Unit 7: Evidence for Evolution

(1) Leading Ideas… Living things adapt to their environment to survive. All living things have similarities to one another. Living things rely on resources to survive. The traits living things have, allow them to survive during times of famine/disease/change. The earth has changed several times over millions of years.

(2) Darwin Biologist/Naturalist during the 1800’s. He studied similarities + differences between living organisms. He noticed that: Organisms have unique body structures, adapted to their living environment. Different types of organisms still function similarly, and/or have similar body parts. Populations are very diverse. Some animals are better suited to survive than others.

(3) Lamarck Was A Fool… Biologist/Naturalist during 1800’s (along with Darwin). He was WRONG! He thought that: Animals just magically grew body parts to adapt to their environment. That when animals make changes to themselves, they can pass on those changes to their offspring.

(4) Thomas Malthus & Humans… Economist during late 1700’s Didn’t know anything about biology/Darwin. He observed that: There is a limit to the # of organisms an area can sustain. Once the limit is too high, organisms will die (or be “weeded out”). War/Conflict, Famine and Disease ultimately control the size of a population.

(5) Hutton & Lyell on the Earth… Geologists during the late 1700’s They studied 100’s of thousands of rock evidence. They found that: Geologic structures on earth have changed over time (millions of years). The older rocks are at the bottom/center of earth. The more recent rocks/structures are near the surface.

(6) Types of Evidence… Fossil Records Comparative Anatomy Vestigial Structures Biogeography Patterns in dating and chemical composition Embryology DNA / Genetics

(7) Fossils By looking at fossils scientists can: Identify species which are extinct. Follow the path of evolution through different stages. Understand how and when certain anatomical features developed, and in which types of environments.

 WHALE VIDEO 

 FOSSIL VIDEO 

(8) Comparative Anatomy Scientists can look at the skeletal structure of different types of animals and… Look at similarities in development. Look at similarities in position and structure. Look at differences and consider causes.

(9) Types of Body Structures Homologous Structures  Features in the body part that are similar between different types of animals, because they all evolved over time from one common ancestor. Analogous Structures  Features in the body part that are similar between different types of animals, because they evolved in similar environments. Vestigial Structures  Features in the body part, found between different animals, but no longer have functions. (Proving a connection to a common ancestor.)

(10) Embryology Scientists look at development similarities between different types of animals. Shows relationship to a common ancestor.

(11) DNA / Genetics Scientists study similarities between the nitrogenous base sequences between different types of organisms. Looking at: Types of Genes Sequences within Genes The Functioning of Genes