BSC 1105 Vertebrate Biology Exam #3 Study GuideI. Thoughts on Natural SelectionA) Darwin’s Four Postulatesi. Darwin wrote On the Origin of Species by Means of Natural Selection, in which he explained his four postulates about the origin of species.ii. His four postulates include:1) Individuals within species vary2) Some of the variations found in the population are passed on to offspring3) In every generation more offspring are produced than can survive4) The survival and reproductive success of individuals is not randomiii. Darwin often talked about what he liked to call “fitness”, which pertains to the degree an individual contributes genes to future generations.B) Sexual Selectioni. Darwin suggested that sexual selection came in two forms:1) Direct competition between males for females2) The female does the choosing among many male competitors *Understand the Vertebrate diversity chart (How to read it and answer any corresponding questions)II. The Phylum Chordata: Subphylum Vertebratai. All vertebrates share the following traits:1) A notochord2) Pharyngeal slits3) A dorsal hollow nerve cord4) A postnatal tailii. It is believed that the the ancestor to the vertebrates may have been the Chordate, or the Pikaia gracilens.iii. Ostracoderms were the first known vertebrates, they were jawless and were classified as Agnathans. III. The Origin of the Vertebrates: Jawless FishA) Superclass Agnatha: Jawless Fishi. There are five classes with only Myxini and Cephalaspidomorphi being the only existing ones. Myxini include living hagfishes, while Cephalaspidomorphi include the living lampreys. They both are jawless and the notochord of cartilage persists throughout life in both classes.ii. This Superclass Agnatha has the ostracoderms(extinct) and living fish (lampreys and hagfish). This group is essential because the ostracoderms are believed to be the ancestors of the jawed vertebrates.IV. Jawed FishA) The three major groups of living jawed fish include: 1) Chondrichthyes (rays and sharks)2) Sarcopterygii (lungfish)3) Actinopterygii (ray-finned fish)B) Class Chondrichthyesi. These fish do not have any bone in their bodies, as they are composed entirely of cartilage except for their teeth and scales.ii. They first appeared in the Silurian period of the fossil record.C) Class Sarcopterygii and Class Actinopterygiii. These classes are known as the bony fish and referred to as Osteichthyes. ii. Sarcopterygii are believed to be the direct ancestors of tetrapods(land vertebrates). iii. Specifically, a member of the Superorder Crossopterygii is believed to be the direct ancestor of the amphibians (the first tetrapods). iv. Actinopterygii are ray-finned fish that have two subclasses. Chondrostei are considered primitive ray-finned fish while Neopoterygii are considered advanced, modern ray-finned fish. V. Tetrapods (Amphibians and Reptiles)A) Class Amphibiai. The oldest known animals in this class were the swamp-dwelling labyrinthodonts (had a labyrinthine folding of teeth on cross section). ii. The amphibians are descendants of a Crossopterygian fish ancestor. i. Amphibians have webbed feet, usually four limbs and bony skeletons. In addition, they have glandular skin that helps when breathing. Because of many of these traits, this group is tied to water. B) Class Reptilia (Carboniferous)i. They have three major lines of descent: one to turtles, another to mammals andthe last to snakes, lizards, crocodiles, alligators, and birds.* Know the Sublclasses: Subclass Anapsida (turtles), Subclass Lepidosauria (lizards and snakes), Archosauria (ancestor to crocodiles, alligators, and birds) VI. Birds and MammalsA) Class Aves (Jurassic)i. Birds outnumber all vertebrates besides fish . They are derived from a bipedal Archosaurian reptile, and have similar bone and muscle structure to reptiles. Hence, earning them the name of “glorified reptiles”. *Know that Aves are descendants of dinosaurs.ii. Birds are endotherms (making them warm-blooded animals) and allows them tomaintain a constant body temperature regardless of temperature change. Animals like that of fish, amphibians and reptiles are ectotherms (cold-blooded animals). iii. Archaeopteryx are the earliest vertebrates classified as birds and the most well-known. VII. Reproductive BehaviorsA) There are various modes of reproduction among vertebrates.i. Oviparous development are when animals like fish, all amphibians, many reptiles, birds, and two mammal species lay eggs (With eggs being fertilized externally or internally). On the other hand, viviparous development is giving birth to non-shelled, live offspring like dogs and horses. *Know that the Class Mammalia is viviparous. B) Vertebrates use different mating systemsi. Monogamy is the association between one male and one female, while Polygamy refers to the association between an individual that has more than one mate at the same time. ii. Polygyny refers to the association between one male and two or more females, while polyandry is the association between one female and two or more males. iii. About 90% of all bird species are monogamous, while monogamy is not found greatly in mammals (3% of mammals are monogamous).iv. Most mammals are polygynous or promiscuous (both males and females have Multiple partners during a breeding season) *Know that fraternal polyandry is when several brothers marry a single wife.VIII. Social BehaviorsA) Selected Social Behaviorsi. In a study done on a group of meerkats, scientists from Cambridge University followed their day-to-day activities. This program was named Meerkat Manor and was conducted for ten years. ii. The leader of the meerkats, named Flower, was a female (Thus the group was matriarchal). On the other hand, if it were led by a male it was be considered a patriarchal group. iii. The members of the meerkat group are:1) Flower : leader and dominant female of the Whiskers group2) Zaphod : the dominant male and Flower’s mate3) Shakespeare: the older son of the Flower and Zaphod4) Mozart : Shakespeare’s sister5) Tosca: Sibling of Shakespeare and Mozart, she becomes pregnant by an unknown mal and leads to problems between her and Flower6) Youssarian: Another sibling and a real problem to the group7) Young pups (Mitch and Axel): meerkat babies 10 months or youngerIX. Animal MovementsA) Migration Movementsi. Animals perform these movements in order to secure food, avoid unfavorable
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