The Evolution of Jawed Fishes Ancient vertebrates evolved about 520 million years ago. They were small and jawless and had to use their lips to grab prey. These jawless vertebrates dominated the seas‚ but now only a few species of them have survived‚ namely the lampreys and hagfishes. Originally‚ most ancient fishes consisted of bottom-feeding armored fishes that lacked jaws called the ostracoderms‚ who swam the Silurian and Devonian seas. They had protective armor that was made of plates of
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Human Impacts on island ecosystems. (Australia) There are few paleovegetation records in Australia before 18‚000 years ago. To find out the history of the Australian fauna scientists used stable carbon isotopes from the emu eggshell (a flightless bird native to Australia). The samples were largely taken from Lake Eyre. The carbon composition of the eggshell tells us the composition of the bird’s diet (over 3-5 days). The emus are mixed feeders herbivores‚ eating leaves‚ shoots‚ fruits‚ flowers
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by the removal of sharks remain misleading‚ due to the significant declines in large coastal sharks in the northwest Atlantic Ocean‚ which caused dramatic increases in abundances of smaller elasmobranchs (referred to as “Macropredators”) over the predation release. The large coastal sharks decline allegedly led to an order of large scale increase in the population of Cownose rays. Thereby the ever-increasing feeding of the cownose ray has led to the concerns for the shellfish populations along the
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INTRODUCTION: Competition occurs between any organisms living in a mutual habitat. Whether it is for food‚ water‚ shelter‚ or a mate‚ competition can be harmful or helpful to each organism. There are two basic types of competition; intraspecific and interspecific. These terms refer to competition within a specific species and the competition between different species‚ respectively. In this lab‚ we conducted 3 basic experiments. Our goal was to observe the effects of the competition in each instance
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The Colorful Guppy Lab Report Problem: What is the relationship between the brightness of the guppy and their predators and mates? Hypothesis: If predators attack the guppy populations‚ then the drab guppy population will increase due to high predation. Materials: 1. Guppies 2. Computer Data Table: | % of Brightest Guppies | % of Bright Guppies | % of Drab Guppies | % of Drabbest Guppies | Trial 1 | 62 | 9 | 22 | 7 | Trial 2 | 16 | 9 | 21 | 52 | Trial 3 | 10 | 10 | 25 | 50
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against individuals 2. Cybercrimes against groups 3. Cybercrimes against property 4. Cybercrimes against corporations 5. Cybercrimes against governments 1. Cybercrimes against individuals Identity Theft Sexual Predation Confidence tricks and con artists Financial Predation It is fascinating to observe the number of cybercrimes against individuals that are reported on a daily basis Just within the weeks before my departure for this trip‚ the following items were in the LA Times and Daily
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Scientific & Common Name: The Canada Goose (Branta canadensis) Habitat & Geographic Range: The Canada goose population is spread throughout Canada and United States‚ and can live in different conditions of many biomes such as Tundra‚ Grasslands‚ Temperate regions‚ and Boreal Forest (Mowbray et al.‚ 2002). Their ability to inhabit variety of biomes allows incredibly wide range of habitats available for the Canada goose. Habitats range from cold arctic to temperate forests. They can be found near
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whole species and have caused irreparable damage to the surrounding ecosystem. For example‚ alien insects‚ organisms‚ plants cause damage to crops and forests. Some invasive fishes contributed to the disappearance of a lot of fish species through predation and competition for food. Migratory crab‚ during his mass migration contributes to the temporary disappearance of endemic invertebrates.
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important aspects of an organism’s life. Sleep allows living things to rest and store energy that will be needed once they awake. If you think about it‚ sleep does have some serious evolutionary disadvantages. When asleep‚ you are vulnerable to predation and sudden changes in the environment. Studies have shown that birds and other mammals can sleep with one eye open and one half of their brain awake‚ a phenomenon called unihemispheric sleep. The Mallard duck is one type of animal that
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RESULTS Aphid survival experiment Aphid survival rate varied with both of different combinations of predators-aphids and various times in presence or absence of ants (Table 2). GLM results showed that the interaction of ‘time × different combinations of predators and aphids × ant’ (F = 0.211; df = 10‚ 317; P = 0.995)‚ ‘ant × time’ (F = 0.490; df = 2‚ 317; P = 0.613) and ‘different combinations of predators and aphids × time’ (F = 1.639; df = 10‚ 317; P = 0.095) on the survival rate were not significant
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