Download Natural Selection

Name: __________________________
Class: _______
Date: _________
Natural Selection
• ___________________________= any trait that aids the chances of survival and reproduction
of an organism.
• Two types: ___________________and _____________________
o STRUCTURAL ADAPTATIONS arise over____________________:
� ________________= provides protection for an organism by enabling it to copy the
appearance of another species.
� _______________________= enables an organism to blend in with its surroundings
• more likely to escape predators and survive to reproduce
Coral snake-venom
Scarlet king snake- non-venomous
Example of Natural Selection:
• ____________ colored pepper moths less noticeable on lichen covered trees
• ____________ kills lichens and uncovers darker tree trunks
o PHYSIOLOGICAL ADAPTATIONS can ______________________
� Changes in an organism _____________________________
� Ex: ___________- was considered 50 years ago as a wonder drug b/c it could kill many types
of disease-causing ___________.
• Now penicillin is not as effective as it used to be because many species of bacteria have
___________ physiological adaptations that make them __________ to penicillin
� Ex: insects/ weeds have been selected for physiological resistance to ___________ used in
pesticides.
VI. Evidence for Evolution:
1. ______________________
• nucleotide sequencing studies are used to indicate levels of ______________among species
within major taxonomic groups
2. _____________________
• fossil records show how organisms have ___________ over time (millions of years)
3. ________________________________________:
• ___________________________________= Similarities in structure and __________ —
likeness indicates a genetic relationship through a common ancestor.
• Ex: ___________ among the bones of the forelimb. : Although these structures show
considerable differences in form and ___________, the same basic bones are present in the
forelimbs of humans, cats, bats, porpoises, and horses.
4. ________________________________________ = any body structure that is ________ in
function in a living organism but may have been used in an ancestor.
• Examples:
• pelvis in snakes
• external ears and pelvis in whales
• Humans: appendix, ear muscles, nictitating membrane, wisdom teeth.
5. ________________________________________: Development of the phylum- in the
embryonic stage it is difficult to distinguish fish, amphibians, reptiles, birds, and mammals.