Evolution 4 Natural selection.notebook

1

February 06, 2018

Feb 5­10:48 AM

Aim: Explain the mechanism of evolution by natural selection.

Hw. Do all questions in the handout distributed in class.study for quiz Friday

1. Role of theories

2. How do we know evolution happens

3. Natural selection notes.

4. Start working on review package.

https://www.youtube.com/watch?v=85diEXbJBIk

https://ny.pbslearningmedia.org/resource/tdc02.sci.life.evo.howreally/evolving­ideas­how­does­evolution­really­work/#.WnhWvrynEdU

https://ny.pbslearningmedia.org/resource/tdc02.sci.life.evo.howhappens/evolving­ideas­how­do­we­know­evolution­happens/?#.WnhXP7ynEdU

Feb 6­6:23 PM

Natural selection: Theory of evolution described by Charles Darwin it includes the following processes:

• Variability: Darwin could not explain it at his time. It depends of all the different genes present in a population at a given time. The different alleles are the result of mutations.

• Survival of the fittest: Competition takes place between organisms of the same species as an organism develops. Adults compete for mates and food; also compete with other species for food and space. The best fit survive. (pics next slide)

• Sexual reproduction: Successful organisms get to sexually reproduce and after fertilization produce offspring that could inherit the successful traits.

• Environmental change:Condition in the environment that acts as a selective agent of a trait. (Temperature change, decrease in food, a parasite, a predator, etc)

• Geologic time: Thousands of millions of years with active changes that shaped and continue shaping the evolution of life on earth.

All these processes are necessary for species to evolve.

scientistsscientists

Evolution 4 Natural selection.notebook

2

February 06, 2018

Feb 5­11:17 AM

Examples of competition among organisms of the same species

competition for light.

Feb 5­8:02 AM

Self quiz:

• 1 Age of the planet and conditions (inorganic molecules). About 4.5 billion years. It was hot, no liquid water filled with poisonous gases. It was lifeless. • 2 The observable fact that living organisms change through time as they adapt to changes in the environment. Evolution:

• 3 Name four things that show or prove the fact that evolution takes place.Fossils, vestigial structures, homologous structures, comparative embryology, and DNA comparison.

• 4 Any kind of remains from living things that inhabited the earth in the past. Fossils

• 5 Structures that do not have any function in a organism that remain from ancestors in the evolution of a species. Vestigial structures.

• 6 Structures that have similar function and anatomy in related species, which suggest that they have a common ancestor.Homologous structures.

• 7 Study of embryos of related speciescomparative embryology

• 8 Darwin's theory of evolutionNatural selection

• 9 Lamarck's theory of evolutionInheritance of acquired characteristics.

• 10 The five conditions that make possible evolution by Natural selectionGenetic variability, competition (survival of the fittest), sexual reproduction, environmental change or challenge and time (geologic time).

• 11 All the multiple alleles that exist in a given populationGenetic variability

• 12 The origin of genetic variabilitymutations