1. Biological Evolution
Unity and diversity

2. HS-LS4-4 Construct an explanation based on evidence for how natural selection leads to adaption of populations.
Clarification Statement: Emphasis is on using data to provide evidence for how specific biotic and abiotic differences in ecosystems (such as ranges of seasonal temperature, long-term climate change, acidity, light, geographic barriers, or evolution of other organisms) contribute to a change in gene frequency over time, leading to adaptation of populations.

3. Elements of Natural Selection
Process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genotype, or genetic constitution
Struggle for existence
Individual phenotypic variation
Inheritance
Some phenotypes better adapted
Struggle for existence: Reproduction often exceeds the population carrying capacity. Not all individuals will be able to contribute the same number of offspring to the next generation.
Individual phenotypic variation: traits differ among individuals of a population
Inheritance: traits are passed on to offspring
Some phenotypes are better adapted: certain phenotypes are better suited to particular environments; individuals that possess the better suited phenotypes are more likely to survive and reproduce

4. Microevolution
Microevolution is a change in gene frequency within a population
Change might come about because natural selection favored the gene, because the population received new immigrants carrying the gene, because genes mutated, or because of random genetic drift from one generation to the next
Examples of microevolution
Evolution of resistance — of pests to pesticides, weeds to herbicides, and pathogens to medicines 
House sparrows were introduced to NA in Sparrows in colder places are now generally larger than sparrows in warmer locales.
Since introduction, sparrows have evolved different characteristics in different locations. Sparrow populations in the north are larger-bodied than sparrow populations in the south. This divergence in populations is probably at least partly a result of natural selection: larger-bodied birds can often survive lower temperatures than smaller-bodied birds can. Colder weather in the north probably selects for larger-bodied birds.

5. Microevolution to Macroevolution
Microevolution happens on a small time scale — from one generation to the next
Small changes build up over the course of millions of years, they translate into evolution on a grand scale — in other words, macroevolution
The four basic evolutionary mechanisms — mutation, migration, genetic drift, non-random mating, and natural selection — can produce major evolutionary change if given enough time

6. Macroevolution Evolution above the species level
Macroevolution required that we zoom out on the tree of life
Macroevolution encompasses the grandest trends and transformations in evolution, such as the origin of mammals and the radiation of flowering plants
Macro-evolutionary patterns are generally what we see when we look at the large-scale history of life.

7. Macroevolution Patterns in Macroevolution Stasis Character change
Lineage splitting
Extinction

8. Speciation
Species: a group of individuals that actually or potentially interbreed in nature. In this sense, a species is the biggest gene pool possible under natural conditions
The definition of a species as a group of interbreeding individuals-- cannot be easily applied to organisms that reproduce only or mainly asexually. (Bacteria)
Many plants, and some animals, form hybrids in nature

9. Speciation
Lineage-splitting event that produces two or more separate species
Causes of speciation
Geographic Isolation
Reduction of Gene Flow
Geographic isolation: It doesn’t even need to be a physical barrier like a river that separates two or more groups of organisms—it might just be unfavorable habitat between the two populations that keeps them from mating with one another.
Reduction in gene flow: no specific extrinsic barrier to gene flow. Imagine a situation in which a population extends over a broad geographic range, and mating throughout the population is not random. Individuals in the far west would have zero chance of mating with individuals in the far eastern end of the range. So we have reduced gene flow, but not total isolation.   Speciation would probably also require different selective pressures at opposite ends of the range, which would alter gene frequencies in groups at different ends of the range so much that they would not be able to mate if they were reunited.
Broad geographic range limits gene flow– different selective pressures at ends of range

10. Predation as a Factor in Evolution
Predators take prey in a non-random fashion
Those with features/traits that make them less likely to be preyed upon are more likely to survive and reproduce…. If those traits are inherited by the offspring evolution can take place (Rock Pocket Mice)
Keep in mind the generation and presence of variation of traits in a population is random, but the selection (Natural Selection) is not random
Small differences over long periods of time result in macroevolution and even speciation

11. Sources http://evolution.berkeley.edu/evosite/evo101/
BioInteractive Howard Hughes Medical Institute

17. Homologies must be made carefully and must always refer to the level of organization being compared.
Homologies must be made carefully and must always refer to the level of organization being compared. For instance, the bird wing and the bat wing are homologous as forelimbs, but not as wings. In other words, they share a common underlying structure of forelimb bones because birds and mammals share a common ancestry. However, the bird wing developed independently from the bat wing. Bats descended from a long line of nonwinged mammals, and the structure of the bat wing is markedly different from that of a bird wing.
Homologies of structure among a human arm, a seal forelimb, a bird wing, and a bat wing; homologous supporting structures are shown in the same color. All four are homologous as forelimbs and were derived from a common tetrapod ancestor. The adaptations of bird and bat forelimbs to flight, however, evolved independently of each other, after the two lineages diverged from their common ancestor. Therefore, as wings they are not homologous, but analogous

18. Embryonic homology of the fish gill cartilage, the reptilian jaw, and the mammalian middle ear 
Gill arches of jawless (agnathan) fishes became modified to form the jaw of the jawed fishes
In the jawless fishes, a series of gills opened behind the jawless mouth
When the gill slits became supported by cartilaginous elements, the first set of these gill supports surrounded the mouth to form the jaw
Jaws are modified gill supports
One of the most celebrated cases of embryonic homology is that of the fish gill cartilage, the reptilian jaw, and the mammalian middle ear (reviewed in Gould 1990). First, the gill arches of jawless (agnathan) fishes became modified to form the jaw of the jawed fishes. In the jawless fishes, a series of gills opened behind the jawless mouth. When the gill slits became supported by cartilaginous elements, the first set of these gill supports surrounded the mouth to form the jaw. There is ample evidence that jaws are modified gill supports. First, both these sets of bones are made from neural crest cells. (Most other bones come from mesodermal tissue.) Second, both structures form from upper and lower bars that bend forward and are hinged in the middle. Third, the jaw musculature seems to be homologous to the original gill support musculature. Thus, the vertebrate jaw appears to be homologous to the gill arches of jawless fishes.

19. Jaw structure homology
Both these sets of bones are made from neural crest cells
Both structures form from upper and lower bars that bend forward and are hinged in the middle
The jaw musculature seems to be homologous to the original gill support musculature
Thus, the vertebrate jaw appears to be homologous to the gill arches of jawless fishes

20. Homology
The upper portion of the second embryonic arch supporting the gill became the hyomandibular bone of jawed fishes
This element supports the skull and links the jaw to the cranium 
 The upper portion of the second embryonic arch supporting the gill became the hyomandibular bone of jawed fishes. This element supports the skull and links the jaw to the cranium. As vertebrates came up onto land, they had a new problem: how to hear in a medium as thin as air. The hyomandibular bone happens to be near the otic (ear) capsule, and bony material is excellent for transmitting sound. Thus, while still functioning as a cranial brace, the hyomandibular bone of the first amphibians also began functioning as a sound transducer (Clack 1989). As the terrestrial vertebrates altered their locomotion, jaw structure, and posture, the cranium became firmly attached to the rest of the skull and did not need the hyomandibular brace. The hyomandibular bone then seems to have become specialized into the stapes bone of the middle ear. What had been this bone's secondary function became its primary function.

21. Jaw structure in the fish, reptile, and mammal
Jaw structure in the fish, reptile, and mammal. (A) Homologies of the jaws and gill arches as seen in the skull of the Paleozoic shark Cobeledus aculentes. (B) Lateral view of an alligator skull. The articular portion of the lower jaw articulates with the quadrate bone of the skull. (C) Lateral view of a human skull, showing the junction of the lower jaw with the squamosal (temporal) region of the skull. In mammals, the quadrate becomes the incus of the middle ear. The articular bone retains its contact with the quadrate, becoming the malleus of the middle ear.
Jaw structure in the fish, reptile, and mammal. (A) Homologies of the jaws and gill arches as seen in the skull of the Paleozoic shark Cobeledus aculentes. (B) Lateral view of an alligator skull. The articular portion of the lower jaw articulates with the quadrate bone of the skull. (C) Lateral view of a human skull, showing the junction of the lower jaw with the squamosal (temporal) region of the skull. In mammals, the quadrate becomes internalized to form the incus of the middle ear. The articular bone retains its contact with the quadrate, becoming the malleus of the middle ear. (A after Zangerl and Williams 1975.)