S: Seasons of Change
FC: Evolutionary Paths
1: Grant's Zebra
2: Adaptations The zebra's stripes serve a variety of purposes. They serve as camouflage by making it hard to distinguish individuals, help with identification by the herd, and create cooling airflow when heat rises over the dark stripes and causes airflow. They have flat teeth perfect for chewing on tough savannah grass. They have strong legs with single hooves that allow them to run quickly over long distances.
3: Fossil Record | eohippus | megahippus | mesohippus | miohippus | merychippus | pliohippus | equus | __ | ___ | __ | __ | __ | ___
4: Embryology | The zebra at the top left is a Grant's zebra. The Grant's zebra has wider stripes because they develop two week earlier than in the Grevy's zebra. This means that there is less original surface area and therefore fewer original stripes. Because there are fewer stripes, each stripe has more room to grow as the zebra develops compared to the surface area per stripe on a Grevy's zebra as it develops.
5: DNA Evidence | The relationship between horses and plains zebras(which include the Grant's zebra) are supported by the similarity of the DNA. In one study where two sequences were tested for similarity throughout the equids, plains zebras were found to diverge only 2.1% on one sequence and 3.6% on the other from the modern horse.
6: Ostrich (struthio camelus)
7: Adaptations | Ostriches have very strong legs which allow them to run at high speeds in order to evade predators such as lions. They can run at 30 mph for 30 minutes! Ostriches also have the largest eyes of any terrestrial vertebrate. This helps them to watch out for predators so | that they won't have to run. Ostriches have also evolved so that they can process grasses unlike other birds in their family. This makes it easier to find food on the savannah, which is almost entirely grassy.
8: Embryology | This picture shows how the ostrich foot develops into three main toes while the 1st and 5th toes become vestigial structures. This was used to prove that ostriches are not descended from theropods, who retain the first, second, and third toes only.
9: DNA Evidence | Recent study of the DNA of moas, an extinct flightless bird like the ostrich, suggests that it is more closely related to a flying bird than other flightless birds or ratites like the ostrich. This means that ratites probably evolved separately through convergent evolution.
10: Fossil Record | Similarities between bone structure of today's ostrich and palaeotis weigelti from the Middle Eocene period. | This is a feather from an early species of neornithes. This subclass of birds was the one to survive the meteor impact that ended the dinosaurs, making it the first group of modern birds.
11: Live Oak (quercus virginiana)
12: Adaptations to the Environment | Live oak trees have evergreen leaves, which allow them to keep producing food through the process of photosynthesis during the winter. They can also produce shoots, which are stem-like projections of the roots that can produce a new tree. This allows them to reproduce quickly when the original plant is injured. The leaves have a waxy coating to protect against water loss from the salty conditions that these trees typically grow in, such as maritime regions.
13: Embryology | All oak trees produce acorns from the flowers of the plant after pollination. The acorn germinates almost immediately after falling from the tree if it is kept moist, compared to one to 13 months for other oak species. Live oaks, like other members of the Magnoliopsida class, produce two cotyledons within the acorn.
14: Fossil Record | This fossilized oak leaf is from the Miocene era, 16 million years ago. It looks very similar to a live oak leaf.
15: DNA Evidence | Researchers are currently studying oak genomes to see if some populations are resistant to the bacteria causing sudden oak death. So far, however, they have only identified differences in populations and not the effects that these mutations could have.
16: Harbor Seal | (phoca vitulina)
17: Adaptations Harbor seals have gradually inherited a thick layer of blubber which keeps them warn while they're in the water. A double layer of fur also keeps them warm while diving and provides a waterproof barrier. Seals also have whiskers which helps them sense where prey such as fish are.
18: DNA Evidence | The total nucleotide difference between grey seals and harbor seals was determined to be 2-6%. By comparing their DNA to that of Hawaiian monk seals and Weddell seals, researchers determined that the two groups split eight million years ago. They also estimated that grey seals and harbor seals diverged 2-2.5 million years ago.
19: Embryological Development Embryos go through a period of delayed implantation. This period is usually two and a half months long. The purpose of the delayed implantation is to insure that the pups are always born in early summer. This is a common trait in pinnipeds.
20: Fossil Record | This is pujilla darwini, the earliest known ancestor of the seal. It walked on four legs but had webbed feet. | Enaliarctos was next in line toward the evolution of the seal. It had similar ear structure to modern seals, but had to eat on land.
21: Works Cited | Highfield, R. (1998). The Physics of Christmas: From the Aerodynamics of Reindeer to the Thermodynamics of Turkey. Retrieved from: http://books.google.com Haumod, H. & Houde, P. (!987, June 20). Palaeotis Weigelti Restudied: A Small Middle Eocene Ostrich. Retrieved from: http://biology-web.nmsu.edu/houde/Palaeotis.pdf. (2011, July 26). Retrieved from: http://www.britannica.com/blogs/2011/07/evolutionequine/ (2009, Apr. 23). Retrieved from: http://sciencenotes.wordpress.com/2009/04/23/transitional-seal-fossil/ Gullberg A., Ledje C., Johnsson E., & Arnason U. (1993). The nucleotide sequence of the mitochondrial DNA molecule of the grey seal, Halichoerus grypus, and a comparison with mitochondrial sequences of other true seals. Retrieved from: http://www.uniprot.org/citations/8308902
22: Feduccia, A. & Nowicki, J. (2002, Aug. 14). The hand of birds revealed by early ostrich embryos. Retrieved from: http://biology-web.nmsu.edu/houde/Feduccia_2002.pdf. Alberdic, M., Austin, J., Bonjeane, D., Cherryr, M., Cooperb, A.,Orlandoa, L., Metcalfb, J., Telles-Antunesd, M., Ottef, M., Marting, F., Eisenmannh, V., Mashkouri, M., Morelloj, F., Pradok, J., Salas-Gismondil, R., Shockeym,B., , Ovodovq, N., Hopwood, B., Maleb, D., Hnnia, C., Vasil'evp, S., and Wrinno, P. Revising the recent evolutionary history of equids using ancient DNA. Retrieved from: http://www.pnas.org/content/suppl/2009/12/09/0903672106.DCSupplemental/ST3_PDF.pdf (1998). Adaptations. Retrieved from: http://www.abc.net.au/oceans/seals/adaptations.htm. (2011). Harbor Seal. Retrieved from: http://www.deepseawaters.com/harbor-seal.htm Grant's Zebra. Retrieved from: http://seaworld.org/animal-info/animal-bytes/animalia/eumetazoa/coelomates/deuterostomes/chordata/craniata/mammalia/perissodactyla/grants-zebra.htm (2006, Oct. 28). The Self-Nade Tapestry. Retrieved from: http://www.kk.org/cooltools/archives/001099.php Zebra. Retrieved from: http://www.zookeeperjournal.com/zebra.php Miohippus. Retrieved from: http://www.flmnh.ufl.edu/fhc/mioh.htm
23: (2001, Jan. 17). Harbor Seal. Retrieved from: http://www.alaskasealife.org/master/animal_fact/factsheet_harborseal.pdf (2011, Sept. 23). Amber Fossils, Green Light to Feather Evolution. Retrieved from: http://jkendrickensis.wordpress.com/2011/09/23/amber-fossils-give-green-light-to-feather-evolution/ Houde, P. (1986, Dec. 11). Ostrich ancestors found in the Northern Hemisphere suggest new hypothesis of ratite origins. Retrieved from: http://www.nature.com/nature/journal/v324/n6097/abs/324563a0.html (2010, Jan. 26). Dinosaur Extinction Grounded Ancient Birds, New Research Finds. Retrieved from: http://www.sciencedaily.com/releases/2010/01/100126105429.htm Ostrich DIet. Retrieved from: http://www.ostrich.com/library/diet.html Klappenbach, L. Ostrich - Struthio camelus. Retrieved from: http://animals.about.com/od/birds/p/ostrich.htm (2007, Feb. 1). Taxonomy. Retrieved from: http://www.damisela.com/zoo/ave/ratities/avestruz/taxae.htm