Fall Semester Test Flashcards
What is the definition of science according to the National Academy of Science?
The use of evidence to construct testable explanations and predictions of natural phenomena and the knowledge generated through this process.
What is beyond the limits and scope of scientific study?
Science doesn’t make moral or aesthetic judgments and doesn’t tell you how to use scientific knowledge. It also doesn’t draw conclusions about supernatural explanations.
What IS a hypothesis?
A hypothesis IS a proposed testable explanation for a narrow set of phenomena, usually based on prior scientific background knowledge, preliminary observations, and logic.
What IS NOT a hypothesis/the common misconceptions about a hypothesis?
It IS NOT predictions, an educated guess, does not tell you how to use scientific knowledge, and does not draw conclusions about supernatural explanations.
What is a theory in science?
A theory is an explanation of scientific phenomena that has already been tested and supported by data time and time again. If something is called a theory in science, that means there has never been evidence that has refuted the theory. However, scientific theories may be revised or modified in the face of new, substantial evidence.
How are a hypothesis and a theory similar and different?
They are both not guesses, and answer the questions “why” and “how”. They are unalike because theories are more broad, and strongly supported by many lines of previous evidence.
What are the roots in the word “biology” and their meanings?
bio = life & logy = study (The study of life)
Compare and contrast random and systematic errors.
Random errors caused by unknown and unpredictable changes in the experiment + statistical analysis of data help take them into account. Systematic errors caused by instruments used to measure, like a miscalculated scale or by a human bias + the affect the ability to draw valid conclusions! Random errors affect accuracy, and systematic errors affect precision. (think the target example)
Design Bias?
introduced when the reaserchers design itself is flawed, the expiriment itself has a bias.
Selection Bias?
occurs when the process of sampling actually introduces an inherent bias into the study
Procedural Bias?
an unfair amount of pressure is applied to the subjects being studied
Reporting Bias?
a scientist’s beliefs influence their conclusions
Measurement Bias?
Systematic errors that favors a certain measurement over another
Explain what makes science trustworthy.
peer review makes science trustworthy because our research can sometimes have errors, so when others help us and review our studies, we can get a more accurate conclusion.
What are the seven characteristics of life that help us determine what is living and nonliving?
-Orderly Structure (cell or cells)
-Growth and Development
-Reproduction (passing trait to offspring asexually or sexually)
-Metabolism (energy processing)
-Homeostasis (regulation of internal states)
-Response to environment (external stimulus)
-Evolutionary adaption (by populations, not individuals)
What are the three main reasons viruses are not living?
Viruses are not made out of cells (orderly structure), Cannot keep themselves in a stable state (homeostasis), and do not make their own energy (metabolism). They cannot reproduce or grow and develop on their own.
Using scientific prefixes and suffixes (roots), define the words “prokaryote” and “eukaryote.”
Pro = before & Eu = true
kary = kernel (representing the cell nucleus)
ote = (symbolizes a noun for an individual)
Prokaryote means an organism was around before the cell nucleus evolved, and Eukaryote means an organism that has a true cell nucleus.
What are the structures (e.g., organelles present and lacking) and functions for prokaryotic cells?
Prokaryotes have free floating DNA, Cytoplasm, Ribosomes, Cell Membranes and Cell Walls. Some even have flagellum. The main point is that prokaryotic cells DO NOT have a nucleus.
What are the 3 domains (and kingdoms) of life in modern taxonomy?
Archaea, Eubactiera, and Eukarya (Fungi, Protista, Plante, and Anamalia)
What are archaea?
Single celled prokaryotes that reproduce asexually made of proteins that live in extreme environments. Most of them are obligate anaerobes, but some vary.
What are Eubacteria?
Single celled prokaryotes that reproduce asexually made of peptidoglycan (important for gram stain). They can live almost anywhere, and most of obligate aerobes or faculatative aerobes.
What are Eukarya?
Single and Multicellular eukaryotes that can reproduce asexually or sexually made of various proteins. They contain a nucleus and membrane bound organelles.
Why did people originally think that archaea and bacteria were in the same group?
Because they both have no true species. They transfer genes among themselves outside of typical reproduction. Their structures are also very physically similar, making it difficult to classify them into the correct group.
The 3 most common shapes for bacteria are?
Bacillus (rod-shaped), Coccus (ball-shaped), and Spirillum (spiral-shaped)
Anamalia are?
multicellular organisms that have no cell walls, and are heterotrophs (need to search to find food)
Plantae are?
multicellular organisms that have protective cell walls, and are autotrophs (make their own food)
Fungi are?
multicellular or unicellular organisms that have tough chitin walls that are hetotrophic (decomposers)
Protista are?
unicellular organisms that are autotrophic or hetotrophic
What is an infectious agent?
agents that cause disease that are caused by pathogens (or germs)
What are the 6 modes of disease transmission & examples of each?
food/waterborne, airborne, vector, sexual, contact, and bloodborne
What are some strategies for prevention & control of pathogen spread (transmission)?
preventing the contamination of food and water supplies, hand washing & good hygiene, avoiding contact with body fluids, and controlling insect populations.
Describe where antibiotic resistance came from and how its caused?
Antibiotic resistance already exists in nature, but it’s grown by the overuse of antibiotics by people. (Think of Addie’s case for an example)
What does the growth curve look like for bacteria?
The growth curve starts off small, and gains popularity very quickly due to their reproduction style. On a graph, it would be a line going from almost horizontal to almost vertical very quickly.
How does carrying capacity regulate population growth?
When a population is small, the organisms can thrive and reproduce quickly, and as their numbers increase the resources get much more scarce. This is when the population reaches around its carrying capacity.
What are variations in traits?
Genetic variation is the gene pool for a species, Physical trait variation is differences in an organisms physical structure that can give it environmental advantages. Variation can also come from sexual recombination.
Do individuals or populations adapt to an envionrmnet?
Only populations can adapt and evolve because natural selection will favor a positive trait, slowly eliminating the unfavorable ones so the organism evolves to better fit their environment.
What is natural selection and how does it work?
Def - the process by which organisms with favorable traits/variations survive and produce more offspring than less well-adapted individuals. This basically means that the favorable traits increase in the gene pool, as the environment naturally selects the best traits to have a high fitness.
What are the four mechanisms of natural selection and what do they do?
Variation - genetic differences in a population that are heritable to the next generation. They are always hereitably acquired.
Overproduction - Producing too many offspring in a population for the given environment, resulting in competition between resources.
Adaption - inherited trait that allows individuals to survive and reproduce better than others who don’t have the trait.
Descent with modification - organisms with adaptions over time produce more organisms with that adaption. The modification to the population will continue as long as the environment still pressures the individuals for this trait.
What types of sexual selection exist and how do they play a role in natural selection?
Sexual selection is when the individuals in a population apply the selective pressure based on their preferences. Intersexual selection is “Choosiness” and Intrasexual selection is “Competition”.
Differentiate between direction selection, stabilizing selection, and diversifying selection. Which one describes the microeveolution of the bacteria in Addie’s body?
Directional selection favors one extreme, stabilizing selection favors the intermediate phenotype, reducing variation, and diversifying selection favors both extremes, increasing variation. Addie’s infection was directional selection because her body favored the extreme (antibiotic resistant bacteria).
Explain gene flow and give a specific example.
Gene flow def - the movement of genes in or out of a population due to interbreeding (Gene the purple giraffe in our videos) The less flow in populations, the more genetically different the populations grow.
Explain genetic drift and give a specific example.
Def - the random change in allele frequency in a population (The meteorite in our giraffe video) The population evolves due to random chance, but not because it is pressured by the environment.
What is the bottleneck effect?
A form of genetic drift that results from an event that drastically reduces the size of a population.
What is the founders effect?
A form of genetic drift that occurs after a small population colonizes a new area (Think Juncos)
What do we mean when we say it’s not survival of the fittest, it’s survival of the “fit enough”?
We mean that the individuals with the most fitness are determined via their own population, so even if there once was a more fit individual, at the moment the best option (although worse) is fit enough.
What are three things that can keep natural selection from producing a “perfectly engineered” trait?
- Lack of necessary genetic variation (selection can only operate on existing traits, no matter how useful one could be).
- Constraints due to natural history (the basic structure is laid out for an organisms structure. They cant just grow wings or change their skin as those things cannot be altered)
- Trade-offs (Organisms could have some new structures, but they may have to sacrifice something else for that. For example, we could have camouflage skin but that causes us to be allergic to the sun, meaning we would die earlier)
What is a cladogram and how is it used? How is it similar and different from a phylogenetic tree?
Cladograms are based on differences in phenotypic traits of the group depicted (not genetics). Cladograms show a series of ancestors, where we can then compare their least common ancestors and their traits to identify similarities. They are different from phylogenetic trees because phylogenetic trees only represent genetic relationships and lineages, while cladograms are based on differences in traits.
Describe how the Miller-Urey experiment and the meteorite hypothesis explain how organic molecules might have formed in early Earth.
Miller-Urey demonstrated that organic compounds could be MADE on earth, and the meteorite demonstrated that organic compounds could have ARRIVED on earth.
How do the lipid-membrane hypothesis and the iron-sulfide hypothesis explain how membranes formed around early organic molecules?
Iron-sulfide demonstrated that membranes formed on the ocean floor, becoming the “first cell membranes”, and the lipid-membrane demonstrated lipid molecules randomly forming liposomes, which gave rise to the “first cells”.
Describe the endo-symbiotic theory and how fits into explanations for early life on Earth.
Early mitochondria and chloroplasts were once simple prokaryotic cells that were taken in by larger prokaryotes, and instead of being eaten they stayed inside the prokaryotic cell to give it sugars, and the larger prokaryotic cell gave the mitochondria or chloroplast protection. Proves how eukaryotic cells most likely came to be.
Explain how there is evidence for evolution in the fossil record.
Paleontology provides information about evolution by studying old fossils deep underground, and seeing their evolution and structures compared to modern day species.
Explain how there is evidence for evolution in homologies. (Anatomical homologous structures, Vestigial structures, Molecular homologies, and Developmental homologous structures)
Anatomical homologous structures - Represents similar features in different organisms, showing that evolution has divided those organisms to look more and more different, yet the still kept some of their original traits.
Vestigial structures - suggests that evolution has caused organisms to slowly get rid of the extra structure or traits they do not need anymore. The ancestors may have used them, but the common day organisms do not.
Molecular homologies - shows similarity in DNA and cellular structure. Pseudogenes prove common ancestry because they no longer function, but look like regular genes. They’re just like a vestigial structure.
Developmental homologous structures - similarities in the embryos shown representing common ancestry
In what way do analogous structures not provide evidence for evolution?
Analogous structures prove that just because two organisms have a similar function does not mean they are related in any way, it just means that they may need to have similar functions to thrive.
HOX genes (homo-box genes)
They provide evidence of a very distant common ancestor. They relate to molecular homologies because they are genes, and developmental because they are dealing with embryonic development.
How do we define species?
a group of organisms that are closely related and can mate to reproduce fertile offspring
Explain three mechanisms by which a population might become reproductively isolated from other populations of the same species
Behavioral isolation - isolation between populations due to differences in courtship or mating behaviors. This can include chemical scents, courtship dances of birds, songs of frogs, etc.
Geographic isolation - isolation between populations due to physical barriers, like the formation of the Isthmus of Panama between North and South America.
Temporal isolation - isolation between populations due to barriers related to time, such as differences in mating periods or differences in the time of day that individuals are most active, etc. The book gives examples of pine trees that shed pollen during different seasons.
Punctuated equilibrium
Theory that drastic changes create new species that then change very little over time
Adaptive radiation
The process by which one species evolves and gives rise to many descendant species that occupy different ecological niches
Divergent evolution
When two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental and social pressures
Convergent evolution
The process whereby distantly related organisms independently evolve similar traits to adapt to similar necessities.
Coevolution
The process of reciprocal evolutionary change that occurs between pairs of species or among groups of species as they interact with one another (the plant evolving with the ants example)(results in strong competition)
What is the difference between background extinction and mass extinction?
Background extinction happens at a low and slow rate, and it’s caused by local changes to the environment, affecting few species in a small area. Mass extinction are rare and intense extinctions that wipe out species at a global level (catastrophic events).
What is the evidence for evolution in the UCSD population? Include in your explanation a description of the scientists’ techniques. What kind of data did they collect as evidence?
The evidence for evolution in the Juncos is that they are no longer interbreeding, as only the UCSD birds have the allele 208. This proves that they are driving towards evolution, and becoming two different species. We are seeing the impact of geographic and temporal (only from the light) isolation. The scientists tested UCSD and Mt Laguna birds and compared things like testosterone, flight initiation distance, and the common garden experiment.
Marcus Vitruvius Pollio (c. 80-15 BCE)
Proposed the idea that the human figure was beautiful because of its symmetry, and our height is the same as our arm span.
Carolus Linnaeus (1700s)
Classification system for binomial nomenclature. Classifies organisms based of their physical characteristics.
John Snow (1854)
Discovered the cause of the Cholera outbreak (it traveled through water!). Also known as the “father of epidemiology”
Charles Lyell (1800s)
Expanded on Hutton’s theory of gradualism into the theory of utilitarianism
Charles Darwin
The “Father of evolution” who discovered the mechanics of evolution. His voyage included him witnessing the Chilean earthquake, which uprooted rock and showed fossil records.
Compare and contrast the ideas of Jean Baptiste Lamarck and Charles Darwin
Lamarck believed that if an organism changes in its lifetime to better fit its environment, that change is passed to its offspring. He said change is motivated by what organisms need or want, and things we dont need will eventually go away. Darwin believed that the desires of animals have nothing to do with how they evolve and adapt, and the genetically benefited animals will give their good genes to their offspring.
