Lesson 2 - Darwin and Evolution

What was the name of the ship Darwin too and when?

December 1831, HMS beagle (5-year trip)

On his journey, what did Darwin hypothesize?

species can change as response to their environment and habitat

Darwin proposed that…

evolution occurs by a process called natural selection

Who was Carlos Linnaeus?

father of modern taxonomy, developed nomenclature (Genus species)

Who was Jean-Baptiste Lamarck?

stated evolution was a result of inheritance of acquired characteristics, the environment can cause phenotypic change

Example of Lamarck Ideas

“if you are a really good chess player, than your kid will be a really good chess player.”

What 2 things did Darwin discover on his trip?

1. the earth is old

2. the animals found in one area can be different than those found in another area

Biogeography

the study of geographical distribution of organisms throughout the world

Evolution

the change in inheritable traits of a species over many generations or change over time

Species

a group of organisms that can reproduce and create offspring that can also reproduce

2 types of evolution

1. microevolution

2. macroevolution

Microevolution

small scale, affects a single population

Macroevolution

large scale, affects changes in species across populations

What is the mechanism Darwin proposed by which evolution occurs?

Natural Selection (survival of the fittest), descent with modification, principle by which slight variation of traits and keeping what is useful

What did he believe about environmental factors?

1. they directly impact the ability for organisms to survive

2. cause them to change phenotypes overtime

Biological fitness

the ability to survive, reproduce, and produce viable offspring

What are Darwin’s 4 Principles of Evolution?

1. Organisms exhibit variations that can be passed from one generation to another

2. Organisms compete for available resources

3. Individuals within a population differ in terms of their reproductive success

4. Organisms adapt to conditions as the environment changes

Darwin’s 1st principle: how does variation happen in a population?

DNA mutations

Darwin’s 2nd Principle: differences in phenotype may influence?

an organism’s ability to find, obtain, or utlizie its resources and the organisms ability to reproduce

Darwin’s 3rd Principle: what does it mean indiviuals in a population differ in terms of their reproductive success?

a. survival —> better reproductive success

b. Favorable traits —> more resources

Natural Selection (mechanism = how it happens)

the process by which random evolutionary changes are selected for by nature in a consistent, orderly, non-random way

Evolution of evidence (A.B.E.F.G)

Anatomy, Biochemistry, Embryology, Fossils, Geography

Homologous structures

Similar in structure/different in function, evidence of a common ancestor. E.g.: human hand, Mole foot, Bat Wing

Analogous structures

Have a similar function, evolved separately, NOT evidence of a common ancestor

Vestigal Structures

remnants of organs or structures that had a function in an early ancestor. E.g.: ostrich wings or wisdom teeth in humans

Evolution Evidence - Biochemistry

• Newest field

• All living things contain:

  • DNA (same 4 nucleotides, different sequences)

  • Proteins (same 20 amino acids,different sequences)

  • Common ancestry

Evolution Evidence - Embryology

• Identical larvae —> different adult body forms

• Similar embryos —> diverse organisms

Evolution Evidence - Fossils Example

Sperm whale has hip bones because, they used to be able to walk

Evolution Evidence - Geography

• Different locations - different species

  • Island species most closely resemble nearest mainland species

  • Populations can show variation from one island to another