ADAPTATIONS GRADUALISM VS PUNCTUATED EQUILIBRIUM NATURAL SELECTION The
ADAPTATIONS
GRADUALISM VS PUNCTUATED EQUILIBRIUM
NATURAL SELECTION � The theory of natural selection was developed by ____________ Charles Darwin ___ and first presented in his The Origin of book ____________, Species published in 1859.
THE THEORY OF NATURAL SELECTION 1. There is a struggle for existence among organisms.
THE THEORY OF NATURAL SELECTION 2. There is physical and behavioral variation in living organisms (even within the species level).
THE THEORY OF NATURAL SELECTION 3. Organisms with higher fitness (more helpful adaptations) are more likely to survive: “Survival of the Fittest. ”
NATURAL SELECTION 4. Over time, a natural selection will ensure that certain characteristics appear more and more often as they are passed through generations. Entire species can change over time in this way.
NATURAL SELECTION � Common descent/Descent with modification: Every living species has descended, with changes, from other species over time.
WHY ARE HUMANS SUCCESSFUL? 1. Walking upright—can use arms and see farther 3. Big brains for being awesome 2. Opposable thumbs for grasping
WHY CAN’T HUMANS EVOLVE TO COPE WITH OUR NEW ENVIRONMENTAL CONDITIONS? 1. 2. Genes for new traits have to already be present in a population’s gene pool through random mutation. Our generation times are too long to keep up with rapidly changing conditions—we aren’t fruit flies or bacteria! Human
MYTHS ABOUT EVOLUTION (THESE ARE UNTRUE STATEMENTS) 1. 2. 3. “Fitness” means strongest, fastest, or biggest. Organisms develop new traits in order to help them in their environment. Evolution is a constant progression towards some perfect ideal.
GEOLOGICAL PROCESSES AFFECT EVOLUTION 1. Locations of continents influence climate and habitats
GEOLOGICAL PROCESSES AFFECT EVOLUTION 2. Movement of continents allow for dispersal, speciation, extinction
3. Earthquakes can isolate populations, leading to speciation
4. Volcanoes can destroy habitat and cause extinction
5. Asteroid impacts can cause widespread extinction, climate
CLIMATE CHANGE AFFECTS EVOLUTION 6. Ice ages/warming periods cause migration, extinction, new niches
ENVIRONMENTAL CHANGES, EITHER SUDDEN OR GRADUAL, MAY THREATEN A SPECIES’ SURVIVAL, REQUIRING INDIVIDUALS TO ALTER BEHAVIORS, MOVE, OR PERISH. With your buddy/group… come up with a SUDDEN and a GRADUAL example…. Be prepared to chare with class Sudden environmental change example Individuals to alter behaviors, move, or perish (example) Gradual environmental change example Individuals to alter behaviors, move, or perish (example)
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