module 1 Flashcards
1
Q
What is evolutionayr thinking
A
- Has 2 goals
- how has all life been derived by a single tree
- WHy is there so many different kinds of species
- how did individual species become what they are
- unifying conceptual approach to all sciens
- must be a testable hypothesis
- Must test with empiricle observations made in a lab
- Has always been forward thinking - Their were genetic models making predictions before we had the tech to understand this
2
Q
Why is history impoprtant to evolutionary bio
A
- Trying to find out our own creation
- There are battles between science and religion that contradict
- Science is one way for knowing the universe around us
- Science can cross empiricle evidence so the results can be repeatable and testable
3
Q
What is the unity of life
A
- One tree of life traces back to the origin of all species
- Shows resemblances between related speices
- Many extinction fossils fill gaps 99% of animals that have existed are now extinct
4
Q
How do you interpret an evolutionary tree
A
- Each branch point represents a common acnestory of 2 lineages
- A hatch mark represents a homologous characteristic shared by all groups ot the right of the mark
5
Q
What is homology
A
- Similarities from common ancestors
- Changes in homology best understand change with desceny
- Allows us to make a testable hypothesis
Vestigal - Traits that exist in embryonic forms but dissapear like humans and their tails
Some snakes also have hip bones as their ancestors used to have 4 legs
6
Q
What is convergent evolution
A
- Similar function but they are not related
- The species faced the same challenges and evolved in similar ways but are not ancestrally linked
- Flying squirrle and sugar glider - completely different homologies but function is the same
- Point to a pressure in the environments allowing flying animals to survive
-
* Independent solutions to similar challenges
* Cactus all grow in different deserts but under ismilar conditions. Tend to hoard water and protect it with spines
7
Q
How does knowing homology fill in gaps
A
- analysis of homogous bones in living members and fossils indivcate progression from life on land to a life on sea. Hippos evolved in the other way from whales
- They are not related but share the same ancestor
8
Q
What is biogeography
A
- Some species that resembled one another close enough suggest they ar erelatives were found on different contients
- related to pangea
- and when it split
9
Q
Why is natural selection not a survival of the fittest
A
- 4 testable postulates
Trait variation - traits must vary among individuals
Varation in survival and reproduction (fitness) - Some invidiuals do not reproduce and some will leave significant lineage
Covariation between traits and fitness - SOme traits are inherited more tnan others. Faster offsprings are more likely to survive and pass their informaation on
Inheritance of trait variation - Fast inviduavlas must have offspring who are also fast runners and slow individuals must have offsprings that are slow runners. Allows traits to exhibit heritable variation so it can be passed through evolution
Dogs hvae undergone artifical selection where traits we wanted were breededw ith others
same with vegetables who have been breeded to provide the best nutrition for humans
10
Q
What is natural selection in response to ibtroduced speices
A
- Soap berry bugs feed on fruits.
- one species has a long beakso it can eat seeds of a big fruit
- shorter beaks for ones in areas where the fruit is closer or the seed is closer
- having a long beak would be a disadvantage in that area
11
Q
What are key terms of phenotypic and genetic varation
A
Individual - physiolgically integrates unit that developed from sexually reproduced zygote
In bacteria has been more closely examined because some can clone themselves through sexual reproduction
Population - Genetical people that are indepent of other populations - remain genetically distinct to some extent
Gene pool - Entire collection of alleles at any given time
Species - group of individuals that can sexually reproduce sucessfuly means sexually fertile offspring Asexual spcies challeneg this definition will be exceptions to any definitions
12
Q
What is pehnotypic varation within a species
A
- some may be due to environment - does not constitute raw materials for evolutionary change
- Phenotypic is caused by individuals
13
Q
What are spurces of genetic varation
A
- NEw alleles enter a population through gene flow
- migration of information being traded from different populations
- Mutation - point mutatoon,insertion/deletion/structural changes/duplication of chromosoems and genomes
14
Q
What is incomplete dominance
A
- Red and white alleles
- they can make intermediates that are pink
15
Q
What is continous phenotypic variation
A
- How you increase amount of genetic loci that affect trait the more different classes might affect a trait when talking about incomplete dominance
- Continous variation that is normally distributed
16
Q
What are the factors needed for hardy weinburg equilibrium
A
- No mutations
- Random mating
- No natural selection
- Extremely large popu;ation size
- No gene flow
17
Q
What are challenges for understanding heritability
A
- Relatives often expeirence a shared environment - relatives i nsmae household habe the same activites, same food, causes a strong similiarity for relatives
- Mothers pass on more to their offspring than nuclear genes - They pass mitochrindiral DNA also resources through lactate
- Generally seperating Genetic factors VG from environmental VE
18
Q
What is the cross fostering experiment
A
- Switching parents and their offsprings so like a family swap
- Birds can have a black tie derived fro mcarotenoids in diet and melanin
- FOund no relationship for carotenoids because it is diet
- 52% of the melanin size derived from father
19
Q
What is founder effect
A
- Type of sampling error founded from small groups of colonists that usually come from a large source population
- Reduces the amount adaptation due to the small amount of genetic variability
20
Q
What is a population bottleneck
A
- When a large population suddenly dies and only a few individuals are left remaining
- samell sample of survivors repopulate and influence the available species
- This is population bias
- Can be from industrialzation or hunting animals to extinction
20
Q
What is genetic drift
A
- When individuals in a population make uneven contributions to a population
- Population will leave a generation that is disporportionate
- Since red flowers are able to create offsprings
- allele fluctuations occur randomlu
- EVentually they may go to 0 or 1 depending on how much it is reproruced
- This is the same as walking in a hallway with blindfold on eventually the random steps you will hit a wall on the side
- process of losing or fixing an allele will take much longer in large populations
- bigger populations have lower fluctuations
- At the begging everyone will have that allele at 50% frequency but eventually it will decrease or increase depending on its heritability
21
Q
How does founder effect cause high gene frequencies
A
- Small population
- Low gene pool traits get heritated around and there is little variation in a population
22
Q
How does gene flow mix alleles among populations
A
- Movement of genes a,ong populations
- allows for sucessfuly movement of gamates ore reproeuctively mature invidivudals among populations
23
Q
what is directional phenotypic selection
A
- Certain traits that are heridtable will select for better fitness to an environment
- Called directional selection because nevironment is pushing selection towards one way on a bell curve
24
What is stabilizing selection
* When extremes are reduced and the middle of the bell curve is extended higher
*
25
What is disruptive selection
* Favours variants on both ends of distribution
* Causes the bell curve to split into right and left curves
* IF there are red and blue animals
* Disruptive will deselect intermediates and select for both colours
* This is very rare and selects for the extremities
26
What is sexual selection
* Involves intra sexual and inetr sexual selection
* peakcocks choose the highest ornamented males
* Physical appearance affects the ability of sexual reproduction of animals
27
What are prezygotic barriers
* Prevent mating before they can actually mate
* Habitat isolation
* Temporal isolation - different breeding seasons
* behavioural isolation - species must be able to do certain things to allow breeding
* Mechanical isolation - incompatible equipment
* Gamete isolation two species can mate but they cant form a gamete
28
What are the post zygotic barriers
* Reduced hybrid viability - might be retarded
* Reduced hybrid fertility - cannot reproduce
* Hybrid breakdown - so genetic different they cannot breed with normal individuals
29
What are the 3 phases of speciation
Seperation
Divergence
Reproductive isolation
* Genetic drif will force divergence in populations
* Gene flow will homogenize and make the population similar to one another
* Natural selection - if diverging populations see different selectibe pressure directional selection can choose differewnt traits
30
What are the different kidns of speciation
**Allopatric**
* Species are seperated by geographical means
* barrier is dpeendnt on that species is not the asme for all
**Sympatric**
* Happens without any physical seperation
**dispersal**
* species colonizes different area and founder effect occurs
**Vicariance**
* Migration where a population will diverge from the current species
31
How does seuxal selection drive reproductive isolation
* physical appearance for fish determines sexual partner
* normal light they can tell the species apart - females want theur own species
* under monochromatic ligjt they cannot be told apart
* offpsirngs are viable and fertile shows that sexual selectionw as the main reproductive isolation
32
What is reproeudctive isolation by polyploidy
* starts with an instance of hybridation between 2 diverse species
* union of gametes results in zygote with incoreect number of chromosomes for reproreuction
* Possible for a hybrid to undergo mutation that accidentally creates the correct number of chromosomes making them fertile
33
What are the outcomes of hybridation
**Fusion**
* species can fuse and collapse reprorductive isaoltion
**Stability**
* because hybrids are stable in the environment that theu occur in
**Reinforcement**
* Offsprings are unviable and cannot survive in the environment, They are not selected for. Productuin of hybrids is sttonglu selected against. Environment will prevent selecting for hybrids
* When two species are in sympatry they show a difference in some traits likely decrease hybridization but that difference in absecent in allopatry
34
What is the convergent evolution of venom hemotoxins
* Regardless of their origins they all tend to target and acomplish the same things
35
What is the convergent evolution of neurotoxins
* Unrelated lineages thatsee similar selective pressure
* use different geentic mechanisms but arrive at the same things
36
How is venom delivered
* Snails have a radulla which is a harpoon it reels in the pray
* Can be done through the fangs also in snakes
37
How did venoms evolve
* Crotamines are proteins that are considered the orgin
* sister group of these molecuels are called defensin
* It goes to a large progeny or animals including animals
* Protein that is secretedi n the pancreas is used to tight infection
* Converted in some animals to a venemous protein
* main hypothesis is that there was a gene duplication of this defensiv protein from unequal corssing over
lots of genes create venom
* Crotamine derived from defensin
* BNP protein that relax the heart and slow BP - snakes weaponize it
38
What is the birth and death model for venoms
* Duplication causes the gene to be used for other things than what it was intended for
* Once duplicated the genes can be fuplicated again
* They can also be duplicated to a point of not being functional
* Sometimes venoms can undergo reverse recruitment where the body reuses the gene within the body and leads to the loss of venoms
* They are loss trhough evolutionary means
39
Explain the gain and loss of venom in rattlesnakes
* A speciation event may change the origanism that the snake preys on. This could render their venom useless towards it this speciation evemt
* some toxins will not work very well and be released from the genome
* prey can also develop resistances which will cause toxins to become useless
* eventually they will vestigilized
40
Where did fangs come from
* Co opted form teeth
* These are things that evolve from existing structures
* Early ancestors that are not venemous there are small dented infoldings of the teeth called plicky dentine
* Thing that creates a fang is a bigger infold then the teeth will fill the gap and create a tooth
* all teeth have the evolutioonary capacity to become a fang because they have little infolding in the tooth
41
Why are there so many toxins in a venom
* WHen venoms are lost they are relaxed in selection
* eventually bodys will mutate away from them and degrade the trait
* If there is a cost for that trait it will disappear faster
* some plants that can no longer photosyntheisze like parasites they still have the chloroplasts but they are not functional
42
What are the 2 methods for studying toxins
* Protionic method - Inject venom into the apparatus delute and let it run an HCL -C collimin and will seperate on suze shape and affinity
* This is analyzing the protein itself
* Transcription method - Derives from if you have genome of snake. The genome venoms are what we can see what venoms and precurose the snakes have
43
What is the first life on earth
* Everything starts with organic molecules
* DNA or RNA was first self replicating organic molecule
* progenote - first living organism taht gave life to all organisms
* asserted by it having DNA nucleotides
43
What is the first eukaryote
* Many different early organisms
* Promenant progenote gave rise ot the cocestor
* Evolution is always producing extendedl inages
* Best environment give rise to the best lineage and others will go extinct
* First bacterium arose and many lineages died out
* First archea become multicullular and dound some way to encapsuklate its DNA
* it was able to regulate the nuclear and cytoplasmic environment seperately
44
What was the first multicellular organism
* Endosymbiosis of the bacterium was ableto use oxugen in a different way
* Mightve happened many different ways but the way that we see is the only successful attempt
45
Explain the colonization of land
* Needed to be food on thab to give rise to animal species
* land plants evolved from algae
* early land plants did not go alone, There were fungal partners which later become roots
* Terestrial plants paved the way fro animals
* arthropods made the tranistion first
* then vertebrates
* some terrestrial organisms then returned back to the sea
46
What is the fossil record
* Mineralized for frozen remains of organisms
* biochemical evidence of the organism
* Can be dated with half life of isotopes - half life of carbon is very accurate
* The record is biased - many organisms like plants do not leave good fossils
* sometimes animals do not die in sedementary rock foundations
47
What is contential vicariance
* Allowed lots of allpatric speciation via vicariance
* Tetrapod lineages increased wit hteh seperateion of plate tectonics
* difting of contients changed cooler and warmer temperatures
* Also allowed for speciation
48
What were the mass extinction events
* 5 major mass extinction events\
* asteroid strike also
* involve cascade of abiotic and biotic factors
* volcanos spewerd ash caused global cooling
* also smog would warm temperature
* P emission of posion cause many poor feedbacks
* Humans are considered the 6th great extinction due to the environmental changes we are making
49
What are adaptive radiations
* mass extinctions cause decline of some animals and allow others to explode in speciation
* adaptation raditoons is a group that allows a species to evolve and fill the spaces of extinct animals
* mass extinctions allow other organisms to take their ecological roles
* Can also allow adaptive radiation in other groups. SUch has plants evolving and causing chanegs in other organisms that might feed on them
50
What is evolutionary novelty
* Natural selection can only work with raw materials available to it
* small changes to genes reguklate development can have significant chanegs on parts that might play a role in development
* skulls of chimpanzees and human feetis are similar
* timing to size of changes number of nutrients and hormones can effect the pedomorphisis - when an animal that is sexually mature retains traits from when it was a baby
* Organisms with different arrangements chan have similar genomes
* Humans have all the genomes in flies
* These genes might be expressed differently in different aprts of the body
* if you jave compelx structures of many parts and no single part id advantageous on its own then it could not have evolved through natural selection
* Eye shows a lot of this
* through evolution of eye receptors
* habdful of eyes exist in nature
* chambered and compound
* eyes need a photo receptor and a lense. Lense proteins evolved from photo receptors
* They were coopting a protein from one function to another function
* Have evoled independently several times and have been passed on through common acnestry
51
Why is evolution not goal oriented
* it is not in a straight line
* many lineages have gone extinct we cannot see
* process by which a species persist and others fail is akin to species selection
* no drive to any certain endpoint
52
How does similarity imply recently common acnestry
* Not neccessary sometiems there can be unrelated lineages that develop the same adaptions to the environment
*
53
What are the different kinds of evolutionary trees
**Monophyletic**
* A B C
* all included in a txaonomy grpup becuase they share a common ancestor
**Paraphyletic**
* They share a common acnestor at 2
* G must be included for this to be monophyletic
* Mosy recent common anctesor of all group members is within that group
**Polyphyletic**
* A B C D
* All species share ocmmon acnestor at 3 but are not closely related
* Most recent common ancestor of that hroup is not included in the group
54
How are trees sneaky and arbitrary
* The nodes can be rotyated in any direction
55
How are trees built
* Built from homologous charteristics
* Most characteristics is at the end and the start of the tree is the least characteritics
* Outgroup is animal that has no charactersitics
* Must derive which character traits are ancestral and which are developped more recently
* Hinged frogs are present in 4 groups which show that they evolved from the lancelet
