Biology 211 (2) Week 1 KEY!

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1 Biology 211 (2) Week 1 KEY Chapter 1 KEY FIGURES: 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 VOCABULARY: Adaptation: a trait that increases the fitness Cells: a developed, system bound with a thin outer layer made of plasma that contains organelles; able to reproduce/replicate Energy: The ability to do work, required to live Fitness: the ability to produce healthy offspring (High fitness=many healthy offspring) Hypothesis: A testable statement meant to explain an observation/specific questions Natural selection: When a group within a population carries different traits that will benefit the offspring to survive better, the one s without the trait will eventually die out, leading to a change in evolution Artificial selection: When humans cause changes of a species to produce the most offspring possible (Ex: Corn) Control group: The group of organisms or samples in an experiment that are unchanged/not tampered with Eukaryotes: Any organisms whose cell contains a nucleus, as well as multiple membrane bound organelles Genus: A closely related group of species (The first part of the Scientific Name) Information: Code stored within genes, must be able to respond to information and have genes to be living Null hypothesis: When the initial hypothesis is found incorrect, this null hypothesis states what should be tested instead Cell theory: Cells make up all organisms; all cells come from other cells Domain: A taxonomic category (Bacteria, Archaea, Eukarya) Evolution: a change over time of a species characteristics to adapt as best as possible with their surrounding environment Heritable: Traits able to be passed on to the next generation LUCA: Last Universal Common Ancestor Phylogeny: The relationships between organisms and their evolutionary history

2 Phylum: A taxonomic category referring to major lineages in the domains Prokaryotes: An organism who s cell does not contain a nucleus (Also the first form of life to appear) Species: A population/group of individuals that share similar looks, behavior, genes, etc; Also, the second part of a scientific name Population: A group of the same species living together at the same time Replication: The ability to reproduce/ make more of itself, required to be living Spontaneous generation: The theory which stated that living things were able to randomly appear Prediction: A result able to be measured and is based on the hypothesis of an experiment. A correct prediction provides support towards a hypothesis. Speciation: When a single species evolves into two separate species Taxon: Any named group of organisms Taxonomy: The classification and naming of organisms Theory: An explanation to anything needing reasoning, supported by multiple studies. Theory of evolution: The studied suggestion that all species come from a common ancestry, and that all species modify from generation to generation. KEY CONCEPTS: 1. What are the five characteristics of life? RICEE Energy: Must use energy (plants absorb sunlight; animals ingest food) Cells: All organisms are made up of membrane bound cells Information: Must be able to transfer the information and receive (Genetics; DNA, Epigenetic s; Genes you are expressing pattern of expression, Homeostasis; Keep the body or individual cell conducive to life/ the same [Ex: Metabolism]) Replication: Reproduction (Offspring, A cut healing) Evolution:(Every living thing evolves- between generation to generation 2. What is the difference between hypotheses and theories? 1. A hypothesis is a testable statement meant to explain a phenomenon, while a theory is an explanation for a phenomenon. When scientists state theory, they refer to a proposed explanation for broad patterns, while stating a hypothesis for more narrow focused questions. 3. What are the two components of a biological theory? What are the two main theories in biology? State their two components 1. Pattern: something that occurs in the natural world, Process: Responsible for creating the pattern 2. Cell theory: Pattern 3. Theory of Evolution by Natural Selection: Pattern (Common Ancestry), Process (Decent with modification) 4. Describe the Cell Theory. Did this theory support or challenge the idea of spontaneous generation? 1. The cell theory states that all cells must come from other cells, and all organisms consist of cells. Another part of the cell theory is that the smallest living thing is a cell.

3 2. The cell theory challenged the concept of spontaneous generation by stating that cells must derive from preexisting cells. Spontaneous generation suggested that cells were able to randomly appear. 5. Natural selection occurs at the hierarchical level of, while evolution occurs at the level of. 1. Individual; population 6. What are the two conditions required for natural selection to occur? 1. Individuals must vary in characteristics that are heritable 2. In a particular environment, certain versions of the heritable traits help individuals reproduce more than do other versions 7. What was Louis Pasteur s experiment? 1. Pasteur s experiment was meant to support the cell theory and disprove spontaneous generation. To do this, Pasteur boiled the same type of broth in two different flasks to rid of any living organisms. One flask was straight necked, enabling particles or organisms to enter the broth inside. The other flask was swan-necked, disabling particles or organisms to enter the broth inside. 8. How would you correctly write an organisms genus and species? 1. Genus species 9. Describe the relationship between fitness and adaptation. 1. Fitness is the ability of an individual to produce living offspring. Adaptation is a trait that increases the fitness of the individual within an environment. An organism able to produce many surviving offspring has a high fitness and is most evolutionary fit. 10. What do biologist use to compare organisms that all organisms have? 1. rrna 11. How has our understanding of the Tree of Life changed? 1. No longer use the Kindgom, Phylum, Genus, etc. We now have three large domains: Bacteria, Archaea, and Eukarya 2. Fungi are more closely related to animals than plants

4 Chapter 28 Sections VOCABULARY: ancestral trait: A characteristic that existed in an ancestor branches: Represents a population through time character: any genetic, morphological, physiological, or behavioral characteristic to be studied clade: monophyletic group homology: occurs when traits are similar due to shared ancestry cladistics: A method for constructing a phylogenetic tree that is based on identifying the unique traits (shared, derived characters, called synapomorphies) of each monophyletic group homoplasy: Occurs when traits are similar for reasons other than common ancestry (Convergent evolution) derived trait: one that is a modified form of the ancestral trait, found in a descendant; originate via mutation, selection, and genetic drift Hox genes monophyletic group: (clades or lineages) an evolutionary unit that includes an ancestral population and all of its descendants, but no others nodes: (Fork) A point within the tree where a branch splits into two or more branches outgroup: A taxon that diverged prior to the taxa that are the focus of the study; helps to root the tree paraphyletic group: A group that includes an ancestral population and some of its descendants, but not all polytomy: A node that depicts an ancestral branch dividing into three or more (rather than two) descendant branches tip: (Terminal node) Endpoint of a branch; represents a living or extinct group of genes, species, families, phyla or other taxa parsimony: The most likely explanation or pattern is the one that implies the least amount of change root: The most ancestral branch in the tree polyphyletic group: An unnatural group that does not include the most recent common ancestor synapomorphy: A trait found in two or more taxa that is present in their most recent common ancestor, but is missing in more distant ancestors KEY CONCEPTS: 1. Draw a simple phylogenetic tree with one outgroup, 3 nodes, including a node that exhibits polytomy. Label the root, branches, outgroup, nodes.

5 2. How do ancestral traits differ from derived traits? An ancestral trait is a characteristic that existed in an ancestor A derived trait is one that is modified form of the ancestral trait, found in a descendent Originate via mutation, selection, and genetic drift Ancestral and derived traits are relative consider the groups you are studying and questions you are asking Mammals vs Fish Ancestral trait: backbone Derived trait: legs, scales, hair, produce milk, internal fertilization Lizards vs Mammals Ancestral trait: embyotic Derived trait: fur 3. What is convergent evolution and why does it occur? Examples. a. Convergent evolution is when two different taxa have similar characters due to it being best fit for natural selection. Flying squirrel and the sugar glider are not closely related but both have the excess skin. Dolphin and Ichthyosaur are both large marine predators with streamlined bodies and large dorsal fins, but one is a reptile and the other is a mammal and have no close ancestor. 4. What is an outgroup and why is it important to include when evaluating several species and starting the process of drawing a phylogenetic tree? a. An outgroup is a taxon that is closely related to the group being studied, but is not apart of it. b. This allows for biologists to compare groups. They are used to establish the polarity of each trait that is, whether a character state is ancestral or derived 5. What is the relationship between synapomorphies and monophyletic groups? a. Synapomorphies are a trait found it two or more taxa that is present in their most recent common ancestor but is missing in more distant ancestors. It is a shared, derived trait. Synapomorphies allow biologists to recognize monophyletic groups. TOPICS TO DISUSS IF TIME: 6. On a phylogenetic tree, are the taxa at the nodes, roots or tips of the tree? Why is that significant? a. Taxa are at the tips of the tree. This is where the last lineages occur. They are never within a tree. That is, none of the taxa are presumed to be ancestors of others, even if some taxa are extinct. 7. If you have a node with 2 branches, does it matter which branch you write on top and which you write on the bottom? Why is this an important detail to consider as you evaluate phylogenetic trees? a. Nodes are able to rotate. Just because one branch is on the top and closer to a completely different group, doesn t mean that they are more closely related. 8. If a phylogenetic tree lacks a scale bar, can you make inferences about how long ago two species diverged based on the length of each branch? a. No, if the tree does not follow a scale, then you cannot tell the difference. 9. If several taxa are extinct on a phylogenetic tree, does that indicate those taxa are the ancestors of modern taxa?

6 a. Taxa are at the tips of the tree. This is where the last lineages occur. They are never within a tree. That is, none of the taxa are presumed to be ancestors of others, even if some taxa are extinct.