Unit 6 study guide Flashcards
Populations (21 cards)
ecological niche
Is a species way of life or functional role in a community or ecosystem (Its occupation)
example: deer is a herbivore and prey in the forest ecosystem
habitat
the physical location where a species is found ( address)
example: Mule deer can be found in a forest habitat
generalist species
an organism that occupies a broad niche meaning that it can live under a variety of environmental conditions , habitats and/or broad diet.
“Jack of all trades master to none.”
example : rats , deer , coyotes
specialist species
an organism that occupies a narrow niche for habitat , diet and or environment conditions it can tolerate
example: spotted owls, giant pandas
range of tolerance
some animals tolerate a wide range of environmental conditions whereas others can survive only in a narrow range of environmental conditions
- Physical or chemical factors that determine the abundance and distribution of a species
example: chinook salmon - eggs - the optimal temperature range for the survival and development of eggs is 39-54. degrees Fahrenheit warmer temperature leads to mortality.
resource partitioning
other species avoid competition with other species by specializing on a certain of food / food gathering mode
example: hawks , owls feed on a different times of the day . different bird species will feed on different parts of a tree.
native species
A species that naturally occurs in a particular ecosystem . many native species are being decimated due to hunting , habitat destruction ,or displacement by competing with alien species.
immigrant / alien species
species not native to a particular area and have been introduced to that area by humans either by accident or intentionally. many species have been introduced by for human benefit.
Example: game animals have ben introduced for human benefit : hunting , crop species , food .
Example : African honeybees were introduced by accident in South America when a colony escaped.
indicator species
Species that are usually very sensitive to changes in the environment . when the numbers of indicator species declines means something is disrupting the community or ecosystem equilibrium.
keystone species
species whose role in an ecosystem is disproportionately more important or significant compared to biomass or abundance in an ecosystem.
*removal of a keystone species can have a dramatic domino effect and can disrupt the equilibrium of an ecosystem.
foundation species
species that help shape communities by enhancing habitats in ways that help other species. “ Ecosystem Engineers” because their activities enhance/modify the habitat and these modifications benefit other species besides themselves.
trophic cascades
Another concept that is similar to the keystone species and foundation species is a phenomena known as the “trophic cascades”
occurs when the removal of top predator causes a chain of reactions that ripple down the food chain and ultimately disrupts/ destabilizes the ecosystem.
*describes the effect of top predators on the ecosystem vs. keystone and foundation species characterize individual species.
competition
occurs when 2 or more species compete for the same resource : food , water , space , shelter , limiting nutrients, sunlight
* doesn’t mean fighting - one can just be more efficient
competitive exclusion principal
Scientific law / Principal developed by Russian eologist Georgii Frantsevich Gause which states that no two species can stably coexist in an identical niche
predator - prey interactions
prey interactions : one species ( the predator) benefits @the detriment of another (prey). Predators can be carnivores or herbivores.
- predators have evolved a number of strategies to enhance the ability to catch prey
- camoflauge - octopus, leopard
- speed - cheetah
- sit and wait - python
- venom - rattlesnakes
- specialized senses - heat seeking ( pit viper snakes ) echolocation ( bats ) - sonar ( whales )
parasitism
Specialized type of predator-prey interaction where predator is much smaller than its host.
- Parasite benefits @ the cost of the host
- can be external (fleas , ticks , leeches) or internal ( tapeworm , bacteria )
- can play an important ecological role in population control and promoting bio diversity.
mutualism
both organisms benefit from the interaction.
example: flowers and pollinators - nitrogen fixing bacteria and legumes - mycorrihaze fungi on plant roots - clownfish and anemones.
commensalism
relationship where one organism benefits and the other organism is unaffected
carrying capacity
(Symbol K) : Theoretical # of organisms a particular ecosystem can support.
- Equilibrium point when the death rate is equal to birth rate
- populations that are below their carrying capacity have the potential to increase
- populations that are above the carrying capacity require more resources that are available
- Abiotic and biotic factors can limit the carrying capacity of an ecosystem.
r-strategies
Species that have fast population growth rates , high reproductive rates and shorts generations times
- reproduce when conditions are good
- reproduce small offsprings
- offspring dies before reaching reproductive stage
- short life span
- fluctuates wildly above and below carrying capacity
- early reproductive stage
- little or no paternal care
- generalist niche
- early succession species / invasive species.
k-strategies
Have longer generation times , lower reproductive rate.
- produce few large offsprings
- later reproductive stage
- higher offspring survival rate
- longer paternal care involved
- usually longer lifespan
- populations hover around carrying capacity
- large body size
- lower population growth rate
- later successional species , stable environments
- tend to thrive in stable undisturbed habitats
