Universe 145 bya rate of expansion of the universe Earth 45 bya oldest

Universe 145 bya rate of expansion of the universe

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Universe- 14.5 bya, rate of expansion of the universe Earth- 4.5 bya, oldest radioactively dated rocks Life on Earth- 3.5 bya, oldest fossils 4. What are two costs of group living? What is meant by the term “net benefit”? i. Increased competition for resources, ii. Increased exposure to diseases and parasites Net benefit means the advantages outweigh the costs, so overall there is a selective advantage. 5. List and briefly describe two fates of a duplicated gene (paralog). i. Neofunctionalization – takes on a function different from the original one ii. Subfunctionalization – changes to only to one part of the function of the original gene iii. Pseudogene – loses all functionality as a gene 6. What are homonins and how long ago did they diverge from the other extant homonids? All of the non-ape hominids, including humans and their close relatives. About 5.5 mya
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Not-As-Short Answer (8 points) 1. a. What is allopatric speciation and what type of barrier to gene flow is most apparent under this mode of speciation? When speciation occurs after a population has been split into two geographically isolated groups, some physical barrier (space, ocean, mountain, etc.) prevents gene flow b. List one example of a barrier to gene flow that can cause differentiation of populations living in a sympatric distribution. Ecological – different cichlid fish live in different parts of a lake, specializing in different niches Temporal – different cicada species emerge to mate on different cycles Behavioral – two birds prefer a different type of mating call (Specific examples may vary from those listed above) c. What is meant by the term hybrid zone and under what mode of speciation do we commonly see the formation of hybrid zones. Hybrid zone is an area where two distinct populations can interbreed a little bit, facilitating a small amount of gene flow. Parapatric speciation Bonus: What distinguishes the peripheral type of allopatric speciation from the other type? In the peripheral type a very small group breaks off from the main group. This causes rapid change of the small group due to genetic drift, while the main group remains relatively unchanged.
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