Chapter 4 Flashcards
What is Competitive Exclusion?
The principle of competitive exclusion which states that no two species can occupy the same ecological niche at the same time. The one that is more efficient at using resources will exclude the other.
Define:
- Adaptation
- Natural Selection
- Mutation
- Evolution
- Adaptation: is the acquisition of traits that allow a species to survive in its environment. Adaptation is explained by Charles Darwin’s theory of evolution by natural selection
- Natural Selection: is the process of better-selected individuals passing their traits to the next generation is called natural selection
- Mutation: is changes in DNA coding sequence that occur by chance (e.g., random mistakes in DNA replication, exposure to radiation, toxins…)
- Evolution: A trait must be inherited (genetic) for it to evolve. Individuals with traits that make them suited to a particular environment survive and reproduce at a greater rate in that environment than individuals with less suitable traits.
What are:
- Critical Factors
- Tolerance Limits
- Zone of Intolerance
- Physiological Stress
- Critical Factors: The single factor in shortest supply relative to demand is the Critical Factor
determining where a species lives. The factor closest to the tolerance limits is the critical factor
that determines where an organism can live. - Tolerance Limits: Each environmental factor has both minimum and maximum levels, or
tolerance limits, beyond which a particular species cannot survive or is unable to reproduce. - Zone of Intolerance: is when species are absent in that environment due to the inability to thrive
- Physiological Stress: Environmental factors that affect an organisms ability to thrive due to
inappropriate levels of moisture, temperature, pH, light, nutrients, etc..
What is the difference between Ecological Niche and Habitat?
- Ecological Niche: is describes either the role played by a species in a biological community or
the total set of environmental factors that determine a species distribution - Habitat: Is the place or set of environmental conditions in which a particular organism lives
In terms of survival, which has a greater chance of survival, a generalist or a specialist? Why?
Generalists because they can thrive in a broad variety of environments.
Two species coexisting in the same habitat is called?
A) Competitive Exclusion
B) Resource Partitioning
B) Resource Partitioning
What is:
- Allopatric Speciation
- Sympatric Speciation
- Allopatric Speciation: is the development of a new species. This can occur due to geographic
isolation whereby a sub-population becomes separated from the main population and can no
longer share genes with it. The new population evolves independently of the first, creating a new
species. - Sympatric Speciation: is when organisms continue to live in the same place but become isolated
by some other means. Example: Some fern species have doubled the number of chromosomes
they have. This prevents them from breeding with the population from which they originally
came and effectively creates a new species.
Define:
- Directional Selection
- Disruptive Selection
- Stabilizing Selection
- Directional Selection: is the the shift toward one extreme of a trait
- Disruptive Selection: is when traits diverge toward the two extremes
- Stabilizing Selection: is when a range of a traits is narrowed
Define Taxonomy
Taxonomy is the study of organisms and their relationships. It traces how organisms have descended from common ancestors.
Scientists assign every species a Latin name with two parts (a binomial) so that everyone can recognize a particular organism accurately. For example, Pinus resinosa can commonly be referred to as the red pine, Norway pine, or just as a pine. Organisms are then categorized into broader taxonomic categories such as kingdoms, phyla, families, genera,
etc.
What’s the difference between intra-specific and inter-specific competition?
Intra-Specific Competition: is competition among members of the same species which can be reduced if: young disperse, exhibiting strong territoriality, resource partitioning between
generations
Inter-Specific Competition: is competition between members of different species
What is Predator-Mediated Competition?
Predator-Mediated Competition: is when one species may be the best competitor in a given
location, but predators may reduce its abundance and allow the weaker competitor to increase
its numbers
What is it called when Two harmful organisms evolve to look alike in order to avoid predators?
Mullerian Mimicry
What are the 3 forms of Symbiosis?
- Mutualism: is when both organisms benefit from their association
- Commensalism: is when one species benefits while the other neither benefits nor is harmed
- Parasitism: is a form of predation, is also sometimes considered a symbiosis because of the
dependency of the parasite on its host.
What is the importance of Keystone Species?
A keystone species plays a critical role in a biological community that is out of proportion to its
abundance. For example, in the tropics, figs bear fruit year around. In the dry season, this is the
only food available for many species. If figs were removed from the forest, many fruit-eating
animals would disappear; and this in turn would affect many other plants that depend upon
these frugivores for pollination. So, the fig is key to the survival of the community.
Define Primary Productivity and Net-Primary Productivity
Primary Productivity: Rate of biomass production. Used as an indication of the rate of solar
energy conversion to chemical energy
Net Primary Productivity: is energy left after respiration tropical forests, coral reefs, and
estuaries have some of the highest levels of productivity.
