How does Succession Effect the Animals?
• Pioneer plant species favor herbivores, small and large
• As the forest grows, more predators move in
• As succession continues the diversity changes
Natural Selection• If an ecosystem changes,
the animal populations have to adapt or move
• Only the animals with the characteristics to survive will populate the new ecosystem
• Animals can gain new characteristics by chance genetic mutations
Examples of Natural Selection• Darwin’s finches
– Galapagos Islands– Similar finches on each island – The finches have a unique beak
shape– Specialized for food source on it’s
island• Mountain Sheep
– Coat color and texture– Dall Sheep of Alaska– Bighorn Sheep of Rocky Mountains– Desert Sheep of Mexico
Adaptation• A trait shaped by
natural selection– Coat color or thickness– Beak shape and length
• The better suited the greater its chances of survival and reproductive success
Camouflage• Morphological
adaptations that allow animals to blend with their environment
• Prey species• Juvenile animals• Female animals
Mimicry
• Morphological adaptations that make one species look like another species
• Harmless species looking like a harmful species
• Viceroy and Monarch butterfly
• Kingsnake and coral snake
Natural Selection and Resistance• The ability of an organism to
tolerate a particular chemical designed to kill it– Herbicides
• Roundup Resistant weeds– Pesticides
• Colorado Potato Beetle– Antibiotics
• Methicillin-resistant Staphylococcus aureus (MRSA)
Artificial SelectionThe selective breeding of organisms by humans
for specific characteristics
Three Types of Natural Selection
StabilizingDirectionalDisruptive
• Remember– These are examples of different populations of
the same species
Stabilizing Selection
• Selection against both extremes
Directional Selection
• Selection against one extreme
Disruptive Selection
• Selection against the mean
• Splits population into two groups