Final Exam: Fall 23 Flashcards
Competition for a single resource
population dynamics of two competing species can be modeled by extending the logistic growth equation to multiple species
What is N1
the number of species 1
what is N2
the number of species 2
What is intraspecific
1/K or 1/K2
What is interspecific
lil fish thing/K1 or B/K2
Species Richness
often increases from the local to landscape scale because habitat diversity increases along this dimension
alpha (local) diversity
average number of species in a relatively small area of homogenous habitat
gamma (regional) diversity
number of species in all of the habitats that comprise a large geographical region
beta (turnover) diversity
number of species that differ in occurrence between regional and local habitats
regional species pool
collection of species that occurs within a geographical region
How to calculate gamma diversity
Add all of the numbers from the sites and the shared areas
how to calculate alpha diversity
add all from just the main sites (no shared areas) and then divide by the number of main sites
how to calculate beta diversity
gamma diversity - alpha diversity
intraspecific competition
competition among individuals of the same species
interspecific competition
competition among individuals of a different species
what is a resource
anything an organism consumes or uses that causes an increase in population growth rate when it becomes more available.
more resources means more population growth
renewable resources
resources that are regenerated at some rate
nonrenewable resources
resources that are not regenerated at an appreciable rate
liebigs law of the minimum
population sizes are limited by the most limiting resource
what are diatoms
silica for cell walls
suppose you have found that fertilizing grain fields with nitrogen increases crop yield
based on liebigs law of the minimum, how is crop yield most likely to respond as you add more and more nitrogen?
A. yield grows at a faster and faster rate
B. yield grows at a constant rate
C. yield grows but growth slows and eventually stops
C. yield grows but growth slows and eventually stops
competitive exclusion principle
two species cannot coexist indefinitely when they are both limited by the same resource. extinction of population
competition among related species
darwin suggested competition is most intense between related species because they have similar traits and consume similar resources
competition among distant species
competition can also be intense among distantly related species that consume a common resource
given the tremendous diversity in tropical forests and the principle of competitive exclusion, what might explain why so many species coexist there?
A. each species inhabits its own niche and therefore doesn’t share limiting resources
B. Each species depends on the density of at least one other species (mutualism)
C. Competition may not actually drive species to extinction
D. Any of the above
D. Any of the above
abiotic conditions
the ability to compete well may be countered by the ability to persist in harsh abiotic conditions
exploitative competition
competition in which individuals consume and drive down the abundance of a resource so that other individuals survive and reproduce more poorly
interference competition
competitors directly defend resources
apparent competition
two species have a negative effect on each other through an enemy, such as a predator, parasite ,or herbivore
allelopathy
a type of interference competition that occurs when organisms use chemicals to harm their competitors
apex predators eats mesopredators and herbivores, and mesopredators only eat herbivores.
herbivores and meso predators are
1. prey and predator
2. competitors
3. mutualists
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 1, 2, and 3
A. 1 and 2
What is mutualism
mutualism is a positive interaction between two species in which one species receives benefits that only the other species can provide
what is a generalist
species that interact with many other species
what is a specialist
species that interacts with one or a few closely related species
what is an obligate mutualists
species that require each other to persist
what is a facultative mutualist
species where the interaction is not critical to the persistence of either species
what are lichens
fungus + algae/cyanobacteria
mycorrhizal fungi
fungi surround plant roots and help plants get water and minerals
endomycorrhizal fungi
hyphal penetrate root cells between cell walls and the cell membrane
ectomycorrhizal fungi
hyphae surround plant roots and enter between root cells but rarely into the cells
arbuscular mycorrhizal fungi
endomycorrhizal fungi that infect many plants including apple trees, peach trees, coffee trees, and grasses. includes 70-90% of land plant species
mutualistic interactions between plants and bacteria
help plants convert unusable forms of minerals into forms that they can use
suppose that some humans decide to eat all the honeycomb, wax, grubs, etc leaving nothing for the honeyguide. ecologically, the humans and honeyguides are
A. mutualists and mutualists
B. predators and prey
C. parasites and hosts
D. assholes and unlucky
C. parasites and hosts
suppose that apex predators only eat mesopredators and mesopredators only eat herbivores
apex predators and herbivores are
A. prey and predator
B. competitors
C. mutualists
D. none of the above
C. mutualists
negative interactions
when a species in a mutualism provides a benefit to another species, but no longer receives a benefit in return
what is cheating
occurs when one species receives a benefit but does not provide one in return
a cheating mycorrhizal fungus is most unlike
A. a civet that digests coffee beans instead of pooping them out
B. a cancer cell that ignores signals to stop dividing
C. a honey bee that eats nectar but doesn’t transfer pollen
B. a cancer cell that ignores signals to stop dividing
effects on species distributions
the disruption of a mutualism may cause a decline of the species involved and a reduction in their distribution and abundance
communities and mutualism
mutualism can also change the abundance of species through a chain of interactions
the effcts of mutualism on ecosystem function
mutualisms can also have effects at the level of the ecosystem. more nutrients and more productivity
mutualism and convervation
loss of disperses can result in a reduction in plant abundance
zonation meaning
distribution of species into different zones. there are unique or different communities at each zone
ecotone
boundary created by sharp changes in environmentally conditions over a relatively short distance, accompanied by a major change in the composition.
`interdependent communities
communities in which species abundances are positively linked
independent communities
communities in which species abundances are not positively linked
interdependence
removing a species should cause other species to decline in abundance
independence
removing a species should cause negligible or positive changes in abundance of other species
assuming a model of species independence, which ecological relationships are not possible
1. competition
2. predation
3. mutualism
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 1, 2, and 3
C. 2 and 3
species richness meaning
number of species in a community
relative abundance
proportion of individuals in a community represented by each species