1. Biological Evolution

2. Diversity and Relationships
Charles Darwin ( ) was an English scientist who sailed all over the world on the HMS Beagle.
Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the world.
Emu
Australia
Ostrich
Africa
Rhea
South America

3. Species Can Vary Globally, Locally and Over Time…
Darwin noticed that the tortoises in the Galapagos Islands showed different shaped shells
From these observations he realized that different, yet related animal species often occupied different habitats within a local area.

4. The modern armadillo is similar to the ancient glyptodont
On his journey, Darwin also collected fossils and he noticed that some fossils of extinct animals were similar to living species
The modern armadillo is similar to the ancient glyptodont
.5m
3 m

5. What does it all mean?
When Darwin returned home he kept thinking about his findings and what it meant. How do the separate yet similar species arise and why are they found in specific locations?
In order to draw his final conclusions he used ideas from a few other scientists at the time:
Hutton & Lyell
Lamarck
Thomas Malthus

6. An Ancient, Changing Earth
Hutton & Lyell concluded that Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present.
These changes to Earth over time led Darwin to conclude that changes to life over time must be possible as well.

7. Lamarck’s Evolutionary Hypothesis
Lamarck suggested that organisms could change during their lifetimes by selectively using or not using various parts of their bodies. He also suggested that individuals could pass these acquired traits to their offspring leading to changes in a specie over time.
False, but did have the first notion that species are not fixed- they can change over time.

8. Population Growth
In 1798 and English economist named Thomas Malthus noticed that more humans were being brought into the population that were dying.
He reasoned that if the population grew unchecked then there wouldn’t be enough living space or food for everyone.
Things that could limit the number were war, famine, and disease. Darwin realized that this same idea could apply to other species.
More offspring are produced than survive so what makes one offspring survive over another?

9. Piecing it all Together
From reading the works of previous scientists, Darwin realized that organisms can change over time, or evolve.
How It works- 4 Principles of Natural Selection:
1. Overproduction of offspring: The more eggs you lay, the greater chance that some will survive.
2. Variation & Adaptation: The eggs that do hatch and survive must have a heritable traits that makes them more ‘fit’ in their environment.
Physical (mimicry or camoflauge)
Behavioral

10. Continued… How It works- 4 Principles of Natural Selection:
3. Survival of the Fittest: In any given environment, certain traits will be more successful that others. The ones with that trait will survive to reproduce and pass down that successful trait to their offspring.
4. Descent with Modification: We are all descended from our ancestors who came from theirs and so on down the line. Darwin concluded that all species, living and extinct descended from a common ancestor.

11. Evidence of Evolution
1. Paleontology: Studying fossils and tracing the evolution of modern species back to their extinct common ancestors.
2. Anatomy: Different species have similar bone structure leading to the conclusion that they inherited the basic version of that structure from a common ancestor.
Homologous Structures- similar structures found in species with a common ancestor that have adapted to different uses.

12. Analogous Structures- body parts on different species that share common function but not structure.
Vestigial Structures- Inherited body parts that have limited or no function in the present organism.
Ex. Hipbones in the bottlenose dolphin
3. Embryology: Similar patterns of embryological development provide further evidence that organisms have descended from a common ancestor.
In different species, homologous structures develop from the same clump of embryonic cells.

13. Evidence of Evolution… continued
4. Biochemistry: All living things possess a genetic code made of DNA. It contains genes that instruct the synthesis of proteins and it is passed down to the offspring.
There are homologous genes found in different species, for example—
The Hox gene. Determines an embryos axis (which end is up/down), and where the types of limbs should form. This same gene is found in almost all multicellular organisms.

14. 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.
Directional Selection- Favors one extreme
Stabilizing- Favors the middle form
Disruptive- Favors both extremes
2. Gene Flow - the movement of genes into or out of a population.

15. 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.

16. 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
1. Gradualism: slow, steady changes over many years
2. Punctuated Equilibrium: Long period of no change followed by a quick change to the specie

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

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

19. 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.

20. 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.

21. 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

22. How Do We Organize 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.
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

23. 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

24. Changing Ideas About Kingdoms
Kingdoms of Life, 1700s–1990s
First Introduced
Names of Kingdoms
1700s
Plantae
Animalia
Late 1800s
Protista
Plantae
Animalia
1950s
Monera
Protista
Fungi
Plantae
Animalia
Tell students that the process of identifying and naming all known organisms, living and extinct, is a huge first step toward the goal of systematics. Yet naming organisms is only part of the work. The real challenge is to group everything, from bacteria to dinosaurs to blue whales, in a way that reflects their evolutionary relationships. Over the years, Linnaeus’s original scheme for naming organisms has changed as new discoveries have been made. That change continues today as studies at the molecular level accumulate new data.
Direct students’ attention to the table.
Explain that, during Linnaeus’s time, the only known differences among living things were the fundamental characteristics that separated animals from plants. Animals were organisms that moved from place to place and used food for energy. Plants were green organisms that generally did not move and got their energy from the sun. As biologists learned more about the natural world, they realized that Linnaeus’s two kingdoms—Animalia and Plantae—did not reflect the full diversity of life.
Click to reveal the rest of the table.
Explain that classification systems have changed dramatically since Linnaeus’s time. And hypotheses about relationships among organisms are still changing today as new data are gathered.
Ask: Can you identify the difference between the kingdoms of the five-kingdom system and the kingdoms of the six-kingdom system? Explain.
Answer: In the five-kingdom system, all bacteria were included in one kingdom, Monera. In the six-kingdom system, bacteria are split into two kingdoms, Eubacteria and Archaebacteria.
Discuss how advanced technology, such as DNA analysis, is providing new information that has caused biologists to rethink how organisms should be classified. As researchers began to study microorganisms, they discovered that single-celled organisms were significantly different from plants and animals. At first, all microorganisms were placed in their own kingdom, named Protista. Then yeasts and molds, along with mushrooms, were placed in their own kingdom, Fungi. Later still, scientists realized that bacteria lack the nuclei, mitochondria, and chloroplasts found in other forms of life. All prokaryotes (bacteria) were placed in yet another new kingdom, Monera. Single-celled eukaryotic organisms remained in the kingdom Protista. This process produced five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia.
By the 1990s, researchers had learned a great deal about the genetics and biochemistry of bacteria. That knowledge made clear that the organisms in kingdom Monera were actually two genetically and biochemically different groups. As a result, the monerans were separated into two kingdoms, Eubacteria and Archaebacteria, bringing the total number of kingdoms to six. The six-kingdom system of classification includes the kingdoms Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia.
Call on volunteers to name organisms that are members of each of the six kingdoms.
1990s
Eubacteria
Archaebacteria
Protista
Fungi
Plantae
Animalia

25. Kingdom Characteristics

26. 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

27. 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

28. 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 ( )