GBIO 107 Test 1 Flashcards
(134 cards)
1
Q
Creationism
A
- before evolution, everyone believed along these lines
- god or gods created all things at one time, and they have never changed
- “chain of being”
- “ladder of nature”
2
Q
“Chain of Being”
A
- All tings fit into a chain. If we can find the missing links to see how everything fits into the chain, we’ll discover the meaning of life.
3
Q
“Ladder of Nature”
A
- Life forms were striving to be higher forms in nature
4
Q
Rise of Evolutionary Thought
A
1) Exploration
2) Discovery of Fossils
3) New Ideas (of explanation)
5
Q
1) Exploration
A
- new lands, new things, and instead of answers, more questions
- Biogeography
- Comparative Morphology
6
Q
Biogeography
A
- looking at the frequency and distribution of species on a global level
- as explorers find new species, plants and animals… why are these things here and not over there?
- ex: rhea (South America), ostrich (Africa), Emu (Australia) (not everything fits into the chain)
7
Q
Comparative Morphology
A
- looks at similarities and differences in body plans
8
Q
2) Discovery of Fossils (preserved in sediment over a long time)
A
- stratification (at certain layers they only find certain things)
- extinction (there have been lifeforms that no longer exist. How are we going to fit this in the chain of being and ladder of nature now? How can we explain this?)
9
Q
3) New Ideas (of explanation)
A
1) Catastrophism
2) Lamarckism (or inheritance of acquired characteristics)
3) Uniformitarianism
4) Social Revolution
5) Descent with Modification
10
Q
Catastrophism
A
- God created all things at one time and huge catastrophes wipe out some species. Survivors are modern day species. (Doesn’t explain why we don’t find them at each level).
- Aggassle - God created new species after each catastrophe (not enough catastrophes recorded)
- LeClerc - Survivors are changed by the environment to become the modern day species (nothing to back it up. “I think so”). Before he died, denied ideas out of fear of excommunication. At this time, didn’t believe the earth was old enough for this to happen.
11
Q
Lamarckism (or inheritance of acquired characteristics)
A
- use it or lose it theory.
- if you use that body part every day, it will strengthen and change. If you don’t, it will also change. Your offspring will exhibit those changes. (But people whose lose limbs, don’t have offspring without limbs…)
- But in someways correct, there are bacteria that change and pass on these changes to their offspring
12
Q
Uniformatarianism
A
- theory of uniformity, has to do with geology - looking at the stratification.
- layers are not from catastrophes alone. These layers form naturally by years, seasons.
- *** NOW the earth is millions of years old
- at same time… (social revolution)
13
Q
Social Revolution
A
- Thomas Malthus - paper on poor people and survival saying that poor people don’t survive as well as wealthy people. Comes down to competing for resources (food).
14
Q
Charles Darwin
A
- Goes on a five year boat trip on the “Beagle” as a naturalist around the world. Observes and collects species and writes all of his observations down. Comes home and things about all that he’s seen and read.
- spends about 20 years thinking of all these things before publishing Origin of Species
15
Q
Descent with Modification
A
- Charles Darwin
- idea that generations differ slightly, but over time show huge transformations
- ex: in Argentina found Glypodont sp. (fossil - looks like a giant armadillo, size of VW Bug)
- Galapagos Islands
16
Q
Galápagos Islands
A
- a lot about biogeography and evolution comes from islands
- Darwin studied variations here
- all of these islands had Finches (normal beak, tiny beak, curved beak, long and straight beak)
- also studying resources on islands (Malthus)
17
Q
Origin of the Species
A
- 1850s (Alfred Wallace also came out same idea at the same time, Darwin gets credit because he publishes it)
- theory of Evolution
- series of observations and conclusions
18
Q
theory
A
- has to be tested and supported, but can’t be proven or unproven
19
Q
Series of Observations and Conclusions
A
- observation 1
- observation 2
- conclusion 1
- observation 3
- conclusion 2
- observation 4
- conclusion 3
20
Q
Observation 1
A
- There is potential for rapid reproduction in a population
- ex: morning doves (can breed 5-7 times a year - potential is there)
21
Q
Observation 2
A
- Amount of resources (food and shelter) remain stable/constant and the numbers in a population remain relatively stable.
22
Q
Conclusion 1
A
- Survival Differential Exists
- (not everything that’s born survives… why? not enough food or cover.)
- therefore, must compete for resources
23
Q
Observation 3
A
- Variations Exist (among the same species, an individual can be different/vary in its abilities)
24
Q
Conclusion 2
A
- Those variations can help an individual to survive and reproduce. Leaves more offspring.
25
Observation 4
- Inheritance of variations. Some characteristics passed on to offspring.
26
Conclusion 3
* ** Natural Selection/Theory of Evolution By Natural Selection.
- The individual best suited to its environment due to its variations, survives to reproduce, leaving more offspring with those good variations, therefore changing the overall population over time.
- survival of the fittest. Darwin never said it, we do. The one that adapts the best, survives the best.
27
Adaptations
- Those heritable characteristics that help an individual to survive in its environment.
- *** can be great, or can be a liability
- Long-term adaptations
28
Those heritable characteristics that help an individual to survive in its environment.
- morphological features (shape, size, color - camoflauge, etc.)
- behavioral (fight or flight, tool usage)
- physiological (growth rates, metabolism)
29
Adaptations can be great or can be a liability - EX
- ex: 2006, cave system found in California. New species found that had adapted to that cave system. Some adapted to only one specific room, never lived anywhere else. But what if there's an earthquake and it cracks open? Will all probably die.
30
Long-term adaptations
- like the giraffe (long enough to fight and eat, short enough to reach water)
- *** Evolution does NOT happen to an individual, evolution occurs in populations!
31
Population Genetics Terms
- Population
- Gene
- Allele
- Genotype
- Phenotype
- Population Genetics
- Gene Pool
- Micro- Evolution
32
Population Def
- Group of species that lives in one defined area
| - ex: population of squirrels on campus, population in Louisiana, population in Southeastern region of US.
33
Gene Def
- pieces of DNA - code for traits (found on our chromosomes)
34
Allele Def
- alternate form of the gene (dominant/recessive) B= dominant. b= recessive.
35
Genotype Def
- BB, Bb, bb
36
Phenotype Def
- physical expression (blue eyes, brown eyes, etc.)
| - If B = black and b=white, BB= black, Bb = black, bb = white.
37
Population Genetics Def
- Looks at frequency and distribution of alleles (--> traits --> adaptations) in a population.
38
Gene Pool Def
- sum of all the alleles in a population (want more, not a shallow gene pool [inbreeding] - the deeper, the more alleles there are to choose from)
39
Sources of alleles
1) mutations
2) crossing over (homologous chromosomes cross over/mix to one never before seen in meiosis 1)
3) random alignment (also in meiosis 1, from mother and father randomly split)
4) fertilization (the one sperm and egg randomly combined out of thousands/millions)
40
Microevolution Def
- the small scale changes in allele frequencies in a population over time. (can also be termed to Darwin's natural selection)
- ex: the percentage of blue eyed people today compared to the percentage of blue eyed people the years ago.
41
Testing the Theory of Evolutions
- Hardy-Weinberg Principle (wanted to disprove evolution - easier to disprove than to prove)
- Causes of Evolution
- More Examples of Natural Selection
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Hardy-Weinberg Principle
- wanted to disprove evolution-easier to disprove than to prove
- Never found a population that met these conditions
- further proves theory of evolution. (Does not prove, but does not disprove)
- Opposite of these must be causes of evolution
43
Five conditions of Hardy-Weinberg Principle
1) No Mutations
2) No Gene Flow
3) Population Size
4) Total Random Mating
5) No Natural Selection
44
Causes of Evolution
1) Mutations
2) Gene Flow
3) Genetic Drift and Population Size
4) Preference in Mating
5) Natural Selection
45
Mutations (Causes of Evolution)
- accidental, rare change of DNA
- ** only source for new alleles (can be good, bad, or have no effect at all)
- by itself is NOT evolution
- evolution will not happen without mutations
46
Gene Flow (Causes of Evolution)
- itself is microevolution
- immigration and exportation of individuals in and out of a population
- other important stuff:
- - can spread beneficial/good genes occurred
- - prevents divergence of specis (macro-evolution while causing micro-evolution)
47
Genetic Drift and Population Size (Causes of Evolution)
- the random chance that alleles will drift from 0 --> 1
- happens in all populations (regardless of size)
- see effects in a small population
- A) Population Bottleneck
- B) Founder Effect
48
Population Bottleneck (Genetic Drift)
- a small group removed itself from the main population, only breeds among that goup in breeding (inbreeding)
- 1) reduces genetic variability
- 2) increases of genetic disorders
- ex: Ellis Van Crevald in Amish
- ex: Tay Sachs disease (Jewish and Cajun communities/lazy baby disease)
- ex: blue blood/ royals having to mary royals
49
Preference in Mating (Causes of Evolution)
- not a direct cause of evolution (by itself)
- assortative mating (mates choose mates most like themselves - ex: snow goose in 2 colors, blue and white)
- harem mating (1 male, multiple females)
- sexual selection (ladies' choice, most showy, extravagent, etc., ex: peacock)
50
Natural Selection (Causes of Evolution)
- the individual best adapted suited to its environment survives to reproduce
- the environment does not change the individual
- n.s. acts on the phenotype but is a reflection of the genotype
51
4 forms of Natural Selection
1) Adaptations
2) Competition
3) Predator-Prey Cycle
4) Sexual Selection - Ladies' Choice
52
Adaptations (Natural Selection)
- morphological
- behavioral
- physiological
- the bigger the gene pool, the better chance for adapting
- ex: Great Moa - New Zealand
53
Competition (Natural Selection)
- for food/resources/mates
- highest among same species
- got to have an edge
54
Predator-Prey Cycle (Natural Selection)
- co-evolution of 2 species
| - wolf and deer
55
Sexual Selection (Natural Selection)
- ladies' choice
- choosing the best to them - most extravagant, showiest
- most vigorous/healthy, her offspring have a better chance of survival (point of energy)
56
More Examples of Natural Selection
- Directional Selection
- Stabilizing Selection
- Disruptive Selection
57
Directional Selection
- selects 1 extreme, not the opposite or average
- can change directions
ex: peppered moth, West Nile virus, overtreating with antibiotics (don't kill all - leave the ones that aren't susceptible and then those breed)
58
Stabilizing Selection
- selects the average, not the extremes
- ex: lizards - small, medium, and large. The medium is just large enough to fight for territory but small enough not to be an easy snack. giraffe's average neck - not too long or short)
59
Disruptive Selection
- selects both extremes, not the average
- only in birds and butterflies and only with a varied food source
- blackbellied seed cracker (Africa)
60
Evidence of Evolution
1) Artificial Selection
2) Fossil Records
3) Biogeography
4) Comparative Morphology
5) Embryological (evidence)
6) Biochemistry
61
Artificial Selection (Evidence of Evolution)
- Purposive breeding (if you can do it purposefully, why not?)
- dogs - evolved from wolves. how do we know this? because they can still breed.
- when you breed for what you want, you can also get things you don't want. You may get certain traits - but you may also get health side effects. Mutts are the best dogs - have the largest gene pool.
62
Fossil Records (Evidence of Evolution)
- Goal: complete fossil record
- think they have it for a few thigns (horse...? small woodland browser --> )
- "missing link" = ex: archaeoptery X sp. (link between birds and reptiles. dinosaur with feathers (birds evolved from reptiles) - beak, feathers, wings, teeth. Later found cardioptery - which came first?)
- new theory is that all dinosaurs had feathers
- "living fossil" - things that are alive today that haven't changed much
- ex: sharks, crocodiles. THeir fossils don't look much different. THey didn't have to chance much. Top predators that live in an environment that hasn't chanced much, so they haven't needed to.
63
Biogeography (Evidence of Evolution)
- how come there's this over here and not over there? Frequency of distribution of species on a global level.
- plate tectonics
- pangea theory - at one time, all the plates were together in one giant land mass called pangea (260 mya). Then started to break apart and shift.
- explains emu, ostrich, rhea - theory is they were all together in one population
64
Comparative Morphology (Evidence of Evolution)
- comparing the similarities and differences of the body plans (morphology) - looking at different structures, trying to explain evolution.
- three different structures to look at
65
3 Structures of Comparative Morphology
1) Homologous Structures
2) Analogous Structures
3) Vestigial Structures
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Homologous Structures (comparative morphology)
- same internally, but different look and function
- shows morphological divergence (divergent evolution)
- went down different evolutionary paths, but started from the *same ancestor. diverged to look different and act different over time
- ex: forearm of all vertibrates - ours is still comparable to the structure of the dolphin's fin
67
Analagous Structures (comparative morphology)
- different internally, but look the same and have the same function
- morphological convergence (coming together to look the same) (**convergent evolution)
- coming to it from different paths ** different ancestors (may look the same and act the same)
- ex: wings. (from bat/birds v. insects) internal skeleton v. exoskeleton.
68
Vestigial Structures (comparative morphology)
- leftover pieces and parts that are not being used
- evolutionary baggage (leftovers) from ancestors
- ex: why do humans have tailbones? why are there some whales with ankle bones? why do boa constrictors have hip bones? why do manatees have fingernails? (thought is that they evolved form land animal who dug in the dirt)
- ex: appendix, vampire bats have molar teeth...
69
Embryological (Evidence of Evolution)
- developing embryos
| - vertibrate embryos all go through the same stages/look the same (human, lemur, pig)
70
Biochemestry (Evidence of Evolution)
- the one most people look at today. **the Biggy
- looking at DNA
- breaking thigns apart, looking at the genomes. The more similarities/fewer the differences, the more they are closely related. ex: an ape is closer to a human than a dog is to a human.
- don't get hung up on it - everything they find something new, everything else gets changed/is now wrong. And scientists disagree on which of the above forms of evidence are more critical/accurate. Always looking for something new/connections.
71
Evidence of Evolution but...
- but all of this doesn't fully explain all the species we have. Speciation/microevolution = how we have all these different species ( diversity of the species )
72
Species
- pre-Darwinian term
- Biblical term to describe thigns that look different (for the longest time, that was it) ex: bald eagles different than warblers. But what about fly cathres? five different kinds in Louisiana that all look alike unless you pull the wing out and measure the wing!
- Biological Species Concept
73
Biological Species Concept
- developed by Mayr (used in this class)
- population that evolved along different paths because their alleles don't cross. (No Gene Flow between the populations)
- (two populations of things that could breed but don't, and no genes immigrate).
- potential interbreeding groups remain reproductively isolated
- easy way to define this: species - if 2 things can breed successfully, they are the same species.
- so what is successful breeding then defined as?
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Successful Breeding
- having fertile offspring (ligers, mules, etc., not successful.)
75
Problems of Biological Species Concept
- not perfect, though we use it.
1) what about asexual things (jellyfish, parameces?)
2) hard to tell who is breeding (hard enough to catch two things breeding, but then to also follow their offspring to see if offspring are fertile...)
3) still based on looks
ex: the myrtle warbler and the audobon's warbler are members of the same species. Thought to be different for the longest time (white and yellow necks) until found that where their teritories overlap, breed freely. So we can be wrong! But until there's something different, it's the best we have.
76
Speciation
- process of becoming a new species
- two things must occur:
1) Isolation of populations
2) Genetic Divergence of Population
- that being said, speciation has never actually been seen. We find new species all the time. We think this is how it happens...
- three types of speciation.
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Isolation of Populations (Speciation)
- no gene flow
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Genetic Divergence of Population (Speciation)
- how do you get it? natural selection (adapting/best suited to environment at the time)
- mutation starts (not evolution, but starts process)
- genetic drift (the random thing that an allele will drift from 1 to 0. when do we see the effects of it? in a small population.)
79
Three Types of Speciation
1) Allopatric Speciation (**most believed)
2) Sympatric Speciation
3) Parapatric Speciation (**least believed/likely)
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Allopatric Speciation
- most believed
- geographic isolation (allo=different, patric= fatherland)
- - physically separated populations, different geographies/locations. lots of ways this happens
- genetic divergence (natural selection, mutations, genetic drift, non-random mating, etc.)
81
Sympatric Speciation
- sym = same)
- same place, different ecological niche
- ecological isolation (species can be in the same place, even same pond, but because of nich - different food source, slight habitation need difference - can change.
- ex: frogs in rainforest climb to the tops of the trees and stay up there - thousands of years later, one falls down and is too different than the others. new species.
82
Parapatric Speciation
- least believed/likely
- hybrids and hybrid zones
- species A in one territory, species B on the other side, but territories corss. Where territories cross is where the hybrid zone is. Thought is that in the hybrid zone and only in the hybrid zone. A+B+Cs but Cs can't mate with As and Bs. makes more Cs and only survive in the hybrid zone.
83
on species...
- part of being a species is remaining a species, so must remain reproductively isolated to stay a species. we know this actually happens.
84
Reproductive Isolating Mechanisms
- esist to prevent interbreeding (not inbreeding)
- otherwise, huge waste of time and energy (some only mate once a year or once a lifetime - if waste it on something that doesn't work, defeats purposeful life.)
- two types: Pre-Mating Mechanisms and Post-Mating Mechanisms
85
Pre-Mating Isolating Mechanisms
1) Geographical isolation
2) Ecological Isolationg Mechanisms
3) Temporal Isolating Mechanisms (time)
4) Behavioral Isolating Mechanisms
5) Mechanical Isolating Mechanisms
86
Geographical Isolation (Pre-Mating I.M.)
- separated by a physical barrier (oceans, mountains, rivers, etc.)
- ex: allopatric speciation (thought: what made thems eparate species keeps them separate species)
- but only works when it's there - if put them by each other in a zoo, would they breed again?
87
Ecological I.M. (pre-mating)
- same place - different ecological niche (sympatric speciation)
- ex: WTSP (white throated sparrow) and WCSP (white crowned sparrow) - both about the same size and similar colors and songs. Live near each other. WTSP prefers dense underbrush, WCSP prefers open, grassy areas. Within 300 yards their entire lives, but because in different places, won't breed.
88
Temporal I.M. (time) (pre-mating)
- different breeding seasons
- ex: YTMA 9yellow throated warblers), all of the warblers go down to SA for winter, come up here to breed. YTWA, in early April come to Louisiana (trigger in brain), find a mate and breed. Rest of the warblers wait 'till May (kind of look like them, similar habitats, etc.), so don't interbreed. Some may still be waiting to breed - mistakes happen.
89
Behavioral I.M. (pre-mating)
- elaborate courtship songs and dances - important
- identifies the species (I'm doing the right dance, I'm the one you're looking for)
- also starts and stops breeding behavior (not just important to identify species, but triggers the opposite sex to want to breed/or make them stop wanting to breed)
90
Mechanical I.M. (pre-mating)
- pieces/parts don't fit
91
Post-Mating I.M. (in cases mistakes happen, try to keep from total waste of energy)
1) Gametic Incompatibility
2) Hybrid Inviability
3) Hybrid Infertility
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Gametic Incompatibility
- sperm cannot fertilize the egg (gametes won't go together)
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Hybrid Inviability
- most are naturally aborted (the hybrid just isn't viable, can't make it)
- when they are born, they are not capable/not viable (can't walk or chew gum kind of stuff). Usually only works in captivity. In the wild, literally couldn't fly and carry stuff at same time or sing the song of either parent...
94
Hybrid Infertility
- hybrid born strong and healthy, but sterile from birth. No possibility can reproduce-
- ex: mule (horse + donkey), ligers (lion+tiger)
- not a species, just hybrids
- ligers can only survive in captivity
- tigons can have babies but aren't viable for multiple generations
95
macro =
large scale, speciation
96
micro =
small scale, within species
97
Classification
- Linnaeus system
- Phylogenetics
- Extinctions
98
Linnaeus System
- Linnaeus = father of taxonomy
- Artificial system. Not necessarily correct in the way that things are related. For easy identification
- Taxonomy = binomial system (how we name things) - Genus (capitalized), species (not caps), underlined or italics. In latin. Why latin? Universal language - doesn't change. *** know how to write a scientific name (Quercus sp. = genus, don't know the species)
- Looking at general characteristics
99
Linnaeus System Break Down
* *Domain (new, broadest, 2 types - eu and pro)
- Archae (pro)
- Bacteria (pro)
- Eukarya (eu) (really the only to follow the trail)
- Kingdom (broad
- - Animalia
- - Protista
- - Fungi
- - Plantae
- Phylum
- Class
- Order
- Family
- Genus
- Species (specific)
100
Phylogenetics
- evolutionary relationships
- ancestry (how something evolved from one thing into something else. Showing how things are/how closely they are related.) (Love to use trees... know how to read a tree.
101
Know how to read a tree...
- Common ancestor at the bottom, shows progression over time
- With a lot of branches at once = adaptive radiation (a bunch jumped out at the same time.)
- New discoveries can change them
- what if the lines don't go to the top? Didn't make it, or extinct.
102
Extinctions
- 99. % already extinct
- rate of extinction is increasing
- 2 ways to think about them
103
2 ways to think about extinctions...
1) Mass extinctions
| 2) Solitary extinctions
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Mass Extinctions
- opposite of adaptive radiation
- a whole bunch of things disappearing at once
- have been five so far (dinosaurs?
- don't really know what caused it
- more concerned with the other type
105
Solitary Extinction
- this is the rate that is increasing, bigger concern
- to the point some scientists believe we're entering the 6th mass extinction
- just like there are causes of evolution, there are causes of extinction
106
Causes of Extinction (probably acting together)
1) localized distribution
2) overspecialization
3) organism interaction
4) habitat loss or habitat change
107
Localized Distribution (Causes of Extinction)
- or limited range
- found in few places
- ex: only find Koalas in Australia. What happens if there's a huge tsunami in Australia?
- ex: Louisiana Pearlshell mussel - only 2 streams in LA. Need clean water to breed in... LA streams not known for being that clean. What if both of these streams get dirty at the same time? Go extinct.
108
Overspecialization (Causes of Extinction)
- or overly adapted/adapted too specifically
- spiders in CA caves
- Panda bear - eat bamboo (primarily). Bamboo very indigestible, so have to eat a LOT of it. Forests being cut off and bamboo goes through cycles of die-offs. Starve.
109
Organism Interaction (Causes of Extinction)
- competition for resources (they're limited)
- predator/prey cycle (co-evolution of two species, one has adaptation that forces the other to have a responsive adaptation, and circularly forces each other to continued evolution. If responsive adaptation doesn't happen, causes extinction.
- hybridization (can't reproduce or offspring is very weak)
- ex: red wolf (use to have in LA)
- man: overhunting. Great Moa, Great Auk, Turkeys a success story, passenger pigeon
- carolina parakeet
- pesticides (put pelicans and bald eagles on the list - DDT)
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Habitat Loss or Habitat Chance (Causes of Evoluion)
- The Biggie
- single greatest cause of extinctions today
- deforestation
- land conversion (subdivision, farming)
- urbanization (think Over The Hedge)
- Wetland Loss
- What we've lost (because of habitat loss)
111
Deforestation (Habitat Loss)
- rainforest. has the highest bioiversity of any ecosystem. More things live there than anywhere else. If keep cutting, will get to a point where it won't make it back. It also gives us a 1/3 of the world's oxygen...killing ourselves...
112
Wetland Loss (Habitat Loss)
- levees (river isn't building land, it's taking it away), hurricanes (take away barrier islands - then marsh - etc.), oil spills, salt water intrusion (canals cut for oil pipelines), nutria (eating the marsh out)
- not only lose shrimp, fish, oysters, crawfish, but in LA, lose livelihood.
- have more long-legged waders (birds) than in any other state (in LA)
113
What We've Lost Due to Habitat Loss
northern spotted owls
- ivry billed woodpecker *** if leave with nothing else, know this ***
- las seen in LA. large bird, about 18 in. with large white bill. Adapted to living in old-growth forest (80-199 years) to drill into. And feed off of dying (not dead) trees, because they eat the beetles in the tree. Used to be from Carolina all the way to LA and into Texas. Had already thought to be extinct except for this guy in Tensaw parish. Had to shoot one to bring one in for people to believe him. Tried to study and follow them - but only on that one tract by singer Owned by Singer company - begged them please not to cut the land - but cut them. Then they were gone (in 1930s) ... except that every year, people would still call. IN 1987...
- tonnnssss of mony, tons of tim, tones of people from all over the world - why? just a bird? if we could save the ivory-billed wood pecker, could we save ourselves?
- $50,000 reward if you can find it.
- list of 100 most endangered - grey whale, black footed ferret, philippine crocodile, mountain gorilla, sabertooth tiger, california condor
114
Origin of Life
- Spontaneous Generation
- Pre-Biotic Theory
- Forms of Life
115
Spontaneous Generation
- maggots came from meat, frogs came from rain, etc.
- Disproved by ______, that it was the source, but not that it never happens. There's always an aspect of it - something we can't explain.
- biggest idea on where it came from: Big Bang Theory. Different ones (atoms colliding, star exploding, etc.
- pieces began to cool, forming planets
- crust forms, atmosphere developes
- "atmosphere" rough = gases (Hydrogen, Nitrogen Carbon monoxide and dioxide), but no oxygen, no liquid H2O, very harsh
- continues to cool... water vapor condenses rain, forms oceans, lakes
- did the life come from the water? astroids? spontaneous generation?
- we're going with the pre-biotic theory
116
Pre-Biotic Theory (before life)
- chemical world
- chemicals needed for life already here (in atmosphere, in earth's core/crust)
- ** spark: electrical (lighting), UV, radiation... causes simple organic molecules (spontaneous creation) - think amino acid-type structures, falling down into water bodies, forming primordial soup.
117
Primordial Soup/Ooze
- water full of simple organic molecules
- wave action - clay acts as a catalyst, hooks them together to have large organic organic molecules (wet, dry, wet, dry) (we have fats, polysacharides, proteins, etc.) (happening deep in the mud or under rocks - UV light will kill these)
118
Smallest Form Of Life =
- cell. Must have DNA and membrane. In primordial soup, don't have this yet. Is it even possible, though?
119
Stanley Miller
- 1953 - tests primordial soup theory
- builds chamber, fills with these gases and adds electricity as spark. Gets small organic molecules and says (could have worked), never got large.
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So how do we get DNA?
- what is DNA?
- at a cellular level, tells you who you are and what you're supposed to do.
- needs proteins to act as a catalyst (catch 22 - which came first, protein or DNA? DNA tells cells what proteins to make, but can't do that without the protein to tell the cell with.)
- ribozyme - found in 1980 - RNA that acts as its own catalyst, therefore i doesn't need an outside protein. What's RNA compared to DNA? (RNA single strand, DNA double...)
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RNA v. DNA...
_______
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Still need cell membrane...
- forms like a microsphere
- what is a cell membrane made out of? (bylayer of phospholipids)
- microsphere digests a ribozyme = protocell (very first cell), first life.
- can't prove this theory, but what do we know...
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microsphere=
- a hollow ball of lipids (fats, oils) formed by wave action. (Oil and water don't mix) (What happens when oil is dropped into water? Globs up. Take that and the water is going back and forth, backa nd forth,e vetually they become a ball (microsphere).
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Origin of Life: 3.5 BYA
- 1) Anaerobic Prokaryotes
- 2) Photosynthetic Prokaryotes
- 3) Aerobic Prokaryotes
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Anaerobic Prokaryotes (3.5 BYA)
- fossilized remains, first sign of life
- anaerobic = living without oxygen (not there yet)
- prokaryote = no nucleus, organells, etc. (bacteria, single-cell organisms)
- anaerobic metabolism = low energy, inefficient
- thriving, dominating, getting what they need from environment (hydrogen, sulver gas, etc.)
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Photosynthetic Prokaryotes (3.5 BYA)
- photosynethic = uses sunlight to produce own food
- a little more efficiant (can get more energy because the make their own food)
- change the world **
- O2 is a by-prodouct. Oxygen begins to change the environment and the entire world. Now anaerobic prokaryotes have to hide from free oxygen
- chemical origination of molecules stop (because oxygen kills free organic molecules)
- evolution of a new thing...
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Aerobic Prokaryotes (3.5 BYA)
- next fossilized remains
- aerobic = bacteria that use oxygen
- aerobic metabolism = higher yield of ATP (energy)
- much more efficient. So now these things dominate.
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4) Rise of The Eukaryotes: 1.9 BYA
- how did we go from one to the other?
| - theory of Endosymbiosis
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Theory of Endosymbiosis
- how it went from prokaryote to eukaryote/why?
- endo = internal, symbiotic = to things living together happily
- one large anaerobic prokaryote ingests an aerobic prokaryote
- inefficient, so can't fully digest it
- aerobic bacteria thrives inside, has everything it needs for life - bits of other undigested organisms... starts digesting, ATP, making so much it shared it with the big guy... first mitochondria
- digested a photosynthetic prokaryote, makes sugar, makes so much, happy, can't be eaten by anything else, shares its sugar with the big guy, first chloroplasts... this is how we got eukaryotic cells (cells that have stuff in them)
- in other words, big guy eats the little guy = happy two
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Why We Believe Theory of Endosymbiosis
1) chloroplasts and mitochondria have their own DNA (held onto from when they were their own organisms)
2) living intermediaries
- meaning, there are things that actually live like this today. well, then it could have happened way back then, decided to live together, evolved into one.
- ex: amoeba - doesn't have mitochondria, eat aerobic bacteria but don't digest, produces ATP inside of them, may spit them out, may not.
- ex: coral - hosts single-cell algae. Make ssugar - their food source. Can also spit them out, but most of the time hold onto them.
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5) Rise of Multicellular Organisms: 1.2 BYA
- oldest = algea (can still be single cell today, but first multicellular...seaweed = first example)
- why go from single-celled to multicellular?
- why aren't cells bigger? What happens when get too big? the bigger the cell, the longer it takes to do anything, (get food in, get waste out, etc.) have to stay small to stay efficient.
- if you're a single-cell organism, you can't be eaten more easily. Combat being small without getting bigger...? = Cells work together.
- cells work together: too big to be eaten in one gulp, cells can specialize ex: seaweed (cells on top flatten, float on the watertop, make more photosynthesis/energy)
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6) First Multi-cellular Animals: 600 MYA
- everything before = bacteria and plants
- now things start to happen really quickly
- sponge-like creatures (that no longer exist today)
- adaptive radiation (something happens, causes a bunch of species to pop up - like a habitat destruction, preadtor-prey cycle, etc.)
- fish... to... to.... to...
- but all this happened in water...on land?
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7) Invation of Land
- first thing we saw coming out of water to live on land? = wetland plants
- green plants that evolved out of algae - wetland plants (giant ferns, mosses, etc. think dinosaur movies)
- life gets touch living in wetlands, in colder, dryer habitat s(amazing evolution called pollen), see gymnosperms (pine trees)
- pollen then leads to flowers, fruit (angiosperms = flowering trees)
- insects (what came first, insects or angiosperms because they're codependent on pollen?)
- vertebrates... first vertabrate to crawl out of the water = amphibians 350 may (fossilized records)
- reptiles - dinosaurs?
- birds (________, missing link)
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Order to know...
- Anaerobic Prokaryote
- Photosynthetic Prokaryote
- Aerobic Prokaryote
- Eukaryote
- Algea
- sponge-like creatures
- fish
- wetland plants
- gymnosperms (pine trees)
- angiosperms (flowering trees)
- insects (before or after?)
- vertebrates - first out of water = amphibians
- reptiles
- birds
