Biology Chapter 1: Biology and the Tree of Liife
Terms
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- Theory
- an explanation for a very general class of phenomenon or observations
- What question do cell theory and the theory of evolution by natural selection answer?
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1. How are organisms structured,
and
2. Where did they come from? - Describe Hooke's experiment and discovery.
- Using a 30X microscope, Hooke examined cork and discovered small, pore-like compartments (cells)
- Describe van Leeuwwenhoek's experiment and discovery.
- Using a more powerful microscope, van Leeuwwenhoek studied pond water and first observes the single celled organism; Also observes structure of human blood & sperm
- Cell
- A highly organized compartment bound by a plasma membrane and containing concentrated chemicals in an aqueous solution
- Name the 2 components of theories.
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1. Describes a pattern in the natural world, and
2. Identifies the reason (mechanism or process) behind that pattern - Describe Rudolph Virchow's contribution to cell theory.
- Virchow found that all cells arise from pre-existing cells
- Describe the complete cell theory.
- All organisms are made of cells and all cells come from pre-existing cells
- Spontaneous Generation
- Organisms arise under certain conditions
- Hypothesis
- Proposed explanation
- What was the purpose of Louis Pasteur's experiment?
- Pasteur wanted to test the validity of the new "all-cells-from-cells" theory against the popularly accepted spontaneous generation
- Describe the experiment Pasteur used.
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1. Place broth in stright and swan flasks
2. Boil to kill living cells
3. Pre-exisiting cells enter from air; enter stright, are trapped in the swan's neck - What were the results and conclusions of Pasteur's experiment?
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*Straight neck: Cells appear in the broth
*Swan neck: Broth remains sterile
*Conclusion: "all-cells-from-cells"
supported - What was the experimental factor in the Pasteur experiment?
- The exposure to pre-exsting cells
- What was Darwin and Wallace's hypothesis?
- species come from other, pre-existing species, and species change though time
- Name the 2 claims made in Darwin/Wallace's theory.
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1. Species share a common ancestry
and
2. Characteristics of species can and will modify over genreations (heredity) - How does evolution occur?
- Evolution occurs via natural selection
- What are the 2 conditions that must be met for natural selection to occur?
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1. Individuals in a population vary in characteristics that are hereditary
2. In any environment, certain heritable characteristics aid survival, reproduction - Population
- A group of individuals of the ame species that live in the same area at hte same time
- Describe the wheat experiment from Darwin/Wallace.
- Short parents usu. have short offspring. In windy environments, tall wheat is blown down. Shorter wheat survives. Generations get shorter & shorter
- T/F Natural Selection works direstly on a population.
- False. Natural selection works on a population via individuals, allowing those most suited to survive to reproduce and inc. the frequency of those traits
- Fitness
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The ability of the individual to survive and reproduce;
Measured in number of offspring produced - Adaptation
- A trait that increases the fitness of an indiviaual in a oarticular environment
- Describe how broccoli came into existance.
- Individuals of the mustard family with large and compact stalks were mated together. Over time and genreations, stalks became very large and compact
- Why does natural selection occur?
- Natural Selection occurs because individuals with certain traits are able to leave more offspring than those without these heritable traits
- What are the 2 central ideas of Biology?
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1. The cell is the fundamental structural unit in all organisms; and
2. All species are related by a common ancestry and changed over time via n.s. - Speciation
- The divergence of new species caused by natural selection
- What are the two possible changes from antural selection?
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1. Change within species (ie evolution)
and
2. Change between species (ie speciation) - Taxonomy
- The effort to name and classify organsims
- Describe the system of Linnaeus taxonomy.
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1. The first part indicates the genus of the orgaansim
2. The second part indicates the species of the organism - Species
- Individuals that regularly breed together and have chasracteristics that are distinct from those of other species
- Bionomial Nomenclature
- the 2 part naming system of Linnaeus Taxonomy
- Name the main Taxonomy groups.
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Kingdom, Phyllum, Class, Order, Family, Genus, Species
(least to most specific) - How many Kingdoms did Linnaeus suggest?
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Two : plants and animals
Plants- Organisms don't move & make own food
Animals- Move and eat other organisms - What was the problem with Linnaeus' division of Kingdoms?
- Not all organisms fit in one category or the other; ie bacteria move and make thier own food
- How did the goal of Taxonomy change?
- Rather than link organisms by appearance or road characteristics, the goal became linking the genealogical relationships; create a phylogeny
- Phylogeny
- The true historical relationship among the types of organisms
- Eukaryotes
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Organisms containign a nucleus;
Usually multicellular - Prokaryotes
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Organisms without a nucleus;
Usually unicellular - Expalin how Woese 's Kingdom theory differed from the 2 or 5 Kingdom theories.
- Woese looked at the chemical components (rRna) of organisms rather than the physical attributes (ability to move, presence of nucleus)
- How did Woese examine the theory of evolution in organisms (what premise) ?
- Woese guessed that the rRna of species closely related would be more similar than those less closey related. Time since species divergence = more change
- Name the 5 Kingdoms in the 5 Kingdom system.
- Kingdom Monera (all prokaryotes), Kingdom Protista (unicellular eukaryotes), Kingdom Plantae, Kingdom Fingi, and Kingdom Animalia
- Did Linnaeus and Woese have the same goal in their classifications?
- No. Linnaeus created Kingdoms based on physical attribute to organize. Woese wanted to determine the phylogeny of the organisms.
- Phylogenic Tree
- A diagram that depicts the evolutionary history of organisms based on Woese's model
- How are close relaitons shown on a Phylogenic Tree?
- Organisms located on close branches are shown to have close relations
- What are the 3 main groups on the Tree of Life?
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1. The bacteria
2. Another group of prokaryotes; single celled organisms called "the Archae"
3. The eukryotes - Name the additional taxonomy level created by Woese.
- The domain
- Are fungi more closely related to plants or animals according to Woese?
- Animals
- What are is the 2 step process of hypothesis testing?
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1. State the hypothesis as accurately as possible and list the predictions
2. Design an observaitobal study or experiment to test these predictions - How can you tell if a hypothesis is supported?
- If the predictions are accurate, the hypothesis is supported. If they are inaccurate, continue testing, modify the hypothesis, or consider other reasons
- Prediction
- Something that can be measured and mus tbe correct in order for the hypothesis to be true
- What are the predictions of the food competition hypothesis of giraffes?
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1. Neck length is variable among giraffes
2. Neck length in giraffes is a heritable trait
3. giraffes feed high in trees in drought - What is the argument against the food competition theory of giraffes?
- Giraffes usually feed at about 60% of their full height
- What is the alternate hypothesis for long necks in giraffes?
- The longer neck length allows for harder hits during mating season; Thus those that have longer necks have won more often and reproduced more long necks
- What is the directed dispersal hypothesis?
- Natural selection should favor the seeds that discourage the "seed predation" from occurring but allow for "seed dispersal"
- Describe the experiment preformed to test the direct dispersal hypothesis.
- Mice, seed predaors, and thrashers, seed dispersers, were presented with hackberries, and both pungent and non-pungent chilies & percent eaten recorded
- Null Hypothesis
- The results of an experiment if the hypothsis being tested is wrong; Often, it states that there is no difference between groups
- What were the results of the Chili Pepper experiment ( directed dispersal ) ?
- Both mice and thrashers ate a comparable amount of Hackberries. Mice ate no pungent chilies and few non-pungent. Thrashers ate both chilies
- What was the experimental variable in the directed dispersal experiment?
- The amount of berries/chilies eaten in the set tme frame was the experimental variable
- What are the three key points for experimentation illustrated by the directed dispersal experiment?
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1. Include control groups (the hackberries)
2. Control experimental conditions
3. Repeat the experiment - Describe the follow up experiment to the directed dispersal experiment.
- Non-pungent chilies were eateb by both predators. They were then collected and planted, allong with uneaten seeds. The seeds that germinated were counted
- What were the results of the second directed dispersal experiment?
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Seeds eaten by the mice were destroyed.
Seeds eaten by the thrashers were effectively dispesed. Therefore, the capsaicin level = adaptation vs. mice - What aspect of cellular theory is van Leeuwenhoek known for?
- van Leeuwenhoek is knoen for introducing the idea of cellular diversity