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134 Cards in this Set

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Plate Tectonics Evidence (Wegener)
Magnetic anomolies:
reversal of magnetic poles has left magnetic stripes in rock layers deposited and Midatlantic ridge splits mirror image of stripes alternating in magnetic direction because of sea-floor spreading.

Plate boundaries: transform, convergent (mountains), divergent (sea-floor spreading, rifting).

Distribution of species (amount of relatedness shows what order groups we separated, ex. related marsupials live on different continents)

Evidence of original supercontinent: Pangea split into Gondwana (South: Africa, S. America, Australia, Antarctica, Madagascar) and Laurasia during Jurassic period. Similar species are most closely related the more recent their respective landmasses separated
pleistocene overkill hypothesis
overhunting of large animals by humans caused exticntion
Mass extinction
extinction of a large number of species within a short period of time, thought to be due to factors such as a catastrophic environmental change that occurs too rapidly for most species to adapt. Much faster rate than background extinction. Number/diversification of species rebounds afterward. Mass extinctions mark the ends of geological time periods.
Background extinction
ongoing extinction of individual species, normal evolutionary process
Examples of Cause for Mass Extinction
Asteroid impact. Flood basalt event (lava plume from massive volcanism). Sea-level drop.
Dating with isotopes:
once an organism dies, their carbon begins to decay. Measuring ratio of carbon isotopes shows how many half-lives have occurred which tells when organism died.
Abnormally high amounts of iridium have been found in rocks dating to the K-T boundary between the Cretaceous and Tertiary periods (65 million years ago). This has led to a widely held view that an iridium-containing comet struck the Earth at that time, which led to the extinction of the dinosaurs and many other forms of life
5 mass extinctions
Cretaceous 65 - 15 35 + 8
Triassic 208 22 53 80 + 4
Permian 245 51 82 95 + 2
Devonian 367 22 57 83 + 3
Ordovician 439 26 60 85 + 3
Make great fossils. Were around for a very long time before mass extinction during cambrian period.
Modern Extinction Rate
recent historical rate of
vertebrate extinctions is a little
over 7,000 times greater than
the background rate of
extinction. 1,000-10,000 times
more than at any time in the
last 65 million years
Evidence for extinction at k-t boundary
rocks laid down precisely at the K-T boundary contain extraordinary amounts of the metal iridium. iridium is present only in the boundary rocks and therefore was deposited in a single large spike. iridium was scattered worldwide from a cloud of debris that formed as an asteroid struck somewhere on Earth.
Cambrian Explosion
Vast increase in diverse forms of life. Existing small simple organisms diversified and became more complex. Fossils begin to appear
Great Oxygen Catastrophe
Life formed anaerobically. Some organisms did photosynthesis, creating oxygen, which was absorbed by oceans and rock. Eventually excess oxygen accumulated in atmosphere, causing mass extinction of anaerobic organisms, creation of ozone layer. Probably caused by photosynthetic cyanobacteria.
c3 and c4 grasses
2 types of carbon fixation used in plants. When the environment turned hot and dry, grasses went from being c3 to c4 to be more efficient (switched to an enzyme with less affinity to oxygen). Only opened stomates at night to reduce water loss. Horses co-evolved to have longer teeth that would hold up to the harder material of the c4 plants.
Cambrian Period
542 - 488 million years ago. Vast increase in life forms.
3 processes changed atmosphere
Volcanos - bulk of the atmosphere was derived from degassing of mantle early in the Earth's history

Chemical Reactions - creation of ozone layer

Photosynthesis - Great Oxygen Catastrophe
Ozone Layer
Created during Great Oxygen Catastrophe, essential to life because protects from harmful UV radiation
Characteristics of Life
Cell Structure


Accurate Replication
Miller-Urey Experiment
Created basic building blocks of life under known conditions of early earth. Chemical reactions that synthesized organic compounds (amino acids) from inorganic precursors.
The Central Dogma
(DNA > replication > )DNA - transcription > RNA > translation > PROTEIN. Only in special situations does RNA turn to RNA/DNA or DNA turn to PROTEIN. Protein can never be transferred into anything else.
Primordial Soup Hypothesis
A liquid rich in organic compounds and providing favorable conditions for the emergence and growth of life forms. Oceans of primordial soup are thought to have covered the Earth during the Precambrian Eon billions of years ago. The organic compounds in the primordial soup, such as amino acids, may have been produced by reactions in the Earth's early atmosphere, which was probably rich in methane and ammonia. The complex self-replicating organic molecules that were the precursors to life on Earth may have developed in this primordial soup.
Prebiotic Molecule
A molecule that is believed to be involved in the processes leading to the origin of life.
eats other things
makes its own food
one of three types of hoizontal gene transfer, transfer of genetic material between two bacterial cells in direct contact
one of three types of horizontal gene transfer, change in genetic makeup resulting from the direct uptake of exogenous DNA from its surrounding and taken up through the cell membrane
one of three processes of horizontal gene transfer, process by which DNA is transferred from one bacterium to another by a virus. injection of foreign DNA by a bacteriophage into the host.
horizontal gene transfer
processes by which exogenous genetic material may be introduced into bacterial cell (transformation, transduction, conjugation)
3 domains of organisms
eukarya, archea, bacteria
phylogeny (2 types)
evolutionary development of a species (reticulate and divergent)
reticulate phylogeny
complicated net of species, happens when there can be horizontal gene transfer, can be found in archea and bacteria
divergent phylogeny
tree like evolutionary history of species
a type of symbiosis in which one organism lives inside the other, the two typically behaving as a single organism. (this led to mitochondria and chloroplasts becoming organelles)
Primary endosymbiosis
involves the engulfment of a bacterium by another free living organism.
Secondary endosymbiosis
occurs when the product of primary endosymbiosis is itself engulfed and retained by another free living eukaryote
Evidence of bacterial origin of mitochondria and chloroplasts
Have 2 or more plasma membranes

Have own genome, replicate separately from host, single circular model, no histones associated with dna

Have own protein synthesizing material

Some genes transferred to nucleus
organisms that engulf solid material with cell membrane to digest
organisms who use the uptake of dissolved organic compounds by osmosis for nutrition
unicellular organism with no nucleus (bacteria and archea)
Bacteria and Archaea that can live and thrive in environments with extreme conditions such as high or low temperatures and pH levels, high salt concentrations, and high pressure.
The process by which a body of water becomes excessively rich in dissolved nutrients, resulting in increased primary productivity that often leads to a deficiency in dissolved oxygen. excessive plant growth and decay, favouring simple algae and plankton over other more complicated plants, and causes a severe reduction in water quality.
PCR (polymerase chain reaction)
Laboratory technique used to make numerous copies of specific DNA segments quickly and accurately
Xenologous genes
homologous due to horizontal gene transfer
What allows for the development of antibiotic resistance?
Lateral/Horizontal gene transfer (prokaryotes)
biological agent that causes disease in a host
Method of gene preservation. Dormant form of bacteria which can withstand harsh environmental conditions for long periods of time in order to continue the species once conditions are favorable again
Endosymbiosis: Vertical Transmission
Passed from parent to offspring
Endosymbiosis: Horizontal Transmission
Found in environment
Endosymbiosis: Mixture of horizontal and vertical transmission
Passed from other members of species
symbiosis where both parties benefit. This is how Chloroplasts and Mitochondria became cellular organelles.
Multicellulatiry benefits
1) Staying in one place and living in currents (being able to feed in currents, like a stream)
2) Can move where they want and more quickly
3) Can eat larger prey and escape predation
4) Cells can specialize (muscles, digestion, brain…)
Multicellularity problems
basal metabolic rate and flux will limit cell size
diffusion is slow
large cells have greater metabolic needs
cooperation(from kin selection)
larger means need for circulatory system then circulatory tissue
increased food demand
How is a multicellular colony different that a multicellular individual?
Individual: once you get germ-soma differentiation
Fick's law
flux = -(permeability of a membrane)(area)(concentration gradient)
Basal metabolic rate
minimum energy production for a cell to survive
A synapomorphy is a shared trait found among two or more taxa and their most recent common ancestor, whose ancestor in turn does not possess the trait.
Colony vs Individual
Individual once there is germ-soma differentiation
germline sequestration
reduces mutation rate because of mitotic arrest, metabloic inactivity reduces oxidative activity
Porifera and how they cope with diffusion time and rate
"Pore bearer." Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes using specialized cells, and the shapes of their bodies are adapted to maximize the efficiency of the water flow. (SPONGES)
Platyhelminthes and how they cope with diffusion rate and time
Exchange gases elusively by diffusion. This explains their flat shape to maximize surface area. (FLATWORMS!)
start with this species to build a cladogram
Monophyletic group
group with common descent from one ancestor
Paraphyletic group
group containing a common ancestor but leaving out some descendents
the division of some animal and plant body plans into a series of repetitive segments.
The evolutionary process that changes a segmented organism into 3 main specialized segments (Head, thorax, abdomen) by fusing and modifying segments
Radial symmetry
no sides, just top and bottom. if cut like a pie, the slices would be identical. (anemone, jellyfish, sea stars)
Bilateral symmetry
symmetrical about line down the middle. left and right sides are mirror image.
no body cavity. semi-solid tissue holds organs in place.
fully functional, partly lined with mesoderm body cavity. Organs are held in place loosely, they are not as well organized as in a coelomate. All pseudocoelomates are protostomes.
fluid filled body cavity with complete lining with mesoderm. allows organs to be attached to each other so that they can be suspended in a particular order while still being able to move freely within the cavity. Most bilateral animals, including all the vertebrates, are coelomates
Blind gut
digestive cavity having only one opening
Compete gut
digestive cavity with 2 openings: mouth and anus
Blastopore becomes mouth.
Spiral/determinate Cleavage: fate of cells determined as they are produced. (asymmetrical cell division: cell creates 2 daughters with 2 different fates)
Blastopore becomes anus.
Radial/Indeterminate Cleavage: fate of cells is undetermined through 8-cell stage, each contain enough information to build complete organism. (symmetrical cell division: cell creates 2 daughters with equivalent fates)
a condition of the blastula in which there are two primary germ layers: the ectoderm and endoderm. The endoderm allows them to develop true tissue, including tissue associated with the gut and associated glands. The ectoderm gives rise to the epidermis, the nervous tissue, and if present, nephridia. (cnidaria and ctenophora)
more complex animals than diploblasts (from flat worms to humans) are triploblastic with three germ layers (a mesoderm as well as ectoderm and endoderm). The mesoderm allows them to develop true organs.
cell has the capacity to form an entire organism of differentiated cells
dormant with no water (form of diapause)
3 domains
eukarya, archea, bacteria
A eukaryotic kingdom: Animalia. Also known as...
sphere of cells that is early form of embryo
stage after blastula, layered sac with endoderm, exoderm, and mesoderm. connects to outside by blastopore.
in a gastrula, connects archenteron to outside.
inside cavity of gastrula that will become the gut
needs to live on land
Ability to breath; must internalize lungs (initially swim bladders)
Structural support
Storage hypothesis
Jointed appendages
complete metamorphosis in life cycle
incomplete metamorphasis in life cycle
egg has everything for offspring except oxygen. mammals, hard egg laying things.
closest membrane to embryo
outermost membrane of egg, shell
nutrient rich cells for food for young in egg
amphibian egg
gelatinous covering, laid in water, gas exchange by diffusion
lay eggs with little or no embryonic development within mother
embryo develops inside mother, nourished by mother not yolk (humans!)
egg remaind in mother until hatch or about to hatch, still gets nourishment from yolk
Characteristics of mammals
Female lactation
Sweat glands
Fur, hair
3 inner ear bones
Neocortex region of the brain
3 types of mammals
Eutheria (placental mammals)
Marsupials (
3 species only, all live in australia: platypus
Egg laying, hold on belly until hatch, then baby sits in fold of skins where mothers pores secret nourishment
Young climb up right after born, milk secreting glands in pouch
placental mammals
Union of embryonic and maternal tissues

Placentas lack yolk but retain chorion and amnion
reliant on maternal milk... probably evolved into placenta
terrestrial egg
Water repellant covering but permeable to gases but not to water
preadaptations to life on land
Gills interanalized
Bones created
cartilage evolved into bone, maybe as storage device for calcium
no true tissues organs or symmetry, sponges, suspension feeders, hemaphrodites, have choamocytes (flagellated cells which creat flow of water through poresto bring nutrients and oxygen)
radial symmetry, diploblastic, have nematocysts (stinging cells used to spear prey)
in porifera, flagellated cells which creat flow of water through poresto bring nutrients and oxygen
in cnidaria: stinging cells used to spear prey
acoelomate, can grow whole self from piece, flatworms, incomplete digestion
pseudocoelomate, round worms, growth by molting
coelomate, deuterosome, water vascular system (tube feet:used for feeding, pulling apart shells, moving), (starfish, sea cucumbers, brittle stars), radial symmetry but larva have bilateral symmetry, adults have endoskeleton of calcium carbonate
water vascular system
in echinodermata: tube feet:used for feeding, pulling apart shells, moving)
deuterosome development, Notochord (structural support-vertabrae), Dorsal hollow nerve chord (ends in brain), Pharyngeal slits in some (pumps water through body filtering out food), 3 subphyla: urochordata(no head), cephalochordata, craniata)
protosome development, mantle tissue which often grows shell, (snails, slugs, mussles, octopus), 3 body parts: mantle(dorsal body wall), muscular foot (contains balance organ and grips things), visceral mass contains internal organs
protosome development, segmentation, no jointed appendages, segmented worms
protosome development, specialized segmentation> tagmosis, jointed appendages, exoskeleton of cuticle, 3 big groups: crustacea, insecta, chelicerata
clonal females, never male, can go into diapuase (anhydrobiosis) for mad long which can rid them of pathogens
why have rotifers been asexual so long?
many benefits to being asexual but one problem is dealing with pathogens, rotifers solve this by going dormant for long periods of time
the resemblance of an adult individual to its juvenile form
development of lungs
probably originated from air bladder in fish (physoclistous), had to overcome challenges: need lots of surface area and limit water loss
Life needed ____ to go from water to land
Need: ability to breath and minimize water loss so you don’t dry out, structural support, movement: capture food and escape predators
Evolution of insects
Origin of hexapods, wings, wing folding, complete metamorphasis, co-evolved with plants
Insects so successful because:
- Wings
- Ability to fold wings behind back (pterygota)

Complete metamorphosis (homometabolous)
costs of being sexual
- Male production in sexual populations entails an ecological cost
- Cost of meiosis (decreased relatedness)
- "bet hedging" (forego high success to have predicatability)
Benefits of being sexual
Protostomes (stoma = mouth)
Early development: blastopore becomes mouth
Assymetrical cleavage
Cell fate determined by 8th cell
Early development: blastopore becomes anus
Radial/symmetrical cleavage
Cell fate indetermined by 8th cell
cavity between gut and bodywall
cavity open to outside
endoderm and ectoderm
characteristics of animalia/metazoa
- Multicellular
- Heterotrophic
- Collagen (usually) (25-35% of whole body protien)
- Unique muscle and nervous tissues
- Lifecycle with diploid phase dominant
double membrane bounded organelle usually involved in synthesis and storage of food. chloroplasts are one kind.
found in cell wall of bacteria only. also bacteria have no nucleus.
bet-hedging .
The behavioural response of a species population to a K-selecting environment in which occasional fluctuations in conditions affect the mortality rate of juveniles to a much greater extent than of adults. In such a situation adults release young into several different environments to maximize the chance that some will survive