QILIN_GUAN_-_Lab_23_-_Primate_Evolution_Cladistics_and_Bioinformatics

Lab #24 Primate Evolution, Cladistics, and Bioinformatics Date: 4/19/21 Purpose: 1. Observe and compare specific skeletal features of various primate species 2. Evaluate evolutionary trends and relatedness among species based on both morphological and biochemical factors 3. Construct a cladogram highlighting these traits Part A: Cladistics Based on Morphological Data ● You may find it helpful to watch this video before beginning this section or while you work. ● Visit this website to explore some primate skeletons. You will NOT need to examine all the species available, just the ones in the table. I have blacked out some traits to help you make efficient use of the information. Trait Tarsier Human Squirrel Monkey Gorilla Orangutan Slow Loris Chimpanzee Gibbon Baboon Grasping fingers yes yes yes yes yes yes yes yes yes Opposable thumbs no yes no yes yes yes yes yes yes Binocular vision yes yes yes yes yes yes yes yes yes Relatively small eyes no yes no yes yes no yes yes yes 2.1.2.3 dentition* no yes yes (2.1.3.3 ) yes yes no yes yes yes No tails tail No tail tail No tail No tail No tail No tail No tail tail Average size > 50 lbs no yes no yes yes no yes no yes Minimal sexual dimorphism yes yes yes yes Pelvis: short/wide or long/narrow long short long short short long short short long S-shaped spine no yes no no no no no no no No opposable big toe yes yes no no no no no no no *Dentition refers to how their teeth look. 2.1.2.3 refers to how many of each TYPE of teeth a species has in a single quadrant - in this case, 2.1.2.3 would indicate 2 incisors, 1 canine, 2 premolars, and 3 molars (this would be 4 incisors, 2 canines, 4 premolars and 6 molars on a single jaw). Some primates have 2.1.2.3, while others have 2.1.3.3. If you are having trouble, just count the total number of teeth for these ones.

Analysis: ● Answer each of these questions THOROUGHLY (you should end up with about a paragraph for each). Make sure that any claims you make have evidence, either rooted in your observations and/or found on the eskeletons website. 1. What traits set primates apart from other mammal species? Give a description of how those traits provide advantages in the primates’ environment. The traits that set primates apart from other mammal species are grasping fingers and binocular visions. Based on the table I’ve created, all nine of the primates have grasping fingers and binocular visions. This shows that mostly all primates have these two traits and when species have these two traits, you can easily see them as primates. Since most primates climb trees or live in forest environments, having grasping fingers allows them to grab on branches easily and grab other things like food. Binocular visions allow primates to see things at a much deeper perception, which allow them to focus on something clearly. 2. What information can be gained from the relative size and shape of the eye? What predictions about the primates’ lifestyles can we make, and how might the evidence support that claim? Primates with small size bodies and weight can tell us that they climb and live on trees. Smaller primates climb trees because they are small and trees are able to handle their weight. Primates that live on trees also swing around and their low weight allow them to do it easily. Larger primates live on land and don’t swing around trees. Because they’re bigger, their body weights are heavier, which make climbing and living on trees harder. Primates with big eyes allow more light to enter the retinas and result in seeing better in the dark and have a higher resolution. Tarsier is a primate that has big eyes; it can see better in the dark which tells us that a tarsier hunts at night. 3. What trends do you notice in the teeth and jaws of these primates? Describe specifically what the dentition tells you about the lifestyle of these animals and how their bodies worked. Compare this with other groups of mammals if you’d like. Most of the primates –except tarsier and slow loris– have 2.1.2.3 dentitions which include incisors, canine, premolars, and molars. Having these different teeth indicate that these primates have several sources for food. They are able to eat hard food using their premolars and molars. The Canine helps tear food apart while the incisor helps with cutting the food or biting. With different types of teeth these primates have the choice to eat fruits, nuts, plants, or meat. Their bodies will take in proteins from all sorts of food sources. 4. What predictions can be made about the primates’ lifestyle based on their size, tails, and limbs? How does each piece of evidence support that claim? Based on the size, bigger and heavier primates stay on land more than climbing trees. For example, gorillas are relatively big so stay on land more but they also climb trees and sometimes sleep there. Tails in primates are used for balancing and sometimes for grasping branches. The individuals in the table with tails mostly likely hangout on trees more often than on land. For example, tarsiers are small and they jump from one tree to another easily because of their size and also the tails help them balance the landing. Gibbons’ lifestyle are mostly swinging around which is why their limbs for their arms are longer than other primates. 5. What is sexual dimorphism? Why do you think some species show extensive sexual dimorphism and others do not? Sexual dimorphism is differences in size, appearance, and sexual organs between the sexes of an animal. Some species show extensive sexual dimorphism because (mostly) the females chose the males with the better appearance. Their offspring would have a high chance of inheriting those popping appearances. As this continues, the less better looking traits will decrease as no females would want to mate with them. The

Orangutan 2 12 3 2 9 9 6 0 2 7 Gibbon 3 14 4 3 9 8 6 2 0 5 Baboon 8 16 7 8 12 7 3 7 5 0 Cladogram: ● Create a new cladogram based on this new information. Conclusion : Use these prompts to help guide your writing. ● How do the traits we examined help differentiate between species? What other traits could we have observed? ● How similar or different are the cladograms you built? In what ways can morphological data be valuable? In what ways is it limited? ● Explain how reproductive isolation creates biodiversity and can result in speciation. ● What mechanisms lead to reproductive isolation? ● How do the primate species you observed demonstrate these processes?