Use the dichotomous key to determine the scientific name of Bird Y

Phylogeny Practice Questions 1. Name 2 types of evidence that can be used to construct a phylogenetic tree. Which type is better? 2. Are A and B more closely related than C and D? Explain 3. What number is labeling the common ancestor of A, B, C, and D 4. What number is labeling the common ancestor of C and D

Evidence for Evolution Homologous structures- structures that are similar in structure, but not function. They suggest a common ancestor between distantly related species DNA/Molecular Evidence- provides quantitative evidence about evolutionary relatedness. The less differences in DNA, the more closely related something is Fossils- show the existence of diverse organisms from billions of years ago. Show similar structures to organisms today (ex: bird and dinosaur)

Natural Selection Organisms with advantageous traits in their specific environment will survive better, reproduce more, and pass that trait on. Overtime, the advantageous traits will become more common in a population Organisms with harmful traits in their specific environment will be more likely to die before passing their traits on, so those traits will become less common over time

Darwin’s Conclusions Variation exists in a population The variation is inherited and passed on from parent to offspring Some of that variation gives an organisms an advantage The organisms with advantageous traits are more likely to survive and reproduce more passing those traits on

Natural Selection and Antibiotic Resistance

Steps of Antibiotic Resistance 1. A population of bacteria replicate quickly, and naturally, mutations occur. Some of those mutations may code for proteins that create a resistant bacteria 2. Once antibacterial products are given to the bacteria, the resistant bacteria have a strong advantage 3. The resistant bacteria survive the antibiotics, reproduce, and pass their resistant genes on 4. Over time, the antibiotic will kill off ‘sensitive’ bacteria, leaving only resistant bacteria to remain

How does overuse led to antibiotic resistance? The more the bacteria on a surface or on your body are exposed to an antibiotic, the greater the selection pressure is to carry resistant genes If a population of bacteria is never exposed to antibiotics, then being resistant gives them no advantage The more antibiotic exposure you have, the more times you are killing off the ‘weaker/sensitive’ bacteria cells, and allowing the resistance ones to grow

Steps of Speciation 1. A species gets isolated from each other geographically into location A and location B 2. Location A is drastically different from location B, so different traits are favored by natural selection in each location 3. Random mutations in the species occur in both locations, but are selected for differently 4. Overtime, the species become more and more different due to different traits being advantageous in their different locations 5. After many many years, the species become so different they are no longer able to interbreed

Geographical Isolation Volcanic eruption Migration to an island Flood forming new river Earthquake Man-made barriers (roads, buildings etc.)

Dichotomous Keys

Phylogenetics Can be built by DNA evidence, molecular evidence (like protein sequences), or anatomical features (what they look like) Puts species in order of relatedness The length of the line represents the evolutionary time The longer the line between two species, the longer ago a common ancestor existed (i.e. the less related they are)