Unifying Themes & Biological Hierarchy Flashcards
What is scientific theory?
an explanation of some aspect of life based on facts, experimentation, and evidence
What are the 2 elements of scientific theory?
- Pattern
- Process
What is cell theory?
- All organisms are made of cells
- All cells came from pre-existing cells
What does the cell theory tell us about life?
Life is continuous: The cells of an organism came from a single fertilized egg, which came from the parent’s gametes’, etc.
What is evolutionary theory?
- Evolution explains variation, how that variation occurred and what can happen if environmental conditions change.
- All species are related through common ancestry.
What is the connection between cell theory and evolutionary theory?
Cell theory states that all cells come from pre-existing cells, thus all organisms must be descended from a common ancestor.
What is evolution?
The heritable/genetic change in a population over time
What is the mechanism for evolution?
Natural selection rules evolutionary change.
What is the biological hierarchy?
- The organization of life
- atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, biosphere.
What are the 3 important elements of the biological hierarchy?
- There is similarity between individuals within each level of the hierarchy.
- The units of one level of the hierarchy define the next.
- Emergent properties
What is an emergent property?
A collection of units at 1 level take on a trait that is greater than the sum of the parts
Explain how reproduction is an emergent property of both the organismal and population levels.
- Organ systems, themselves, cannot reproduce but an organism has the ability to. Asexually reproductive organisms are able to use their organ systems to reproduce. It’s the units of one level (organ systems) gathering to take on a trait/action greater than themselves.
- Many sexually reproductive species require two organisms for reproduction. Thus, a (small) population of species is required for reproduction. It is the collection of multiple units (multiple organisms) in a level to take on a trait/action that is greater than the sum of the parts.
What are communities?
Collections of populations of different species living together in one area. Boundaries of this area may be set up by natural structure (e.g. shorelines) or arbitrarily determined by us.
What are ecosystems?
Ecosystems are communities plus abiotic factors.
What is the biosphere?
The collection of all the ecosystems.
What is the relationship between natural selection, evolution, individuals, and populations?
Natural selection acts on individuals. Those selected individuals are part of a population that evolves as a result of natural selection.
What is the importance of the term “nested hierarchy”?
Changes at each level affect the next level. If a change occurs at the organismal level, then it will affect the population level, then the community level, and then the ecosystem level.
What is biological fitness?
The amount of offspring you can produce, or the amount of genes you can get into the next generation
What is social vigilance?
An emergent property of the population level, that allows populations to watch out for each other.
How does energy flow fit into the biological hierarchy?
Energy flow fits into the ecosystem level because energy flows through both abiotic and biotic factors.
What is a biome?
A collection of similar ecosystems.
Why aren’t biomes a part of the biological hierarchy?
Biomes don’t have any emergent properties.
