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53 Cards in this Set

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  • Back
List Charles Darwin's Theory of Evolution
1.Steady Change
3.Common Descent
4.Natural Selection
5.Multiplication of Species
What's Steady Change?
Since the world is steadily changing, species don't stay the same forever.
They adapt to their surroundings
What's Gradualism?
change in the population takes place gradually
What's Common Descent?
There was one single origin of life on earth, and all species on earth had a common ancestor.
Natural Selection (Charles Darwin's Theory of Evolution)
Evolutionary change by the preferential survival and reproduction of organisms (offspring) that are better adapted
Multiplication of species
new species can evolve from existing species
Natural Selection
mechanism by which evolutionary change occurs within a population.

the differential survival and reproduction of better adapted organisms
List Darwin's four observations about natural selection
1. species can overproduce offspring

2.there are limits to population growth- limited amount of food, light, space, and diseases

3. There is variation among individuals- variation can affect one of a number of things, such as the ability to compete for food, or the ability to overcome disease

4. Differential Reproductive Success- Individuals that are more successful are more likely to survive and reproduce. If this variation is heritable, and the better competitors reproduce more, then the offspring of successful competitors will also be successful competitors for resources.
the ability of an individual to produce survivng fertile offspring, relative to other individuals in the population
a heritable trait that increases the fitness of an individual relative to another individual that lacks that trait
Types of Natural Selection
1. Directional
2. Stabilizing
3. Disruptive
4. Sexual
How old is the Earth?
4.6 billion years old
List the four eras of the geological time scale from earliest to latest, and list the approximate years these eras occured between.
Precambrian-4.6 billion years ago to roughly 543 million years ago

Paleozic-543 million years ago to 250 million years ago

Mesozoic- 250 million years to 65 million years ago

Cenozoic- 65 million years ago to the present
What are the steps to the Origin of Life?
Step 1: the abiotic synthesis of complex organic (carbon containing) molecules, such as amino acids or nucleotides

Step 2: The Formation of polymers- synthesizing amino acids and nucleotides (how the chains are formed)

Step 3: The formation of protobionts- macromolecules in solution can spontaniously form liposomes

Step 4: The Origin of hereditary material- probably RNA because:
-it's formed easily
-can replicate itself in the presence of Zn which is in clay
-contains hereditary info
-it is enzymes that do work in biological systems
-simpler than DNA because it has only one strand
What is Life?
life is organized and can reproduce
Sexual selection: Female Choice
Females make their decision by visual cues (usually bright colors) that make their mate seem healthy

ex: peacocks- females like brighter bigger feathers because that means they're healthy

nuptial gifts- spiders usually give nuptual gifts, and the bigger the nuptial gift the better.
Sexual Selection: Male to Male Competition
Males often compete for a chance to reproduce.

Ex: antlers on reindeer

male elephant seals

male lions
Sexual Selection: Female Choice and Male to Male competition
ex. the fruit fly has sex with a variety of males, then later her body determines which sperm she wants to fertilize her eggs.

it's their sperm that is competeing against each other
Sexual Selection points
1.Natural selection produces individuals that are well adapted to their environment. Sexual selection does not necessarily adapt the individual to the environment, but instead enhances traits involved in mate acquisition. Sexual selection can produce individuals with such elaborate ornaments that they must be either energetically costly to develop (a deer’s antlers, for example), costly to maintain, or even lead to a direct survival cost for the individual that bears the ornament In this sense, sexual selection has the capacity to evolve maladaptive traits

2. There's different forms of male and female for the speicies.

3. It's not always male on male competition. Some species, males rear the children, so males get to be choosy.
A change in DNA that makes a mistake in DNA replication. This is heritable.

this creates genetic variance, sometimes mutation can be good because it helps you adapt better with the environment.
sometimes it's bad, and natural selection takes you out of the race because you cannot survive.
Genetic Drift
random process that changes the proportion of the alleles in a population.

Three important points:
1.Genetic drift is random in response to fitness
2.Genetic drift affects small populations the most
3.overtime, it can lead to random loss of alleles

effect on genetic variation: tends to reduce allele variation

effect on average fitness: usually reduces
Gene Flow
movement of genes from one population to another.

When there is gene flow between the populations, it tends to make the two populations similar
Evdience for Evolution
1.There should be evidence for extinction
2.There should be evidence transitional forms in the fossil record. i.e.archaeoptryx
3.If there is common descent, there should be shared genetic info.
4.If there are speciation events, then the animals should be located closely to each other.
5.There should be a difference in natural selection
transition forms
1. it's hard to find fossil records of transition forms because they are so rare.
2.they have been left unchanged due to:
-no good mutation
-same environment
-or not visible changes or living fossils like the coelecanth
Shared common descent
evidence that we are from a common descent
-we all share the central dogma
-all cells have membranes made of lipid bilayers
-we use the same 20 amino acids
-DNA code for protein is unchanged throughout the different species
-basic biochemical pathways are the same in all cells
organisms that look different enough are different species.
similarity due to common ancestry

ex: vertebrates have similar bone structures which indicate that they have a shared common ancestor
similarities between species taht is not due to common ancestry

ex: dolphins and ichthyosaurs- they are similar due to environmental pressure
a group of taxa that contain a common ancestor and all the decendants of that ancestor
more than 2 branches coming from a node
not monophyletic meaning, not all common ancestors are included
Molecular phylogenies
steps 1: line rDNA up (ribosomal DNA)
step 2: see which one is different and then kinda just compare

why do we care?
-can solve difficult questions about species..ex: trying to figure out if guniea pigs are closer to mice or rabbits

-molecular phylogenies can solve difficult questions about broad patterns of evolution..ex: you can't compare humans, mushrooms, bacteria just by looking at them
When was the last mass extinction?
Dinosaurs died about 65 million years ago
Carl Linnaeus
invented the classification system
What are the 5 Kingdoms?
-Monera-prokaryotes- bacteria

-Protists-single celled eukaryotes
List the different Domains

prokaryotes/monera belong in two different domains, either bacteria or Archae. they can have the same kingdom but be in different Domains
What is the Hierarchy of the classification?
Why are Prokaryotes important?
wihtout prokaryotes, many eukaryotes could not survive

-in the beginning, their waste of O2 probably created the air as we know it
How do you catalogue the different Prokaryotes?
Bacteria Culture-to be studied, different bacteria grow in different cultures
ex: strepthroat bacteria only grow in strepthroat culture and etc.. we don't know how to culture everything yet only some

DNA sequence: recently scientists tried to sequence rDNA from the sea and put it on the tree of life!

Shape: spherical (coccus)
rod shaped (bacilli)
screw driver shaped ex: Treponema Pallidum- causes syphillus

Gram Stains- Gram + has peptidoglycan-
turns violet
Gram - peptidoglycan below the cell wall

Gram+ bacteria can be treated with penticillan

Gram- cannot be treated with antibiotics
What's the difference between eubacteria and archaebacteria?
archeabacteria do not contain peptidoglycan in their cell walls
only need CO2 and an energy source, and with that they can make all the nutrients they need

Two types of Autotrophs:
Photoautotrophs and Chemoautotrophs
use light as their source of energy with CO2 to make nutrients

Ex: plants

Important Point: since the byproduct of Photosynthesis is O2, this created free oxygen and gradually became a component of the Earth's atmosphere.
-life as we know it depends on photosynthesis.
in addition to the oxygen rich atomosphere, it is important to evolutionary events.
-plus, things eat photoautotrophs!
gets their energy from hydrogen sulfide and ammonia instead of sunlight.

-in the deep sea

-most of the freeliving bacteria in the deep sea vent communities are archaebacteria

-symbionts in the deep sea vents are eubacteria
relationship between organisms of different species that live together in direct contact

Ex: the tube worms and the bacteria that live inside it.
Mutualistic Symbiosis
When both parties benefit from the symbiosis

EX: the tube worms help the bacteria have a steady flow of water by concentrating hydrogen sulfide and oxygen
the bacteria in return gives the tube worm organic carbon
when the benefit is only with the parasite and deteriment of the host
need a source of organic carbon for food.
two types:
Photoheterotrophs and chemoheterotrophs
capable of capturing energy from light, but they also need a source of organic compounds to survive
ex: they can't make some of the amino acids or something from the light
consume organic componds for both energy and a carbon source

ex: humans.
produces spores by meiosis

diploid multicellular individual
spores/ gametophyte

divide mitotically to generate a multicellular haploid individual

can be male or female or both
what does the gametophyte produce?
gametes which eventually fuses during syngamy
What had to have happen for land plants to survive on land?
-sexual reproduction on land with no water

-ability to survive on land and in contact with air
:needed waxy cuticle layer