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FUN FACT: How long does evolution take?. Bacteria – can reproduce every 20 minutes…so after 2 days (48 hours), there has already been 144 generations born!!! (That’s 2.2 X 10 43 bacteria born!) That’s why bacteria can evolve in a shorter time period.
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FUN FACT: How long does evolution take? Bacteria – can reproduce every 20 minutes…so after 2 days (48 hours), there has already been 144 generations born!!! (That’s 2.2 X 1043 bacteria born!) That’s why bacteria can evolve in a shorter time period. Humans – In order to have 144 generations (reproducing every 25 years), it will take us 3,600 years!! That’s why it takes so much longer for humans to evolve.
DARWIN’S CURIOSITY…. • LED HIM TO THE SCIENTIFIC THEORY OF EVOLUTION BY WAY OF: NATURAL SELECTION!!
Wild mustard & domestic cruciform vegetables Darwin knew about artificial selection, and argued that a similar process must occur in nature. Domestic dogs Wild canis
NATURAL SELECTION ORGANISMS THAT ARE BETTER ADAPTED SURVIVE. THEY REPRODUCE AND PASS ON THEIR SUCCESSFUL TRAITS TO THEIR OFFSPRING.
WHAT CAUSES NATURAL SELECTION? 1. OVERPRODUCTION =MORE OFFSPRING PRODUCED BY THE SPECIES THAN CAN LIVE DUE TO LIMITED RESOURCES *this way when some die, hopefully at least one or a few will live
OVERPRODUCTION LEADS TO…. 2. COMPETITION FOR RESOURCES Living space Food Water
What else affects Natural Selection? GENETIC VARIATIONS MEMBERS OF THE SAME SPECIES DIFFER FROM EACHOTHER
WHAT DO VARIATIONS IN SPECIES RESULT FROM?? MUTATIONS in GENES- RANDOM CHANGES IN DNA THAT LEAD TO NEW TRAITS THESE CAN BE PASSED ON TO THE NEXT GENERATION
What do variations in species result from?? SEXUAL REPRODUCTION Makes new genetic combinations and traits when mixing DNA
Organisms with variations that are BEST SUITED to the environment can out-compete others… This means they will be able to survive longer and have more offspring
HAVING MORE OFFSPRING MEANS… • PASSING YOUR GENES (which code for traits) ON TO MORE INDIVIDUALS
OVER GENERATIONS… individuals have more and more helpful variations individuals have less and less harmful variations
HOW DO NEW SPECIES FORM?? GEOLOGICAL ISOLATION =species separated by a barrier into 2 different areas
What are barriers?? • BARRIERS CAN INCLUDE: OCEANS ISLANDS RIVERS MOUNTAINS VOLCANOES
Over generations… • Each population changes to adapt to its environment Ursus maritimus Ursus americanus Ursus arctos
THE POPULATIONS CHANGE SO MUCH THAT… if the barrier is removed, the individuals from the different groups cannot mate with each other at this point, they are considered separate species.