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The Rate of Evolution and Extinction: Understanding Adaptation and Survival

This overview explores the dynamics of evolution and extinction, focusing on factors that influence the rate at which species evolve and the causes of extinction. Key elements include environmental changes, reproductive rates, and the importance of genetic variation. Rapid environmental shifts can lead to faster evolutionary changes, while species that fail to adapt may face extinction. Additionally, the misuse of antibiotics has created super strains of bacteria, demonstrating the practical implications of rapid evolution. Understanding these factors is crucial for conservation and managing biodiversity.

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The Rate of Evolution and Extinction: Understanding Adaptation and Survival

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  1. The Rate of Evolution and Extinction What affects how fast orgs evolve? What leads to extinction?

  2. Change is Everything! • Change in environment = Change in species! • Failure to adapt to changes = possible extinction 

  3. Rate of EvolutionWhat affects how fast a species evolves? • Rate of environmental change • Rate of reproduction

  4. Rate of Environmental Change • Rapid environmental change = rapid change in species • Rapid change • Ex. Modern horse: many changes over past million years • Slow change • Ex. Horseshoe crab: nearly identical to ancestors from 300 mya

  5. Rate of Reproduction • The # of offspring produced can tell us how quickly a species can evolve • Few offspring = longer life = slow evolution • Ex. Humans, elephants • Many offspring = shorter life = quicker evolution • Ex. Bacteria, single celled orgs, fish

  6. Antibiotic Resistance

  7. Let’s look at bacteria • Reproduce very quickly • Millions exposed to antibiotic • Very good chance a few will have resistantgene due to random mutation • These will live, THEN pass on resistance • Pretty soon, large pop’n that have this resistance • If same antibiotic used again, will increase resistance • Soon, a SUPER STRAIN of this bacteria has evolved Brain Pop link

  8. Lesson learned: • Only use antibiotics when necessary • Many strains are resistant to penicillin, the first antibiotic used • Humans are creating Super Strains with continued misuse of antibiotics • Similar occurrences with insects and insecticides

  9. What causes extinction? • Death rate higher than birth rate • Usually due to rapid env. changes • These env. changes cause major drop in pop’n size if species cannot adapt • Variation drops! • Less variation to pass on • Offspring essentially inbreeding, variation drops even more NO VARIATION = NO ADAPTIVE VALUE = EXTINCTION

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