1. Biological Evolution

2. Diversity and Relationships
Charles Darwin ( ) was an English scientist who sailed all over the world on the HMS Beagle.
Darwin became curious about the diverse creatures that he saw and the possible relationships between them.

3. Natural Selection
Natural Selection occurs when organisms with certain traits survive, reproduce, and pass on those traits to the next generation.
Ex: A faster fish may be better suited for escaping predators and live to produce offspring with that same variation
This is often described as “Survival of the Fittest”

4. Three Principles of Natural Selection
Overproduction of offspring – having many offspring raises the chance that some will survive
Variation and Adaptation
A heritable trait that increases and organisms ability to survive is an adaptation.
Survival of the ‘Fittest’
Those best suited for an environment will survive and reproduce.
Descent with Modification
More individuals will have the successful traits in future generations, as long as those traits are beneficial.

5. Examples of Variations & Adaptations

6. Diversity within a Species
All the genes, including different alleles, in a given population is called the “gene pool”
Diversity within a species makes it more likely that the right adaptation could be present – therefore, an increase in diversity increases its chances of survival
**How do you get diversity in a population…???**

7. 5 Factors That Cause Diversity
Genetic Drift - the random change in the frequency of alleles of a population over time. Due to chance, rare alleles in a population will become eliminated; other alleles will increase in frequency and become fixed.
2. Gene Flow - the movement of genes into or out of a population.

8. 5 Factors That Can Affect Genetic Variability
Non-random Mating – Mating among individuals with favorable traits
» such as coloration in plants and animals,
competitive strength, courting behaviors etc.
Mutations – changes in DNA
increase the frequencies and types of allele
5. Natural Selection – Since only the ‘fittest’ organisms survive, they will influence which genes are passed down to future generations.

9. Changes in a Specie over Time Will Lead To…. EVOLUTION
Speciation is the process of forming a new species by biological evolution from a preexisting species

10. Patterns of Evolution
Adaptive Radiation/Divergent Evolution: - a number of different species diverge (split-off) from a common ancestor. in different niches.

11. Patterns of Evolution
Convergent Evolution – Unrelated organisms in similar environments may evolve adaptations to similar niches.

12. Patterns of Evolution
Coevolution - when two or more species living in close proximity change in response to each other. The evolution of one species may affect the evolution of the other.

13. Patterns of Evolution
Extinction - the elimination of a species often occurring when a species cannot adapt to a change in its environment. This can be gradual or rapid.
Gradual extinction - occurs at a slow rate and may be due to other organisms, changes in climate, or natural disasters.
Mass extinction - occurs when a catastrophic event changes the environment very suddenly (such as a massive volcanic eruption, or a meteor hitting the earth causing massive climatic changes). It is often impossible for a species to adapt to rapid and extreme environmental changes.

14. Evidence of Biological Evolution
The changes in inherited traits in a species over time is called biological evolution.
Microevolution occurs on a small scale affecting a single population
Macroevolution occurs on a large scale affecting changes in species across populations
The species we see today evolved from species of former periods of time.
Other Evidence of Evolution
Paleontology
Anatomy
Embryology
Biochemistry

15. Paleontology Paleontology is the study of prehistoric life
Fossils are preserved remains of organisms that lived many years ago
The fossil record provides evidence of life forms and environments and supports evolutionary relationships by showing the similarities between current species and ancient species.

16. Anatomy
Anatomy is the study of the structures of organisms
1. Homologous Structures have similar characteristics resulting from sharing common ancestry
The greater the numbers of shared homologous structures between two species, the more closely the species are related2.
2. Analogous Structures reveal that species living in different locations under similar ecological conditions may evolve similar
ex. Butterfly and Bird Wings
3. Vestigial Structures serve little or no function in the organism
The vestigial organs of one specie are often homologous with structures in a related specie that still uses the organ.

17. Embryology Embryology is the study of embryo development in organisms
The could include pre-birth, pre-hatching, or pre-germination
Studying the structures of embryos can lead to clues of possible ancestors
The embryos of fish, reptiles, birds, and mammals all have a tail and gill slits even though they may not exist on the mature organism

18. Biochemistry
The more similar the DNA and amino acid sequences in proteins of two species, the more likely they are to have diverged from a common ancestor
All citrus trees can produce citric acid and therefore may have developed from a common ancestor
The study of the ability of different species to synthesize similar substances is called comparative biochemistry

19. Evolutionary Relationships
A Phylogenetic Tree shows the relationship of different organisms believed to have a common ancestor based on taxa (groups)
Branches from an intersection show those with a common ancestor
You can see that the snail, earthworm and insect have a more recent common ancestor than the snail and sea star
Time

20. Classification of Life
All living things can be classified as belonging to one of 3 Domains
Bacteria - Archaea - Eukarya
All living things can be classified as belonging to one of the 6 Kingdoms of Life
Archaeabacteria
Eubacteria
Protista
Plantae
Fungi
Animalia

21. How Do We Name all These Organisms?
Biologists identify and organize organisms through Taxonomy- a classification of organisms based on shared characteristics.
To work, the system needs to be universal across the scientific community and everyone needs to follow the same rule for naming a specie.
At first, scientists tried to use Greek or Latin but the interpretations often didn’t work well.
Carolus Linnaeus developed a two-part naming system called Binomial Nomenclature.
It uses the Genus and Specie of an organism to identify it.
EX: Polar Bear would be called Ursus maritimus

22. Organism Kingdom Animalia Phylum Chordata Class Mammalia Order
Red Fox
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Carnivera
Rodentia
Family
Felidae
Canidae
Geomyidae
Genus
Felis
Vulpus
Canis
Thomomys
Species
domesticus
fulva
familiaris
lupus
bottae

23. Kingdom Characteristics

24. Dichotomous Key 1. a. wings covered by an exoskeleton ………go to step 2
A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, animals, or rocks. Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.
1. a. wings covered by an exoskeleton ………go to step 2
b. wings not covered by an exoskeleton ……….go to step 3
2. a. body has a round shape ……….ladybug
b. body has an elongated shape ……….grasshopper
3. a. wings point out from the side of the body ……….dragonfly
b. wings point to the posterior of the body ……….housefly

25. Hardy-Weinberg Principle
When there is no change in the allele frequencies in a species, the population is in genetic equilibrium.
This concept is known as the Hardy-Weinberg Principle. To sustain equilibrium, the must be:
A very large population with no genetic drift
No movement into or out of the population
Random mating
No mutations with the gene pool
No natural selection
Godfrey Hardy ( )
Wilhelm Weinberg ( )