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Chapter 3


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BIOL 1000
Julie Clark

Tanya Sivamanoharan Fri, Sept, 16/11 Biology- Chap# 3 Notes SELECTION, BIODIVERSITY, AND BIOSPHERE 3.1- Biodiversity -diversity of life on the biosphere is measured by # of species+ organisms -biodiversity the fact that life on earth exists from the bottom of ocean to high up in the atmosphere -biology is the study of life from the cell, to the multicellular organism, to the population, to the community, to the ecosystem, to the biosphere -according to taxonomy there are diff. kingdoms of organism -there is almost accurate info. about large species but there is no accurate information about some prokaryotes, and microorganisms -one way to group organism is by the way they obtain carbon b/c carbon is the backbone to all organisms -autotrophs synthesize organic carbon by using inorganic carbon (carbon dioxide) -heterotrophs obtain carbon from organic molecules (other organisms) -organisms can be divided according to the source of energy they use for biological activities -chemotrophs obtain energy by oxidizing inorganic or organic substances -phototrophs obtain energy from light -combining the carbon and energy sources of organisms, there are 4 ways to categorize them: 1. Chemoautotrophs 2. Chemoheterotrophs 3. Photoautotrophs 4. Photoheterotroph 3.2- Selection -selection occurs when a force affects the survival of an organism (Ex: spring frost killing garden plants) (an outbreak at the hospital is considered selection) -selection can occur when organisms in a large population are exposed to lethal matter and only the organisms with resistant material survive -If the resistant population can reproduce quickly, than there may be extensive growth of a population (Ex: say that bacteria can double their pop. in mins. and an antibiotic kill 99% of the bacteria, the remaining 1% will reproduce fast and in 20 mins. you can have 10 million new bacteria cells) -selection has influence towards evolution and biodiversity (3.2a and 3.2b are examples of selection) 3.2a- Case 1, Syphilis: Migration and Emergence of Disease -treponematoses  diseases caused by bacteria in genus treponema -treponema pallidum is the bacteria that causes syphilis -syphilis disease in the form of pox that starts small and painless but can turn to rash, fever and fatigue -it can cause disfigurement, neurological disorders, and cardiovascular problems if not treated -syphilis leaves marks on the skeleton which allowed to trace its origin -the first outbreak of syphilis was in 1495, and has killed many ppl. since -The history of T. pallidum has occurred in 3 steps: 1. T. pallidum was tho ught to be a nonvenereal infection that spread throughout humans in Middle East, Europe, and the New World. At that time the pathogen Tpallidum caused yaws, which was spread by skin-to-skin contact 2. T.pallidum then moved from the New World to Europe by exploreers like Christopher Columbus. The Europeans were clother and the natives in the New world were unclothed so there was minimal skin-to-skin contact but the yaws were in contact to europeans during sex. 3. T.pallidum in the genitcal area was transferred during sex and the result was syphilis 3.2b- Case 2, Evolution of Whales: A Change from Hoofed Mammal to Whale -first whale fossils were found in South Asia 50 million yrs. ago -paleontologists predict that the ancestors of whales lived like hippos and stayed in water to hide from predators and came to shore to eat vegetation -it was thought that hippos were related to whales but timing and location of origin demolish those predictions -in 2007 Hans Thewissen found evidence of ancestors closely related to whales -these species were apart of the genus Indohyus called Ecocene found in Kahmir India -ecocene lived similarly to hippos and shared a close ancestor with whales -indohyus had dense bones and high oxygen isotope levels, showing signs of aquatic life -they also had crushing basins in their molar teeth and had levels of carbon isotopes which support that they ate terrestrial plants -Eocene similar to whales, stayed in water to hide from predators and came out at night to eat vegetation -Thwissen’s proposal explained the evolution of an aquatic mammal from a terrestrial one, and a herbivore to a piscivore -genetic variation, survival of individuals that used water to avoid predators, and organisms switching their diets to fish were the main 3.2c- Case 3, Climbing Plants: Reaching for the Light --plants (trees) reach for the sun by growing tall -climbing plants are known as vines or lianas, which grow on trees, and they have equal or greater biomass and reproductive output -climbing plants grow quickly compared to trees and, therefore reaches the sun quicker -atleast 130 plant families include climbing species, and vines make up 40% of plants in a tropical forest -in 2004 Ernesto Gianoli compared 48 groups of plants in which he found evolutionary evidence between climber and nonclimber sister groups -he found that in 38 cases climbing taxa were more diverse than noncllimbers -he concluded that climbing was key in plants b/c it resulted in more species of plants -the diversity of climbing plants are classified by the structures they use for climbing such as tendrils, modified stems, or leaves, which coil around supporting structures (trees) -other climbers use modif. roots to attach to supports (trees) -in others the stem itself wraps around the support (trees) -Charles Darwin was one of the first to study climbing plants 3.3- Evolution evolution a gradual change in organisms, can be b/c of selection -evolution is a key to understanding diversity of life but some countries do not approve of evolution and do not teach it -this book teaches evolution b/c it is a key to biodiversity but not to say that humans came from apes -theory of evolution states that all organism came from common ancestor n/c we all have ATP as energy and DNA as genetic info., and a plasma layer made of lipid bilayers -evolution says that species change by natural selection -natural selection -indiv. organisms vary in heritable traits -all populations have ability to reproduce more than the environment can support so only some survive -some individuals in a population have special traits which is an advantage in survival and reproduction -the organisms with special traits will pass it on to offspring and soon the population will change b/c of that trait -dif. envir. support diff. traits so even though all organisms came from common ancestor they have changed b/c of selection pressure of environments 3.3a- Adaptive Radiation: Diversification of Lineages of Life -organism had to keep adapting to diff. situations that lead to diversification -photosynthesis was a change which let organisms convert solar energy to chem. energy, this helped the survival of some organisms -oxygenic photosynthesis lead to oxygen in the atmosphere as a by product which lead to aerobic respiration and the ozone layer, which blocked UV light from reaching organisms -an increase in atmospheric oxygen created a whole line of diversification -organisms may move adaptive zones and use the environment to their advantage (EX: plants moving to land) -there was once a diversity of soft bodied organisms in the Precambrian sea but not after the beginning of the Cambrian sea which saw an extinction in soft bodied organism and was a rise to many species with skeletons -the change from soft body to hard body is in the fossil record but not sure why 3.3b- Islands- Showcases of Evolution -adaptive radiation occurs when there is an evolutionary breakthrough allowing diversification of life -important factor to biodiversity -Hawaii was an island where many of the plants had undergone adaptive radiation -violets became shrubs -these adaptation occurred b/c the plants did not meet shrub or tree lifestyles -Hawaii is a place of evolution and adaptive radiation -adaptive radiation on islands show that adaptive radiation can happen in diff. parts of the world at the same time 3.3c- Land: Organisms Conquer a New Frontier -movement of organisms onto land proposed mny. challenges -these challenges included support, water conservation, reproduction and disposal of waste -there
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