect

an honest signal that indicates cooperation

• A green beard gene does THREE things:

  1. Produces a trait (the “green beard”)

  2. Allows individuals to recognize that trait in others

  3. Causes them to preferentially help those individuals

  → Result: Altruism toward non-relatives that share the gene

• ex.) Slime mold

examples of mutualisms

• Bat and plant species

  • bad gets food, plant gets polinated

• Lichen (alage and fungus)

• Coral and protists

Mutualims require….

extreme unique adaptations and come about through coevolution

Reciprocal parasitism

Interaction where two species exploit each other and each imposes a fitness cost on the other;

• Benefits of being parasitizing must be greater than the costs of being parasitized. Otherwise it is just one way parasitism.

Interactions can fluctuate between mutualism and parasitism often. And exmaple of this…

Yucca and Yucca moth

• Moth lays larave in yucca

• Some moths contribute to polination (mutualism)

• Other moths simply lay larva (parasistism)

  • Theres been an evolution of different speices that act different ways

Cospeciation in mutualism is…

• commmon with symbiotes

  • ex.) Aphids, have bacteria inside them that cospeciated

Senecese

decline in fertility and or surviavability over time

• Kind of interferes with Darwins theory, because why would an organism body every transition to not reporducing, or dying? It decreases fitness

• Organisms like the greeland shark defy this definiton as well

Rate of living hypothesis

• Normal processes leave to ireparable damage

  • transcription, translation, replication etc

  • damage exceeds repair capacity

• Small lived organism have faster metabolisms than long lived organisms

Predictions of “rate of living hypothesis”

1.) Aging rate higher in organisms with high
metabolic rate
2) If repair is maximized: little potential for
selection to increase life span

Stephen Austad

• Aging expert that worked with Lions

Mamalian order related to energy expendture

• Different organism within the mamalian order expend different levels of energy, and usually this is related to metabolism and ultimatley life span (less energy, lower metabolism, longer life span)

• Bats defy this, and have high energy, high metabolism, and relativley high life spans

• There seems to be heritability associated with life span

Telomeres associated with lifespan

Telomeres protect chromosome ends but shorten with each cell division eventually reaching a critical length, and shortening starts to effect actual coding DNA.

ex.) Roundworm experiment showed longer teloemeres coorleates to longer lives

p53 and telomere relatioship

• p53 is a tumor suppressor, and is involved with telemere degradation

• Mutated p53 can limit tumor supression

• But hyperactive p53 can contribute to quicker telemore shorting and therefore quicker death and aging

Evolutionary theory of aging

selection doesn’t favor repair or longer lives. Emphasis on early reproduction

Deleterious mutation hypothesis

If you have a deleterious mutation, but it only affects you later in life, then slection will act on it weakly or neutral.

• Aka these mutations have small selection coefficents

Pleiotrophy

one gene affects multiple traits

Antagonistics pleiotrophy

A gene that has beneficial affects on one trait, has deleterious traits on another

Single genes, and evolutionary changes can do what related to aging

They can influence youthful or elederly traits by allocating energy to reproduction instead of DNA repair

ex.) Opoosoums who live without cars, live alot longer and reproduce later

Mainland opposums priotize early reproduction, and also age faster

Human diseases associated with Plieotrophy

• Huntingtons disease

• Cancer

• Cystic fibrosis

• Alhezimers

menopause

production of eggs/reproductive ability stops

• Maybe be a result of the fact human lifespans have only recently extended

• Or Grandmother hypothesis

Grandmother hypothesis (realted to menopause)

• Study done in orcas

• If kin selection exists, and giving birth later in life is dangerous, then individuals may shift their stratigies to being grandmother style parental care, and still recive indirect fitness

How long ago was the universeve formed

~14 Billion ya

How long ago did the Earth + Solar system Form

~4.5 billion years ago

LUCA

Last universal common ancestor from the 3 domains (bacteria, archea, eukarya)

• 2 Billion years old

Similarties across 3 domains of life:

• All cellular life

• all use proteins (mRNA and amino acids)

• All use DNA templates

• Self replication

Outlier to LUCA

• Viruses

• can be RNA or DNA

• other variation

Ribozyme

A hammerhead ribozyme can catalyze simple chemical reactions while also being an RNA

• Important for understand orgins and RNA world

RNA World

• Theory that RNA dominated the world before LUCA

Evidence supporting RNA World

• RNA is important across 3 domains of life

• It was proven in the lab that Ribozymes could self replicated (2026)

• Miller-Urey Experiment, proved they could create basic amino acids and building blocks under early atmosphere + lightining conditions

• Struggled to produce nucleotides (gap in RNA world)

Asteroid theory

• Earth got hit by a ton of metors

• Murchison Meteorite crashed in Austrilia in 1969

  • Contained amino acids and nucleotides

Panspermia hypothesis

life orgins from meteors

Protocells

Proteins, amino acids, lipids
that can be induced to form
spheres in the lab, also on
Montmorillonite

Prebiotic soup

,Mixture of simple organic molecules in early Earth environments formed from abiotic processes that served as the raw material for the origin of life

• Found on montmorillonite

First orgins of life on Earth

• Around 3.7 to 4 Billion year ago, there is eveidence of iron oxidizing bacteria. Evidence highlighted in graphite, which comes from living organisms

  • There is disagreement about if this is really evidence of life

• 3.26 Billion years ago: Cells discovered in a South African Rock

Prokaryotic Genome

• Distinct from E and A

• Circular chromosomes

• Millions of bases, thousands of genes

• Bigger than viruses, smaller than E

• Efficent, most of genes used for protein coding

• Plasmids can be exchanged between individuals - horizontal gene transfer

Eukaryotic genome

• Nucleous

• Organelles

• Linear chromosomes

• Small % of DNA is protein coding

Barbra McClintock

• Corn research, multicolored kernels

• Chromosome changing in position

• Discoverd transposable elements exist

Stasis,

Long periods where species show little or no evolutionary change;

ex.) Cyanobacteria, stromatolites

Gradualism,

Evolution occurs slowly and continuously over long periods through small changes;

ex) Darwins Evolutionary theory

Punctuated equilibrium

,Evolution is characterized by long periods of stasis interrupted by short bursts of rapid change often during speciation

• Cambrian explosion

Transposable elements

• jumping genes

• Parts of chromosome that ca njump or add to other chromosomes

• 44% of human genome isTE

Class 1 elements

• Transposable elements: retrotransposons

• Use an RNA intermediate

• Reverse transcriptase, integration (similar to HIV)

• Some aruge it is a retrovrius

Retrosequences

,DNA sequences formed when RNA is reverse transcribed and inserted back into the genome often lacking introns and regulatory regions;

Alu elements,

Short repetitive SINE retrotransposons about 300 base pairs long found abundantly in primate genomes that replicate via an RNA intermediate using reverse transcriptase

Class II elements

Class II elements,Transposable elements that move directly as DNA using a cut and paste mechanism mediated by transposase without an RNA intermediate

• example DNA transposons

Consequences of transposable elements

• Methylation, and some small RNA may protect against transposable elements

• Some may be beneficial elements

  • exxon shuffling

  • immun system

Hypothesis for the origin of viruses

• Very limited knowledge

• Hypo 1: Viruses were the first life, and they’re just a pre cellular life relec that has peristed

• Hypo 2: Reduction hypothesis - they are some reduced form of cellular oganisms

• Hypo 3: Escpae hypothesis - part of a cell that managed to remove itself, and diverge independently

• Hypo 4: Viruses initated the 3 domain split, if each domain was initially RNA, and got infected by a DNA virus that transtioned them to DNA (wild theory)

LUCA time range

Somewhere between 2.2 and 4 billion years ago

Eukaryote origin timeline

• 1.8 billion years ago - Empire mine, Michigan shows possible Alage

• Some argue 3 billion years ago - Large archea or Eukaryote found in South Africa, but heavily debated

Cyanobacteria significance,

Photosynthetic bacteria that produced oxygen leading to the Great Oxidation Event which caused extinction of anaerobic organisms and enabled evolution of aerobic and complex life

Ediacaran fossil

• Early signs of multicelluar life

Cambrian explosion

• Huge explosion of animal diversity (520 millon years ago)

• See trilobites appear

• Most animals live on the sea bed at this time, but not all of them

• Its possible that oxygen flucations + Edicaran extinntion could have enabled the exposion

Ediacaran

,Time period about 635 to 541 million years ago marked by the first large multicellular organisms soft bodied and before the Cambrian explosion

Devonian period significane

• 420 - 360 million years ago

• Vertebrates made the transition to land

• Lots of ferns and Forrests of trees

First animals on earth time period

• ~600 million ya (Edicaran)

Permian

299 - 252 mya

• Reptile and Amphibian dominance

• Pangea super continent

• Ended by HUGE permian extinction

Permian extinction

252 mya

• Largest extinction event

• 99% of all organisms died

• Was possibly triggered by huge volcanic eruptions near coal beds

  • This would have triggered CO2 and methane global warming

  • Anoxix oceans —> Sulfide reducing bacteria —> Emissions of toxic sulfied

• Or it could have been a massive metor impact

• Lost of land plants survived

Triassic

251 - 206 MYA

• First dinosaours appear

• Non -dino reptiles are most dominant

• Warm climate, even at poles

Jurrassic Period

206 - 144 MYA

• Dinosaurs dominate

• First birds and mammals appear

• Conifer, fern forrests