Introductory Biology II Concept Map - Aresha Bagheri
Biogeochemical Cycles
The Phosphorous Cycle
Organisms require it for nucleic acids, phospholipids, ATP and mineral components.
Most important inorganic form is phosphate, which plants use to create organic compounds.
reservoirs include...
sedimentary rocks
soil
oceans
organisms
phosphorous cycle
geological uplift
weathering of rocks
runoff
plant uptake
decomposition
leaching into aquatic environments
The Carbon Cycle
Carbon forms the framework of the organic molecules essential to all organisms.
Carbon is available in the form of CO2 to plants, which convert it to organic forms that are used by other organisms.
Major reservoirs of carbon include...
fossil fuels
soils
sediments of aquatic environments
the oceans
plant and animal biomass
the atmosphere
sedimentary rocks (the largest reservoir)
the carbon cycle
CO2 in atmosphere
Photosynthesis
cellular respiration
decomposition
consumers
phytoplankton
burning of fossil fuels
The Water Cycle
Water is essential to all organisms, and its avaliability influences the rates of ecosystem processes.
Liquid water is the primary physical phase of water.
The oceans contain 97% of water in the biosphere.
2% Of water is contained in polar ice caps.
1% of water is contained in lakes, rivers, and groundwater (negligible amount in atmosphere).
Water cycle
Evaporation by solar energy
Condensation of water vapor into clouds
Precipitation
Percolation through soil
Runoff and groundwater
Transpiration
The Nitrogen Cycle
Plants use two inorganic forms of nitrogen - ammonium and nitrate - and amino acids. Bacteria use these forms too as well as nitrite, animals can only use organic forms of nitrogen.
Reservoirs of nitrogen include...
the atmosphere (80%)
the soil
sediment
surface water and groundwater
biomass
the nitrogen cycle
N2 in atmosphere
NO3- in the water
aquatic cycling
Industrial fixation
fertilizers
runoff
denitrification
reactive N gasses
terrestrial cycling
Human Evolution
Hominids (Australopithicus and Homo) and apes diverged from a common ancestor 5 million years ago.
Human DNA is 98.8% similar to the DNA of chipanzees
The oldest Hominid was Ardipithecus ramidus
Ardipithecus was bipedal
Australopithecus anamensis
A. afarensis
4 million years ago
Lucy was an A. afarensis
discovered in Hadar, Ethiopia
A. africanus
3 million years ago
A. boisei
2.5 million years ago
A. robustus
2 million years ago
Taung child
discovered in South Africa
Homo rudolfensis
Homo genus evolved 2 million years ago
H. habilus
Lived 2 million years ago to 1.8 million y.a.
H. erectus
H. sapien
evolved 300,000 years ago
H. sapiens (Neanderthals)
died out 22,000 years ago
humans have 3% neanderthal DNA
H. sapien sapien (modern human)
evolved 50-35,000 years ago
1 million years ago
Turkana boy
was a toolmaker
The oldest fossil remains of human ancestors were found in Africa.
then spread to the Middle East
to Europe
to Asia
to North America via land bridge
to South America
to Australia
60,000 years ago
Domestication first occured in the Middle East an South Europe 11,000 years ago
trends in human evolution
brain size in Hominid lineage increased dramatically from 500 to 1350 cubic centimeters
longer lifes span and and longer dependency
development of language paralells the evolutionary process
evolution - changes in allele frequencies within a population
Energy Flow in Ecosystems
Energy is transferred from one trophic level to the next
Only 1/3 of energy is transferred from one trophic level to the next.
The rest of the energy is lost as heat.
the sun is the primary source of energy
producers
herbivores
carnivores
top carnivores
decomposers and detritivores
heat energy lost
heat energy lost
heat energy lost
Only .02% of the sun's energy is captured by plants
heat energy lost
net primary productivity
plant growth per unit area per unit time
gross primary productivity minus plant respiration
gross primary productivity is the total photosynthesis per unit area per time
heat energy lost
energy flow is non-cyclic
handling time - the time it takes from capture of food item by a foraging organism to digestion
An ecosystem is a group of organisms that are connected by energy and mineral flow.
Population Genetics
Genetic Variation in a Population
allele frequency
the proportion of a certain allele within a population
allele frequency=gene frequency=gametic frequency
gene pool
the set of all alleles at all loci in a population
Hardy-Weinberg Equilibrium
Allele and genotypic frequencies remain the same from generation to generation in a population in which there is...
no mutation
mutation - random change in the genetic code
the ultimate source of genetic variation in a population
mutation rates for many genes can vary from one out of ten to one hundred thousand
majority of mutations are detrimental
no genetic drift
genetic drift - random changes in allele frequencies from generation to generation
genetic drift results from sampling error in a population with limited size
founder effect - random changes in allele frequencies in a population during colonization
founder effect occurs within the same generation
bottleneck effect - random changes in allele frequencies within a population due to dramatic reduction of population size
reduction in size is either caused by some catastrophic events, or only the frequencies of those loci are considered that are not under selection
no migration
migration (gene flow) - the movement of genes between populations
migration rate - the proportion of immigrants in a population after migration
migration tends to eliminate existing genetic differences between populations
allele frequencies change in the direction of the doror/source population due to migration
p(M)=p(I)M+p(R)(1-M)
random mating
Inbreeding - mating between relatives - not random mating
leads to inbreeding depression - decrease of vigor or reproductive success due to inbreeding
selfing - most severe form of inbreeding
heterozygosity is halved between generations
positive assortive mating
increases homozygosity only at the locus for which the choice occurs
asexual reproduction
offspring are genetically identical to the parent
no selection
selection - differential reproduction among different phenotypes within a population
response to selection depends on the selection differential and the heritability of the trait in question
If Hardy Weinberg conditions are not met, then the population is evolving.
p+q=1, p²+2pq+q²=1
Global Warming
The increasse of the global average temperature on Earth
1 degree Celcius hotter on average
by the end of the century about 4 degrees Celcius hotter
The greenhouse effect - the trapping of heat in the atmosphere by certain greenhouse gasses.
CO2
CH4
produced in rice paddies, wet agriculture, intestinal system of cows, floors of oceans
nitrous oxides
produced naturally and man made
combine with sulfur dioxide to produce acid rain
CFC's
produced from cleaners, aerosols, refridgeration and cooling
Water vapor
caused by...
greenhouse gasses
such as CO2
human activity
depletion of the ozone layer
CFC's deplete ozone
future effects...
change in precipitation
rising sea levels
melting ice caps
warming oceans
more intense hurricanes
biological impacts
altitudinal/poleward shifts in species ranges
earlier spring events
coral bleaching
species extinction
Selection
natural selection
individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits
ex. antibiotics
artificial selection
the selective breeding of domesticated plants and animals to encourage the occurance of desirable traits
ex. corn crops
response to selection
heritability
proprotion of phenotypic variation that has a genetic basis
rated from 0 to 1, 0 is environmentally based, 1 is genetically based
selection differential
measures intensity or strength of selection
stabilizing selection
intermediates have advantage
directional selection
extremes are favored
ex. peppered moths
sexual selection
females chosing males based on their phenotype
ex.peacocks
2 components
males compete
females choose