BSC 1105 Vertebrate Biology Exam 3 Study Guide I Thoughts on Natural Selection A Darwin s Four Postulates Individuals within species vary Darwin wrote On the Origin of Species by Means of Natural Selection in which he explained his four postulates about the origin of species His four postulates include 1 2 Some of the variations found in the population are passed on to offspring In every generation more offspring are produced than can survive 3 4 The survival and reproductive success of individuals is not random Darwin often talked about what he liked to call fitness which pertains to the degree an individual contributes genes to future generations B Sexual Selection Darwin suggested that sexual selection came in two forms 1 Direct competition between males for females 2 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 Vertebrata III The Origin of the Vertebrates Jawless Fish A Superclass Agnatha Jawless Fish All vertebrates share the following traits 1 A notochord 2 Pharyngeal slits 3 A dorsal hollow nerve cord 4 A postnatal tail It is believed that the the ancestor to the vertebrates may have been the Chordate or the Pikaia gracilens Ostracoderms classified as Agnathans were the first known vertebrates they were jawless and were 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 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 i ii iii i i ii iii i ii IV Jawed Fish A The three major groups of living jawed fish include 1 Chondrichthyes 2 Sarcopterygii 3 Actinopterygii lungfish ray finned fish rays and sharks i ii i ii iii iv i ii i i ii iii B Class Chondrichthyes These fish do not have any bone in their bodies as they are composed entirely of cartilage except for their teeth and scales They first appeared in the Silurian period of the fossil record C Class Sarcopterygii and Class Actinopterygii are believed to be the direct ancestors of tetrapods land These classes are known as the bony fish and referred to as Osteichthyes Sarcopterygii vertebrates Specifically a member of the Superorder Crossopterygii is believed to be the direct ancestor of the amphibians the first tetrapods 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 Amphibia The oldest known animals in this class were the swamp dwelling labyrinthodonts had a labyrinthine folding of teeth on cross section The amphibians are descendants of a Crossopterygian fish ancestor 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 They have three major lines of descent one to turtles another to mammals and the 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 Mammals A Class Aves Jurassic 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 i Know that Aves are descendants of dinosaurs Birds are endotherms making them warm blooded animals and allows them to maintain a constant body temperature regardless of temperature change Animals like that of fish amphibians and reptiles are ectotherms cold blooded animals Archaeopteryx known are the earliest vertebrates classified as birds and the most well VII Reproductive Behaviors A There are various modes of reproduction among vertebrates i i ii iii iv i ii iii development are when animals like fish all amphibians many Oviparous 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 systems 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 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 About 90 of all bird species are monogamous while monogamy is not found greatly in mammals 3 of mammals are monogamous 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 Behaviors A Selected Social Behaviors 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 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 The members of the meerkat group are leader and dominant female of the Whiskers group the dominant male and Flower s mate 1 Flower 2 Zaphod 3 Shakespeare 4 Mozart 5 Tosca unknown mal and leads to problems between her and Flower Shakespeare s sister Sibling of Shakespeare and Mozart she becomes pregnant by an the older son of the Flower and Zaphod 6 Youssarian Another sibling and a real problem to the group 7 Young pups Mitch and Axel meerkat babies 10 months or younger IX Animal Movements A Migration Movements i Animals perform these movements in order to secure food avoid unfavorable weather or raise their offspring ii For instance in fish migrations certain fish that perform a once in a lifetime migration are known as anadromous fish Know that certain fish i e Salmon need their sense of smell in order to migrate back to where
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