GEOL 333 Lecture 11: Arthropods (2_16_21)
22 Feb 2021
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What can increase the rate of evolution: a small population size. What is a species according to ecological species concept: a lineage which occupies a niche different from that of any other species . What is a general consequence of increased body size: smaller population size. Approximately how old is the earth: 4. 5 billion years. Made of cuticle - non-cellular material secreted by the epidermis. Aquatic arthropods can extract calcium carbonate from the water and easily add it to their exoskeleton. Once secreted and hardened, the cuticle does not grow. To get bigger, arthropods must molt - shed their exoskeleton. During a molt, an arthropod reabsorbs the inner layers of the exoskeleton and swells its body. Until it hardens, the arthropod is vulnerable and largely immobile. Most use muscles attached to the inside of the skeleton. Multiple legs are a consequence of the segmented body plan, Exoskeleton covers the body, removing the sense of touch.
