Ecology test #3 . clap this up

Overgrowth

When one species grows bigger than another and takes its space (mostly in plants) If two plants are trying to live in the same area and one plant starts to grow so big that it blocks the sun and water from the other plant, so it dies.

Definitive host

a host in which the parasite reaches maturity and, if possible, reproduces sexually

Predator/Prey interactions

**()()**

Competitive release (niche expansion)

Niche expansion in response to reduced interspecific competition. occurs when one of two species competing for the same resource disappears, thereby allowing the remaining competitor to utilize the resource more fully than it could in the presence of the first species

Benefits of cooperation

More efficient protection (vigilance) - more time to eat -Can handle prey otherwise impossible

Growth rate of pred pop = 0

When Nh = dp/fc Nh= prey population f = conversion of prey into pred offspring c = capture efficiency dp= predator deaths

Growth rate of pred population increases

When Nh > dp/fc

Growth rate of prey pop declines

When Np > rh/c

Chase down

Must be fast Or have good endurance (at least better than your prey) (Assumes that you can handle prey on your own)

Types of biotic interactions

Mutualism (cooperation) Predation (Parasitism) Competition Commensalism Ammensalism

Specialist

Narrow niche, use a specific range of resources Under stable conditions More specialists in the tropics panda koala aye-aye

Amensalism

Negative for individual A, individual B is unaffected -0 Stepping on a bug

Competition

Neither is doing as well as if they didn't have to compete but they don't have a choice Interspecific- members of different species compete for a shared resource. Intraspecific- members of the same species compete for limited resources. --

Liebig's law of the minimum

"The availability of the most abundant nutrient in the soil is only as good as the availability of the least abundant nutrient in the soil." Or, to put it more plainly, "A chain is only as strong as its weakest link."

Kleptoparasitism

- Form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food.

Mechanical defenses

-Sharp quills of a porcupine, prickly spines of a cactus, tough armor on an armadillo

Predator strategies

...

Parasite classifications

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Chemical (allelopathy)

A biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial (positive allelopathy) or detrimental (negative allelopathy) effects on the target organisms

Camouflage

A form of mimicry The hiding of something as a result of its appearance cryptic coloration

Mutualism

A relationship between two species in which both species benefit -Interactions are positive for both participants -Relationship may depend upon environmental conditions -Again may be facultative or obligate, symbiotic or not -Trophic, habitat, service (defensive, dispersive) -Penalties to prevent cheating example: Mycorrhizae and plants Increase access to nutrients Increase access to water

Constitutive response

A response that is always present (thorns)

Similarities

Both : one player benefits other is harmed Both: effect population of exploited species

Aposmatic coloration

Bright colors to show that one is poisonous

Effects of parasitism

Can change outcome of competition Can "regulate" populations of host species Can affect mate choice Feather colors Can lead to co-evolution Eventually perhaps to mutualistic relationship Or vice versa?

Cooperation

Common in carnivores Can overwhelm otherwise unmanageable prey Pack hunters (wolves, lions etc) Social foragers (gulls, primates etc) White pelicans Bubblenetting (whales)

Grazers

Consume only part of each prey item - usually don't kill it Consume several or many in lifetime

Parasites

Consume only part of host item - usually don't kill it outright Attack relatively few hosts in lifetime

Exploitative competition

Deprive others of resources Exploitation competition occurs indirectly through a common limiting resource which acts as an intermediate. For example, use of resources depletes the amount available to others, or they compete for space. Also known as exploitative competition.

The lotka volterra model ...

Describes the cycling of predator and prey populations in relation to each other Other, more complex models actually better describe cycling of predator and prey populations but all generally show that predator-prey interactions have the potential to cause population _cycles__

Competitive outcomes altered by

Disturbance Interactions with other species Evolution (resource partitioning) Character displacement

Competitive exclusion principle

Ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time Gause's law - is a proposition that states that two species competing for the same resource cannot coexist at constant population values, if other ecological factors remain constant. When one species has even the slightest advantage or edge over another then the one with the advantage will dominate in the long term

Ecto

External parasite- lamprey

Hemi

Facultative parasite - an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle. -Examples of facultative parasitism occur among many species of fungi, such as family members of the genus Armillaria.

Arrangement of isoclines

Generates graphs w/ 4 possible arrangements of _isoclines_ (lines where there is no increase or decrease in population size)

Permanent obligatory interspecific

Has to do it to survive, done to another species, permanent

Down sides of cooperation

Have to share Increased conspiciousness (more visible) Have to obtain more food

Growth rate of predator population decreases when

If Nh < dp/fc

Unstable equilibrium (competition can go either way

In the third scenario, the isoclines of the two species cross one another. Here, the carrying capacity of species 1 (K1) is higher than the carrying capacity of species 2 divided by the competition coefficient (K2/a21), and the carrying capacity of species 2 (K2) is higher than the carrying capacity of species 1 divided by the competition coefficient (K1/a12). - Below both isoclines and above both isoclines the populations increase or decrease as in the first two scenarios, and there is an unstable equilibrium point (closed circle) where the isoclines intersect. -For points above the dashed pink line (species 2 isocline) and below the solid yellow line (species 1 isocline), the outcome is the same as in the first scenario: competitive exclusion of species 2 by species 1. -On the other hand, for points above the solid yellow line (species 1 isocline) and below the dashed pink line (species 2 isocline), the outcome is the same as in the second scenario: competitive exclusion of species 1 by species 2. The two stable equilibrium points are again represented by open circles. In this scenario, the outcome depends on the initial abundances of the two species.

Lotka/Volterra model of competition

Include a coefficient of competition (a) representing the effect of species 2 on species 1 - multiplying N2 by a makes it the equivalent of individuals in species 1 a simple model of the population dynamics of species competing for some common resource. They can be further generalized to include trophic interactions.

Predation

Individual A benefits while individual B does not benefit at all since they are being preyed upon Hawk / mouse, etc Cowbird, lamprey +-

Commensalism

Individual A gets a benefit and individual B is unaffected +0 butterfly sipping sugar off turtles nose

Mechanisms of competition

Interference - directly affect other orgs Chemical - allelopathy Territorial Encounter Overgrowth

Endo

Internal parasite- roundworm, tapeworm

Interspecific parasitism

Interspecific parasitism (host-parasite interactions, e.g. ectoparasites, endoparasites, viruses, pathogens)

Intraspecific parasitism

Intraspecific parasitism (within-species brood parasitism, e.g. egg dumping, sneaking)

Factors which cause cycles?

Lots of things alter cycles Habitat complexity, other species, genetics, hormones, even evolution Bottom line is: we don't really know

Vector

Many parasites have more than one host Transmission from one host to another may require ____

Competition restricts ______

Niches

Holo

Obligate parasite -a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. If an obligate parasite cannot obtain a host it will fail to reproduce.

Temporary obligatory interspecific

Only parasitizes during the nesting season. Example would be brown headed cowbird Only done in times where needed, done to other species, temporarily -Brown-headed cowbird_(Molothrus ater) -Specialized behaviors of young

Consumptive competition

Organisms consume the same resource occurs when food is a limited resource and individuals reduce one another's intake

Distribution is affected by more than just competition

Other relationships - predation, social interactions... Physiology Genetics Environmental tolerances

Contest competition

Refers to a situation where available resources, such as food and mates, are utilized only by one or a few individuals, thus preventing development or reproduction of other individuals.

Mutualism (cooperation)

Positive interaction for both animals each individual benefits from the activity of the other. Stomach bacteria, pollinators, lichens ++

Predation

Predators often focus on prey that is the better competitor why? Their pops are often higher Thus predation often results in increased variation

Predator prey cycle

Prey increasing, predators increasing Prey decreasing, predators increasing Prey decreasing, predators decreasing Prey increasing, predators decreasing Predator and prey populations cycle (sometimes) Predator population _lags__slightly

Difference between predation and parasitism

Prey is killed outright and used for sustenance -Host is not killed outright -Parasites usually need host for more than just sustenance Place to live_ transportation_

Character displacement

Refers to the phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur -but are minimized or lost where the species' distributions do not overlap. This pattern results from evolutionary change driven by biological competition among species for a limited resource (e.g. food). The rationale for character displacement stems from the competitive exclusion principle, also called Gause's Law, which contends that to coexist in a stable environment two competing species must differ in their respective ecological niche; without differentiation, one species will eliminate or exclude the other through competition

Niche compression

Restriction of niche in response to niche overlap by competing species May be a result of character displacement, resource partitioning bc competition go from fundamental down to realized niche -increase in population size of multiple species -increase in inter competition - decrease in niche breadth - increase in specialization

Scramble competition

Scramble competition is also defined as "a finite resource that is shared equally amongst the competitors so that the quantity of food per individual declines with increasing population density"

Possible outcomes of competition

Sp 1 wins Sp 2 wins Reach a stable equilibrium Reach an _unstable equilibrium

Interactions with other species

Species interact with other species that require the same resources. Consequently, interspecific competition can alter the sizes of many species' populations at the same time. Experiments demonstrate that when species compete for a limited resource, one species eventually drives the populations of other species extinct. -These experiments suggest that competing species cannot coexist (they cannot live together in the same area) because the best competitor will exclude all other competing species.

Batesian mimicry

Species mimics the appearance of an unpalatable or harmful. model is unpalatable, mimic is palatable

Mutualists

Symbiotic (___living together___) Mutualistic_(depend on each other) ++

Species 1 wins

The first scenario is one in which the isocline for species 1 is above and to the right of the isocline for species two. For any point in the lower left corner of the graph (i.e., any combination of species abundances), both populations are below their respective isoclines and both increase. For any point in the upper right corner of the graph, both species are above their respective isoclines and both decrease. For any point in between the two isoclines, species 1 is still below its isocline and increases, while species 2 is above its isocline and decreases. The joint movement of the two populations (thick black arrows) is down and to the right, so species 2 is driven to extinction and species 1 increases until it reaches carrying capacity (K1). The open circle at this point represents a stable equilibrium. In this scenario, species 1 always outcompetes species 2, and is referred to as the competitive exclusion of species 2 by species 1.

Aggregative response

The preference for consumers to spend most of their feeding time in patches containing the highest density of prey. A generally a short term behavioral adjustment where the predator goes to where its food is going to be most abundant thereby ignore areas of low prey populations.

Effect of a heterogeneous habitat

The principle predicts that in an absolutely homogeneous world with a single resource, only a single species could be stably maintained. "No stable equilibrium can be attained in an ecological community in which some r components are limited by less than r limiting factors. In particular, no stable equilibrium is possible if some r species are limited by less than r factors". Levin concludes that biodiversity is a consequence of the spatial and/or temporal heterogeneity of the world in which species can exploit heterogeneous resources and patterns

Resource partitioning (evolution)

The process whereby similar species exploit the limited resources in an ecological area without one species driving the others into extinction. Through natural selection, each species adopts a pattern of resource usage that isn't competitive. One of the driving forces of evolution

Realized niche

The resources a population actually uses The realized niche may be smaller than the fundamental niche because of interspecific interactions such as: Competition Predation "actual job -much smaller job than fundamental niche cause others are filling it already"

Species 2 wins

The second scenario is the opposite of the first; the isocline of species 2 is above and to the right of the isocline for species 1. This graph can be interpreted in much the same way as the previous one, except that the joint trajectory of the two populations when starting in between the isoclines is up and to the left. In this case species 2 always outcompetes species 1, and species 1 is competitively excluded by species 2.

Ambush (sit and wait)

This is a time when deceit helps Strategy may depend on body condition -(cool lizards vs worm) Ambush techniques vary (spider specializing on harvesting ants (trap door)

Functional response

Type I functional response assumes a linear increase in intake rate with food density, either for all food densities, or only for food densities up to a maximum, beyond which the intake rate is constant The relationship between the density of prey and an individual predator's rate of food consumption.

Tool usage

Use an aspect of the environment to help in foraging Probe for termites, under bark for grubs, etc Sea otter, Egyptian vulture, Ant lion, Archer fish

Predation often results in increased ______ ?

Variation Grazing of large herbivores, starfish

Encounter

When two species physically fight for a needed resource

Generalist

Wide niche, use resources of many types Prey switching? Rat Roach Raccoon

Interactions

Will affect structure of the community and the size, density, dispersion of populations within a species -> realm of "social behavior" / _interaction ecology

Disturbance

a temporary change in environmental conditions that causes a pronounced change in an ecosystem. -fires, flooding, windstorms, insect outbreaks and trampling. Earthquakes, various types of volcanic eruptions, tsunami, firestorms, impact events, climate change A species which is well adapted to a particular disturbance is the Jack Pine in boreal forests exposed to crown fires. They, as well as some other pine species, have specialized serotinous cones that only open and disperse seeds with sufficient heat generated by fire. As a result, this species often dominates in areas where competition has been reduced by fire

Intermediate host

an organism that supports the immature or nonreproductive forms of a parasite.

Micro

bacteria, viruses, protozoans

Behavioral defense

behaving in ways that minimize risk (inflating) Under this defense to predation, organisms migrate to avoid predation, use swarms to confuse or avoid the predator, swim in an inconspicuous manner or utilize escape behavior

Müllerian mimicry

both model and mimic are unpalatable

Coexistance

both species' carrying capacities are lower than the other's carrying capacity divided by the competition coefficient -below both isoclines the populations increase and above both isoclines the populations decrease. In this case, however, when the populations of the two species are between the isoclines their joint trajectories always head toward the intersection of the isoclines. Rather than outcompeting one another, the two species are able to coexist at this stable equilibrium point (open circle). This is the outcome regardless of the initial abundances.

So the population growth equation for species 1 including competition w/ species 2 is

dN1/dt = r1N1 {(K1 -[N1+ a (12)N2]) /K1} N= population size K= carrying capacity a= competition coefficient r= intrinsic rate of increase t= time for a (12) do you just multiply competition coefficient of 1 by 2?

Lotka volterra model of predator/ prey interactions

dNh/dt = (rh)Nh-(c)NhNp Nh= prey population Np = predator population r=reproduction c = capture efficiency (rate of predation)

Cont

dNp/dt = (f)(c)NhNp - (dp)Np f = conversion of prey into pred offspring d= predator deaths Nh= prey population Np= predator population c= capture efficiency

Just because 2 spp do not coexist in the field does not mean competition is the cause

different limits of tolerance, physiology, behavior, genetics etc that may (or may not ) be the result of competition

Temporary facultative interspecific

done to different species, not obligatory , temporary

Macro

fleas, ticks, worms, plants

True predator

kill it and eat it Kill prey more or less immediately Consume several or many prey in lifetime

Social defenses

members of the same species or more than one species defending themselves members of your species come to your defense

Inducible response

mounted only when plants sense a threat (used only when you need it)

Direct transmission

move directly from host to host -Spend basically whole life cycle w/ one host Lamprey Dodder Myxomatosis Black - legged tick -barrelia burgdorferi Bacterial spirochete Lyme disease -2 year lifecycle of tick

Predator responses to prey

numerical response aggregative response response developmental response functional response

Interference

occurs directly between individuals via aggression etc. when the individuals interfere with foraging, survival, reproduction of others, or by directly preventing their physical establishment in a portion of the habitat

Preemptive competition

occurs when individuals occupy space and prevent access to resources by other individuals.

Territorial

occurs when mobile organisms protect a feeding or breeding territory. A behavior in which an animal defends a bounded physical space against encroachment by other individuals, usually of its own species.

Chemical defenses

poisons and stings Bombardier beetle mixes two chemicals from separate glands = boiling hot liquid that it sprays - harm predators.

Cannibalism

practice of eating one's own kind Reduce population density Reduce stress Weed out runts Help your own offspring

And for species 2 population growth rate

r2N2 (K2-[N2+a(21)N1])/K2 N= population size K= carrying capacity a= competition coefficient r= intrinsic rate of increase t= time

Niche overlap

situation in an ecosystem in which different species are in competition for the same energy and space resources; in reality, niche overlap in natural ecosystems is typically zero or minimal

Introduced species

species moved by humans to new geographic areas, either intentionally or accidentally

Numerical response

the change in predator density as a function of change in prey density. associated with the functional response, which is the change in predator's rate of prey consumption with change in prey density Change in size of a population of predators in response to change in density of its prey.

Developmental response

the number of prey each individual predator consumes changes as he predator matures. If a predator eats more prey at higher densities, grows more as a consequence and then kills more prey because of its larger size , this is developmental response

Fundamental niche

the set of resources a population is theoretically capable of using under ideal conditions "the resume"

Indirect transmission

using a vector, to act as an intermediate -Different parts of life cycle are spent w/ different hosts -May change behavior of intermediate host at a particular time in order to "get itself transferred" to the next host

Growth rate of prey pop grows

when Np < rh/c

Growth rate of prey pop = 0

when Np = rh/c Np= predator population rh= reproduction of prey c= capture efficiency

Compensatory response

when being fed on consistently, the plant will put a lot of effort to compensate for the damage

Temporary facultative intraspecific

within same species, doesnt necessarily have to do it, only temporary Brood parasites Common in waterfowl Can lay more eggs -Also effectively "spreading around" your kids - safer