2. How long does it take for an ice age to develop? What makes it end?
3. What other bees besides European honey bees (Apis mellifera) do a type of waggle dance? How does it work?
4. When and where did the first human (Homo sapiens) come to exist? How were they related to and distinguished from other primate relatives?
Specific plants, such as the orchid Ophrys sphegodes, are pollinated by male bees that are sexually attracted to the plant. An orchid takes advantage of a sexually excited bee by using visual cues along with pheromones to attract the bee, which will then help the plant pollinate. The bee takes note of the pheromones in each unique flower in the species, and will not visit the same flower twice. Instead, it is more likely to go to a different flower, but of the same species.
ReplyDeleteAyasse, M. (2000). Evolution of reproductive strategies in the sexually deceptive orchid Phyrys sphegodes: How does flower-specific variation of odor signals influence reproductive success? Evolution, 54(6), 1995-2006. doi: 10.1554/0014-3820(2000)054[1995:EORSIT]2.0.CO;2
--Michelle Corrado
2.
ReplyDeleteIt is universally accepted that the main ice-age rhythmic cycle is 100,000 years. It is based, along with other factors, on the response to the global carbon cycle. This causes changes in the concentration of carbon dioxide in the atmosphere. This was found by analyzing the oxygen content in deep-sea sediment. The ending of an ice age, or an increase in temperature, is correlated with an increase in salinity of the sea surface. Increased salinity is caused by combining horizontal flow of air and water with wind-induce evaporation to lead to an intensified circulation and an increase in temperature.
Shackleton, N.J. (2000). The 100,000-year ice-age cycle identified and found to lag temperature, carbon dioxide, and orbital eccentricity. Science, 289(5486), 1897-1902. doi: 10.1126/science.289.5486.1897.
Hendy, E.J. (2002). Abrupt decrease in tropical pacific sea surface salinity at end of Little Ice Age. Science, 295(5559), 1511-1514. doi: 10.1126/science.1067693.
--Michelle Corrado
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ReplyDelete4. When and where did the first human (Homo sapiens) come to exist? How were they related to and distinguished from other primate relatives?
ReplyDeleteThe earliest known fossils of Homo sapiens have been found in northern Africa, dating back between 150,000 and 200,000 years ago. Most genetic tracing was done through mitochondrial DNA. By now, most scientists agree on Africa as our place of origin and support an “Out-of-Africa” theory for the gradual dispersal of humans. Of the primates, chimpanzees are our closest relatives. We share a common ancestor with them from around 5-7 million years ago and 98% of our DNA. Humans and primates share many traits. We are very social creatures that tend to live in groups. Also, we are capable of aggression and killing of others of our own species. In some primate species, such as the Bonobo, continuous sexual activity is exhibited. Finally, the ability to distinguish beneficial plants from harmful ones and use them as medicinal tools are characteristics shared between us. Several characteristics distinguish humans and other former hominids from primates. First is an increase in overall brain size in humans. Second is the development of bipedalism and all of the morphological traits that support this type of movement, such as the placement of the skull upright on our vertebral column. Third is our advanced tool-making capabilities. It used to be thought that the increase in the relative size of our pre-frontal cortex accounted solely for much of our advanced intellectual capacities. However, new research points to other factors also contributing to this overall difference in intelligence, such as differences in cellular composition and connectivity. For instance, our Broca’s area (speech) and Wernicke’s area (language comprehension) are larger and more developed. No other primate has the capacity to have their own complex, spoken language such as we do. Finally, our slowed development, slowed sexual maturation, and increased lifespan, are characteristics solely of humans.
Carroll, S. B. (2003). Genetics and the making of Homo sapiens. Nature. 422, 849-857. Howard Hughes Medical Institute and Laboratory of Molecular Biology. Retrieved July 20, 2009 from www.nature.com/nature.
Gunz P., Bookstein, F. L., Mitteroecker, P., Stadlmayr, A., Seidler, H., and Weber, G. W. (2009). Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario. PNAS. doi: 10.1073/pnas.0808160106.
James Q. Jacobs. (2000). A Comparison of Some Similar Chimpanzee and Human Behaviors. Retrieved 20 July, 2009, from Paleoanthropology in the 1990's: Essays by James Q. Jacobs. Web site: http://www.jqjacobs.net/anthro/paleo/primates.html.
--Dallas Joiner
3. What other bees besides European honeybees (Apis mellifera) do a type of waggle dance? How does it work?
ReplyDeleteThe waggle dance is one of three dances of the honeybee. It is the most complex of the three and is used to locate food sources at great distances (>100m). In addition to European honeybees, Asiatic Honeybees, Apis cerana cerana, also do waggle dances. Though their dance differs in duration from the European honeybee, the Asiatic honeybee waggle dance still functions in the same way. The angle of the dance relative to gravity tells the direction of the food in relation to the sun. The duration of the “waggle” part of the dance gives the distance to the food source. Chemical signals given off by the dancing bees attract other bees to follow them and head out toward the food source. It was formerly though that waggle dances were a genetically inherited aspect of bees, given the minor distinctions in dances between different species. However, when testing a mixed population of Asiatic queen bees and both Asiatic and European worker bees, it was found that dances can be learned. In spite of the observed differences in dance durations between these two species, the European worker bees showed themselves to be just as successful at accurately locating food sources from the Asiatic bees’ waggle dances.
Su, S., Cai, F., Si, A., Zhang, S., Tautz, J., and Chen, S. (2008). East Learns from West: Asiatic Honeybees Can Understand Dance Language of European Honeybees. PLoS One, 3(6). doi: 10.1371/journal.pone.0002365. Retrived from PubMed Central database.
--Dallas Joiner
How long does it take for an ice age to develop? What makes it end?
ReplyDeleteAlthough many may refute the amount of time an ice age will develop is unpredictable, as mentioned earlier by Michelle C, the ice age rhythmic cycle is approximately 100,000 years. Delving deeper, to specify, there are two terms to be noted. The ice age is a description of glaciations, a period of time where the environment is at considerably low temperatures and life for many is unbearable. The earth fluctuates from glacial to interglacial. As the peak of the “ice age” begins to diminish, the Earth transitions to an interglacial period. The term interglacial is a description of a period unlike glacial period. The rate in which an ice age begins to develop is determined by many factors including the earlier mentioned in the other blog response. The position of the Earth in respect to the Sun causes changes in wind patterns and ocean currents. A recent article published in Science, geologist Stott refuted a claim that although carbon dioxide does indeed play a crucial role in the ice age phenomena, it is not the sole cause or end. Other possible reasons are being further examined.
Michelle Hwang
Visser, Katherine. 2003. Magnitude and timing of temperature change in the Indo-Pacific warm pool during deglaciation. 421:152-155.
Stott, Lowell. 2007. Southern Hemisphere and Deep-Sea Warming Led Deglacial Atmospheric CO2 Rise and Tropical Warming.
What other bees besides European honey bees (Apis mellifera) do a type of waggle dance? How does it work?
ReplyDeleteBy defining the term “waggle” dance, is a type of communication bees have with each other in regards to specifying the location of the food source. By performing the waggle dance, the bee performing the dance communicates with others watching where the food source is. The direction to the food source is determined accordingly by the direction of the food source to the sun. Similar to the European honey bees, Africanized bees also perform the waggle dance. Africanized bees are a hybrid of European honey bees and African bees. Not all bees will understand the movement of the waggling bee. The bee followers must be at least 30 degrees behind the dancing bee in order for understanding the dance. The position of the bee is very crucial.
Michelle Hwang
Judd, Timothy. 1994. The waggle dance of the honey bee. Journal of Insect Behavior. 8(3) 343-354. Doi: 10.1007/BF01989363
Schneider, S. 1995. Swarm movement patterns inferred from waggle dance activity of the neotropical African honey bee in Costa Rica. Apidologie. 26 (1995) 395-406
DOI: 10.1051/apido:19950505