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Bio 94 Ch. 1
Vocab
Term | Definition |
---|---|
Organism | a life form-- a living entity made up of one or more cells. |
What does it mean to say that something is alive? | Although there is no definition of life that is endorsed by all biologists, most agree that organisms share a suite of five fundamental characteristics. |
Energy | To stay alive and reproduce, organisms have to acquire and use energy. To give just two examples: plants absorb sunlight; animals ingest food. |
Cells | Organisms are made up of membrane-bound units called cells. A cell's membrane regulates the passage of materials between exterior and interior spaces. |
Information | Organisms process hereditary, or genetic, information encoded in units called genes. Organisms also respond to information from the environment and adjust to maintain stable internal conditions. |
Replication | One of the great biologists of the twentieth century, Francois Jacob, said that the dream of a bacterium is to become two bacteria." Almost everything an organism does contributes to one goal: replicating itself. |
Evolution | Organisms are the product of evolution, and their populations continue to evolve. |
Organisms are life forms | because they acquire and use energy, are made up of one or more cells, process information, are capable of replication, are a product of evolution. |
Theory | is an explanation for a very general class of phenomena or observations that are supported by a wide body of evidence. |
Cell theory | this is expressed by fundamental questions: What are organisms made of? Where do they come from. |
The basic conclusion made in the 1800s? | All organisms are made of cells |
Smallest organisms known today? | Bacteria, that are barely 200 nanometers wide, or 200 billionths of a meter. |
Cell | a highly organized compartment that is bounded by a thin, flexible structure called a plasma membrane and that contains concentrated chemicals in an aqueous (watery) solution |
Most scientific theories have two components: | The first describes a pattern in the natural world; the second identifies a mechanism or process that is responsible for creating that pattern. |
Hooke and his fellow scientists did what? | articulated the pattern component of the cell theory. |
Complete Cell Theory | All organisms are made of cells, and all cells come from preexisting cells. |
What does the cell theory maintain? | that cells do not spring to life spontaneously but are produced only when preexisting cells grow and divide. |
Hypothesis | a testable statement to explain a phenomenon or a set of observations |
Prediction | describes a mesurable or observable result that must be correct if a hypothesis is valid. |
Darwin and Wallace important claim concerning patterns that exists in the natural world: | 1. Species are related by common ancestry. 2. Darwin and Wallace proposed that the characteristics of species can be modified from generation to generation. Darwin called this process descent with modification. |
Evolution | A change in the characteristics of a population over time. It means that species are not independent and unchanging entities, but are related to one another and can change through time. |
Natural Selection | Natural selections occurs when two confirmations are met: 1.Individuals within a population vary in characteristics that are heritable- meaning traits can be passed on to offspring. 2. A population is defined as a group of individuals of the same group |
Natural selection vs evolutionary change: | Natural selection acts on individuals while, evolutionary change occurs in populations. |
Artificial selection | changes in populations that occur when humans select certain individuals to produce the most offspring. Beginning in 1896, researchers began long-term selection on maize. |
Fitness | the ability of an individual to produce viable offspring. Individuals with high fitness produce many surviving offspring. |
Adaptation | a trait that increases the fitness of an individual in a particular environment. |
Tree of life | a family tree of organisms. |
Phylogeny | tribe source- their actual genealogical relationships. |
Why might rRNA be useful for understanding the relationships between organisms? | The ribonucleotide sequence in rRNA is a trait that can change during evolution. |
Theory of evolution in organisms | If the theory of evolution is correct, then rRNA sequences should be very similar in closely related organisms but less similar in organisms that are less closely related. ex// plants should share certain changes in rRNA that no other species have. |
The tree of life implied by rRNA that there are three fundamental groups or linkages of organisms: | the bacteria the archaea the eukarya |
Eukaryotic cells | have a membrane bound nucleus. |
Prokaryotic cells | do not have a membrane bound nucleus. |
Taxonomy | the effort to name and classify organisms. |