Natural Selection and the Evidence of Evolution Section 15.1 Offset your 3 papers and make a foldable. Title the top flap the title above Title the Other flaps: What is evolution? Darwin-Travels and Influence Natural Selection Evidences—Adaptations, Fossil Evidences—Anatomical, Embyological, Biochemical

Flap 1--What is evolution? The change in populations over time.

Flap 2--Who is Charles Darwin? English scientist/naturalist whose ideas provide foundation for the theory of evolution by natural selection Sailed on HMS Beagle for 5 years studying and collecting biological and fossil specimens

Major Ports of Call… Galapagos Islands Location: Near equator, 1000km off west coast of S. America What he studied: many species of animals and plants unique to the island, but are similar elsewhere Major findings: Observations led to his consideration that species change over time

Thomas Malthus’ Influence on Darwin Proposed idea that human populations grow faster than Earth’s food supply

Darwin’s book… 1859, The Origin of Species Detailed account on his ideas and theories that support evolution

Flap 3—Natural Selection Realized organisms struggle to compete in changing environments. Many types of competition exist: Food and space Escaping predators Location of shelter

Insights into why only certain individuals survive… Traits vary among populations; these traits are inherited Breeding with others that had desirable traits produced offspring with these traits

Darwin’s Hypothesis… Artificial Selection- breeding organism with specific traits in order to produce offspring with identical traits There is force in nature that works like artificial selection

What is natural selection? Mechanism of change in populations over time

Flap 4-What are adaptations? Variation that aids an organisms chances of survival in its environment Develop in a species over many generations

Structural Adaptations Examples Teeth and Claws Protect against predators Mimicry Enables one species to resemble another Camouflage Enables species to blend with surroundings

Physiological Adaptation What are they? Changes in organism’s metabolic processes Example: After years of exposure to specific pesticides, insects and weeds have become resistant

Fossil Evidence Indirect source Provide record of early life based upon rock layers and location of fossils within them. As record becomes more complete, the sequence of evolution is clearer

earliest, most primitive bird ~145 mya Example: Archeoptryx earliest, most primitive bird ~145 mya

Flap 5-Anatomical Evidence Homologous- common evolutionary origin, features have similar structure but have different functions. Ex-bat wing and human hand

Anatomical Evidence Analogous- no common ancestor, but similar in function. Organisms like the shark and dolphin evolved sleek bodies because they live in similar environments, not because they are related.

Anatomical Evidence Vestigial- body structure in present day organism that no longer serves original purpose

Embryological Evidence The more similar the embryos through out development the closer the evolutionary relationship.

Biochemical Evidence Great table on page 403! All organisms share DNA, ATP and many enzymes among their biochemical molecules . The more changes the more time that has passed since they shared a common ancestor.