Biology - biodiversity ch9-17

When is iteroparity favored?

- environment is stable (stable reproductive and survival rates, stable growth rates) - adults are likely to survive long enough to breed again

describe the three models of succession

1) Facilitation 2) Inhibition 3) Tolerance

key takeaways from the lotka-voltera model regarding species competition

1. competition hurts both competitors but not necessarily by the same amount 2. two competing species can coexist when intraspecific (within) competition is greater than interspecific competition (between) 3. niche differentiation concentrates competition within species, due to a decrease in between-species competition, the lotka-voltera model predicts that niche differentiation will result in co-existence

Heterotrophs vs. Autotrophs

Autotrophs are organisms that can produce their own food from the substances available in their surroundings using light (photosynthesis) or chemical energy (chemosynthesis). Heterotrophs cannot synthesize their own food and rely on other organisms — both plants and animals — for nutrition.

name the three main potential outcomes of competition!

- competitive exclusion - niche partitioning / differentiation - character displacement

Biotic levels of organization

individual, population, community, ecosystem, biome and biosphere

what does direct interference competition refer to

individuals actively preventing others from attaining a resource in a given area or territory a good example would be the example of allelopathy, whereby one plant releases chemicals that poison the soil for others

alpha biodiversity

the diversity within a particular area or ecosystem

Biodiversity Index

used to determine the biodiversity of species in a given ecosystem # species in an area / # individuals in an area

energy loss and trophic efficiency

- each step up in trophic level decreases energy by ~90% - total biomass decreases at each tropic level Note: biomass is the total mass of organisms in a given area

how is the population growth rate calculated in: (a) linear model (b) exponential model (c) logistic model

(a) dN/dt: N2-N1/t2-t1 (b) dN/dt: Nr (birth rates and death rates remain constant whilst the number of individuals is being added in each subsequent point) (c) dN/dt: Nr(1-N/K)

Exotic Species

- a species living outside its native distributional change - brought to a new area by human activity (can be intentional or not) - not necessarily invasive NOTE: most introductions of exotic species fail because abiotic conditions in the new environment may differ and it may be rather difficult to find a mate not to mention the potential to be left outcompeted by existing native species

different scales of biodiversity

- alpha diversity - beta diversity - gamma diversity

Grime's plant classification

- builds onto the k and r-selected models by adding on another dimension - STRESS TOLERANCE -there are three categories: competitive (K-selected), ruderal (r-selected) and stress tolerant

what is the population growth rate doing in each of the three graphs?

- in the linear graph, it is constant - in the exponential graph, it changes over time (increases exponentially) - in the logistic graph, it also changes over time but in a slightly different magnitude (increases then decreases)

density dependent and independent factors: - UV light - cancer risk due to water pollution - likelihood of finding a mate - air pollution from urban areas - competing for limited territory - flooding from a local river - disease transmitted through contact

- likelihood of finding a mate - competing for limited territory - disease transmitted through contact all examples of density DEPENDENT factors

Parasitism

- parasites live on or in hosts - parasites harm the host but DO NOT directly kill it (they typically rely on the host's survival) - the parasite benefits at the cost of the host

what are the unrealistic assumptions of the lotka-volterra model?

- prey population sizes are only entirely dependent on predator populations - predator population sizes are only dependent and influenced by availability of the prey species

Prey have evolved defenses against predators

- pronging/ pronkink (jump high to signal energy & strength) - armor - play dead / fake injury - defensive coloration - cryptic coloration / camouflage - disruptive coloration (also used by predators) - eyespot mimicry - head mimicry - aposematic coloration (signals toxicity)

Predation strategies

- stalking (some predators might not be as fast, therefore instead of chasing after their prey, they stalk their prey until they can get close enough and attack - endurance pursuit (some predators might chase their prey over large distances, running prey to exhaustion) - ambush predation (predator hides and waits) - lures / traps

when is semelparity favored?

- survival rate of offspring is low - small chance that the adult will survive long enough to reproduce again - commonly in highly variable environments (not stable)

parasite life cycle

1. Development 2. Contact with host 3. Gaining suitable niche 4. Survival in host 5. Reproduction 6. Escape from host 7. Repeat some parasites use just one host species and have a free-living life stage during which they are not attached to a host. OTHER parasites use different hosts at different life stages

interference or exploitive competition? 1. Two plants absorb the same limiting nutrient in the soil through their roots. 2. A hummingbird defends an area against other hummingbirds seeking to build a nest. 3. A wasp drains nectar out of a flower, leaving little remaining nectar for pollinators. 4. Two male elephant seals fight for access to mating partners. 5. A fungus releases chemicals into the soil that inhibits the growth of bacteria in the area.

1. Exploitative 2. Interference 3. Exploitative 4. Interference 5. Interference

name all the species interactions and their relative impacts on one another

1. Mutualism - this is a +/+ relationship 2. Commensalism - a 0/+ relationship 3. PREDATION/HERBIVORY/PARASITISM - this is a +/- relationship

impacts of invasive species

1. Niche overlap: when a new species is introduced, it will create niche overlap as the new species competes for resources and space 2. outcompetes native species: this reduces biodiversity 3. kill native species 4. trophic cascade impacts 5. crop loss: invasive species are responsible for multiple economic losses through loss in forest and agricultural productivity, spread of disease that impact humans etc. 6. damage to infrastructure

inter or intraspecific competition? 1. character displacement 2. competitive exclusion 3. directional selection in biological ornaments

1. inter 2. inter 3. intra!!

Exam mistakes:

2. Velvet ants are not ants, but rather a type of wasp that are parasitoids of bees and other wasps. In Texas, there is a complex of 11 different species with the same aposematic coloration: black bodies and bright orange abdomens. All 11 of these species are capable of defending themselves with a powerful (painful) sting. Which of the following describes this situation? - For this question I put E. A mimicry ring containing only Batesian mimics. The reason why I chose this answer was because I thought Batesian and Mullerian mimicry is based off whether or not the "mimicers" are poisonous or not. If they are poisonous and participate in aposematic coloration (brightly colored), then it is Mullerian mimicry, however if it is NOT poisonous yet appears to be due to aposematic coloration, then it is Batesian mimicry. I wasn't sure whether or not stinging would be considered "poisonous" or not. This was clearly a misconception and it is essential to note that mimicry concerns itself with whether or not the species is edible / harmful rather than poisonous or not. Batesian mimicry is a form of protective mimicry, in which a species that is EDIBLE or HARMLESS closely resembles an INEDIBLE or HARMFUL species and therefore is avoided by predators. Mullerian mimicry on the other hand is a natural phenomenon in which two ore more unprofitable (distasteful) species, which share the same predators, have come to mimic one another to their mutual benefit. 4. When an apex predator, such as a bear makes a kill in the forest, they eat the most nutritious parts of the kill and leave the rest. Scavengers, including wolves and vultures soon arrive to eat whatever nutrition is left on the carcass. Wolves, with their claw and teeth weapons, are able to exclude vultures from the carcass. Thus, vultures must wait until wolves have eaten everything they can. Then, vultures eat the remainder of the carcass. Due to this, vultures have evolved traits specialized to extracting the last parts of the carcass with nutritional value that are too difficult for bears and vultures to access, such as bone marrow. Traits specialized to help vultures extract bone marrow are an example of what? - Here, I decided on option C. Resource partitioning when the correct answer was A. Character displacement. The reason why I didn't choose option A was because I had the misconception, that in order for character displacement to occur, we must be speaking about the same species. This however does not make sense as we are talking about intraspecific competition NOT interspecific competition. I believed that it was resource partitioning as all the predators are dividing up the parts of the prey that they can consume, however that is not the case. Coming all the way back to the definitions; Character displacement is the term used to describe an evolutionary change that occurs when two similar species inhabit the same environment. Under such conditions, natural selection favors a divergence in the characters--morphology, ecology, behavior, or physiology--of the organisms. Here, we can clearly see how all the similar species that occupy similar niches - wolves, vultures - evolved different traits to still be able to consume necessary nutrients (in this case the prey). Resource partitioning on the other hand concerns itself with species which divide a niche to avoid competition for limited resources (Note: in this case they do NOT evolve anything but rather divide resources). Animals and plants may evolve to reproduce at different times during the year, feed at different times during the day/night, or use a different part of the environment. 6. A forest fire burns down a large part of the forest. The first species to grow there the next season are the seeds from nearby trees that happened to land there. They do not affect the species that colonize next to them in the next year. What model of succession is being described in this scenario? - In this question, I thought it was describing a facilitation model of succession, as I misread it and thought the pioneer species set the environment up for the next species, however this is not the case. Instead, the pioneer species did NOT affect the species that colonize next to them eventually. The fact that the early colonist did not inhibit colonization by new species nor improve the chances of the next species inhabiting the environment immediately suggests that it is neither an inhibition nor facilitation model. Moreover, in the facilitation succession model, only pioneer species can establish while in the inhibition and tolerance model, any species arriving first can establish. 20. Male dung beetles of a particular species must create dung balls to court females and serve as food for offspring. Males could either find fresh dung to create their dung balls from, or find other males that have already created dung balls, attack them, and steal the dung ball. Males attacking other males of the same species to steal their dung balls is an example of which of the following? -In this question, I correctly identified that it is Intraspecific competition, since it is between individuals of the same species, while interspecific is competition between individuals of different species. Instead of interfetrence however I chose exploitive, as I was under the impression that it is exploitive when one species prevent the other from getting resources by exploiting their and interference is directly interfering with their possibility of gaining the resources by being the first one to take them. The true definitions are as follows: Exploitative competition is an indirect effect that occurs through use of a shared resource and depends on resource availability. Interference competition occurs by obstructing access to a resource and may not depend on resource availability. In this case, the male dung beetles do obstruct access to a resource (courting resource - dung balls) by attacking other males and stealing them.

Symbiosis

A close relationship between two species that benefits at least one of the species.// when individuals of two or more species live in direct and intimate contact with one another - one partner benefits (+) while the other is unaffected (0) NOTE: often a small number of commensals does not affect the host but a large number impose a cost

food webs

A complex diagram representing the many energy pathways in an ecosystem - they depict the MOVEMENT of energy and nutrients

It is thought that climate change contributed to the extinction of Wooly Mammoths. Which of the following describes climate change? An exponential growth factor A density-independent regulator A logistic growth factor A density-dependent regulator

A density-independent regulator - as it is NOT influenced by pop size

Biome

A group of ecosystems that share similar climates and typical organisms // it is on a much broader scale characterized by its vegetation, soil, climate etc.

semelparity

A life history in which adults have but a single reproductive opportunity to produce large numbers of offspring, such as the life history of the Pacific salmon; also known as big-bang reproduction. - "one shot reproduction"

Lotka-Volterra Model

A model of predator-prey interactions that incorporates oscillations in the abundances of predator and prey populations and shows predator numbers lagging behind those of their prey - mathematically model the conditions under which competitive exclusion or coexistence can occur

Parasites vs Parasitoids

A parasite is an organism that lives in or on another species (its host) and benefits by deriving nutrients at the other's expense, resulting in the death of the host. A parasitoid is an insect whose larvae live as parasites that eventually kill their hosts (typically other insects). main difference? parasites harm but do not directly kill the host whilst parasitoids directly kill their host

trophic cascade

A series of changes in the population sizes of organisms at different trophic levels in a food chain, occurring when predators at high trophic levels indirectly promote populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check. Trophic cascades may become apparent when a top predator is eliminated from a system.

Type I survivorship curve

A survivorship curve in which newborns, juveniles, and young adults all have high survival rates and death rates do not begin to increase greatly until old age. Type I typically: -produce few offspring per female -provide extensive care and protection to their young -many large mammals are type I

Batesian mimicry (mutualism? if it slows down predator education?)

A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators. - non toxic species choose to mimic a toxic species NOTE: this does slow down or reverse predator learning

Typically, in plant-mycorrhizae relationships, the plants provide sugar to the mycorrhizae and the mycorrhizae provide water and nutrients to the plant. However, sometimes the plant may stop sharing sugar while continuing to receive water and nutrients. What is being described in this situation? A. A mutualism becomes a parasitism B. A parasitism becomes a mutualism C. The relationship is a mutualism in both situations D. A symbiosis ceases being symbiotic.

A. A mutualism becomes a parasitism

Which of the following best describes resource partitioning? A. Dividing resources to avoid competition for limited resources in ecosystems B. Sharing resources to avoid competition for limited resources in ecosystems C. Dividing resources to promote competition for limited resources in ecosystems D. Sharing resources to promote competition for limited resources in ecosystems

A. Dividing resources to avoid competition for limited resources in ecosystems

there are a huge number of parasitoid wasps prevalent in our environments. A species will typically specialize on one host species.. Parasitoid wasps are a polyphyletic group - what does that suggest about evolution of parasitoidism? A. parasitoidism in parasitoid wasps is the result of convergent evolution B. parasitoidism in parasitoid wasps is an ancestral trait C. parasitoidism in parasitoid wasps evolved only once D. None of the above

A. Parasitoidism in parasitoid wasps is the result of convergent evolution

the mortality rate of organisms following a type III survivorship curve is: A. lower after the organisms become established B. fairly constant throughout their life C. age is not a factor D. higher in post reproductive years

A. lower after the organisms become established

Match the terms to their definitions. Terms: Alpha diversity, beta diversity, gamma diversity Definitions: A. the species diversity between two communities or ecosystems. B. the total species diversity in a landscape. C. the species diversity in a site at a local scale.

Alpha diversity - C. the species diversity in a site at a local scale. beta diversity - A. the species diversity between two communities or ecosystems. gamma diversity - B. the total species diversity in a landscape.

Predation

An interaction in which one organism kills another for food - one organism, the predator, kills and eats another organism, its prey NOTE: predators can limit the population and distribution of prey BUT ALSO prey can limit the population and distribution of predators!

Which of the following is the best example of commensalism? A. A nematode is ingested by a human and attacks the intestinal lining in order to obtain nourishment. B. An oxpecker (a type of bird) lands on a rhinoceros and eats parasites such as ticks from its body, getting nourishment in the process. C. Barnacles settle on the body of a large whale, who remains undisturbed. D. A shrimp constructs a burrow for goby fish and the fish defends the shrimp from higher-level consumers.

B. An oxpecker (a type of bird) lands on a rhinoceros and eats parasites such as ticks from its body, getting nourishment in the process.

Which of the following is NOT an example of parasitism? A. Leeches attach to a salmon and suck its blood to obtain nutrients. B. Barnacles attach themselves to the surface of whales to settle down and filter water. C. Plasmodium enters a human's bloodstream via a mosquito bite and causes malaria. D. A fungus colonizes a leaf surface and extracts nutrients from the leaf.

B. Barnacles attach themselves to the surface of whales to settle down and filter water.

A farmer is experimenting with different methods to get the best yield from their crops. They discover that their soybeans are capable of growing on their own, but when mycorrhizae are introduced, the soybeans grow larger and produce a greater crop yield. The relationship between the soybean and mycorrhizae is best described as: A. Obligate mutualism B. Facultative mutualism C. Commensalism D. facultative parasitism

B. Facultative mutualism

In the inhibition model, which species is most likely to become dominant? A. The species that arrives first B. The species that is the strongest competitor C. The species that is the most shade-tolerant D. The species that can survive with the fewest resources

B. The species that is the strongest competitor NO A. The species that arrives first

A turtle is equally likely to die at 10 years and at 100 years. Which type of survivorship curve are they most likely to exhibit, based on this statement? A. Type I B. Type II C. Type III D. Type IV

B. Type II

When will biodiversity be highest? A. Where there is no disturbance in the ecosystem B. When there is an intermediate level of disturbance in the ecosystem C. When there is a high level of disturbance in the ecosystem D. When there are variable levels of disturbance in the ecosystem

B. When there is an intermediate level of disturbance in the ecosystem (as stated by the IDH model)

How does the structural complexity of a landscape influence the biodiversity of the community living there? Increased structural complexity... A. increases biodiversity as it is easier for keystone species to dominate B. increases biodiversity as there are more niches available C. decreases biodiversity as there are fewer available resources D. decreases biodiversity because it makes it harder for organisms to live

B. increases biodiversity as there are more niches available

batesian vs mullerian mimicry

BATESIAN - a form of mimicry in which an edible animal is protected by its resemblance to a noxious one that is avoided by predators MULLERIAN - a form of mimicry in which two or more noxious animals develop similar appearances as a shared protective device

biotic vs abiotic factors

Biotic factors are influences on organisms in an ecosystem. Abiotic factors are nonliving. Biotic factors are living organisms, while abiotic factors are not alive, like wind, temperature, etc. abiotic (non-biological): climate (precipitation, temperature, seasons, geology (bedrock, physical features, hydrology, soils, disturbance (natural, human) biotic (biological): species interactions (competition, predation, mutualism, facilitation, parasitism), distributions and quantity if species, invasive or keystone species

Which of the following species is most likely to be an r-selected species? A. A species in which the individuals reach sexual maturity relatively late in life. B. A species that experiences intense intraspecific (outside species NOT within) competition. C. A species that produces a large number of offspring at one time. D. A species that provides a lot of parental care to their offspring.

C. A species that produces a large number of offspring at one time.

What level of diversity would an ecologist use to describe the diversity of the entire planet? A. Alpha B. Beta C. Gamma D. Omega

C. Gamma

What is the difference between primary and secondary succession? A. Primary succession always occurs before secondary succession B. Primary succession occurs more often than secondary succession C. In primary succession a brand new community is founded whereas in secondary succession the community is influenced by the pre-existing community D. In primary succession, only pioneer species can establish whereas in secondary succession only climax species can establish.

C. In primary succession a brand new community is founded whereas in secondary succession the community is influenced by the pre-existing community D. climax species is not a thing

What is the primary prediction of the Lotka-Volterra models? A. Predator population sizes will always be higher than prey population sizes. B. Predator and prey population sizes do not affect each other. C. Predator and prey population sizes cyclically influence each other. D. Predators influence prey population sizes but prey do not influence predator's population sizes.

C. Predator and prey population sizes cyclically influence each other.

Which of the following best describes character displacement? A. Dividing resources to avoid competition for limited resources in ecosystems B. Species occupy the same niche C. Trait differentiation resulting from resource partitioning D. Species feed on the same food

C. Trait differentiation resulting from resource partitioning

Female orange sulfur butterflies lay thousands of eggs, the vast majority of which die due to disease, competition, or predation. What survivorship curve best describes orange sulfur butterflies? A. Type I B. Type II C. Type III D. Not enough information to tell

C. Type III

Once again.. definition of carrying capacity (K)

Carrying Capacity (K): the maximum number of individuals a particular habitat can sustain indefinitely given the amount of available resources NOTE: it will ALWAYS be the uppermost point on the curve as it is the maximum number!!

What is an invasive species? A. Any non-native species introduced to a new area. B. Any species that becomes dominant in a community. C. Any species that negatively impacts a community. D. A non-native species that negatively impacts a community.

D. A non-native species that negatively impacts a community.

How can invasive species impact their new ecosystems? A. By causing disease B. By outcompeting native species C. By consuming native species D. All of the above

D. All of the above

What are the possible outcomes of a species being introduced to a new continent it did not evolve on? A. It could fail to establish and not impact the ecosystem B. It could establish and alter the ecosystem dynamics C. It could establish and outcompete native species and drive them to extinction D. All of the above

D. All of the above!!

How do exotic species get introduced to new regions? A. On accident through human activity. B. Intentionally by humans as pets. C. Intentionally by humans as ornamental species. D. All of the above.

D. All of the above.

In a region in Texas, biologists observed that two highly venomous snakes have similar markings deter owl predators. The biologists sequenced the genomes of the species and found that they are distantly related; they are separate species belonging to different genera. These snakes are an example of what predation defense? A. Batesian mimicry, because it involves a nontoxic species that resembles a toxic species. B. Bestesian mimicry because the two species are distantly related. C. Mullerian mimicry because it involves an extremely toxic species that resembles a non-toxic species. D. Mullerian mimicry because it involves different species that both produce toxins and display similar warning coloration.

D. Mullerian mimicry because it involves different species that both produce toxins and display similar warning coloration.

A wasp lays its eggs in a caterpillar. For a while, the caterpillar is unaffected and grows normally. The wasp eggs hatch inside the caterpillar and when the wasp larvae reach a specific developmental stage, they consume the caterpillar from the inside out and burst from the caterpillar's body, killing it. This scenario best describes which of the following species interactions? A. Predation B. Herbivory C. Parastism D. Parasitoidism E. Commensalism

D. Parasitoidism

In a grazing oceanic food web, who would likely be the primary producer? A. Fungi B. Protist C. Krill D. Phytoplankton

D. Phytoplankton because fungi would be part of the detritivore food web and krill plus protist are not plants

Which of the following terms describes the first species to colonize newly-formed land, such as the result of a volcanic eruption? A. Climax community B. Keystone species C. Foundation species D. Pioneer species

D. Pioneer species climax community - is when a steady state or equilibrium is reached keystone species -A keystone species is an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. Keystone species have low functional redundancy (later chapter)

What is the difference between a fundamental and realized niche? A. Fundamental niche is based on fewer variables than realized niche. B. Fundamental niche is for animals and realized niche is for plants. C. Realized niche is more complex than fundamental niche. D. Realized niche accounts for competition whereas fundamental niche does not.

D. Realized niche accounts for competition whereas fundamental niche does not.

What is an assumption of the Lotka-Volterra model? A. Population sizes are constant over time. B. Prey population size is unaffected by predator population size. C. Mathematical equations cannot explain biological phenomena. D. The number of prey grow exponentially in the absence of predators.

D. The number of prey grow exponentially in the absence of predators

density dependent and independent factors

Density-dependent factors have varying impacts according to population size. Different species populations in the same ecosystem will be affected differently. Factors include: food availability, predator density and disease risk. Density-independent factors are not influenced by a species population size.

What causes character displacement to occur? A. Competition B. Niche overlap C. Resource partitioning D. A and B E. A, B, and C

E. A, B, and C

How is mutualism different from commensalism or parasitism? A. Mutualism is where both interacting species benefit, while in commensalism, one species benefits and the other species is unaffected. B. Mutualism is where both interacting species benefit, while in parasitism, one species benefits and the other species is unaffected. C. Mutualism is where both interacting species benefit, while in parasitism, one species benefits and the other species is harmed. D. Mutualism is where both interacting species are harmed, while in parasitism, one species benefits and the other species is harmed. E. A. and C.

E. A. and C.

Which of the following terms decreases as the population size approaches carrying capacity? A. r B. rN C. dN/dt D. 1-N/K E. Both C and D

E. Both C and D

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 - inevitably, one competitor out of the two will be the stronger competitor while the other will be the weaker one. - the weaker competitor might be entirely excluded from that portion of the niche where overlap occurs - this may lead to extinction of one of the competitors · The competitive exclusion principle states that two species cannot occupy the same niche in a habitat. In other words, different species cannot coexist in a community if they are competing for all the same resources Competitive exclusion may be avoided if one or both· of the competing species evolves to use a different resource, occupy a different area of the habitat, or feed during a different time of day

pioneer species

First species to populate an area during primary succession, short lived and fast growing, set up area for climax species, withstand harsh environments, can germinate well / high dispersal rates, produce a large number of seeds, generalists

character displacement

Galapagos finches example: Galapagos finches were occupying the same island and underwent complete niche overlap. In order to survive and co-exist, they became specialized to consumer specific seeds and / or food. For each specialized species, their beak shape was selected to maximize efficiency of consuming that specific food. This happened to several finches - adaptive radiation. specializing on different types of food changed selection pressures acting on the beaks leading the beaks to evolve different shapes and sizes. this is also called CHARACTER DISPLACEMENT - Character displacement is trait differentiation that occurs when similar species that live in the same geographic region and occupy similar niches differentiate in order to minimize niche overlap and avoid competitive exclusion. - Character displacement is 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. summary: character displacement is when resource partitioning changes the resources species use which leads to evolutionary changes in traits

generalists vs specialists

Generalists are able to use a wide array of habitats and resources. - can occupy a broad fundamental niche but typically are poor competitors Specialists are organisms that require specific requirements. - occupy a more limited fundamental niche - typically are strong competitors for that niche there's often a tradeoff between tolerance of harsh environments and competitive ability

where does biodiversity tend to be higher why do you think so

In areas with greater geographic variation aka lower latitudes aka near the equator Such areas may have: - receive more energy from the sun - more energy to start with (trophic levels) - climatic variables (environmental harshness) - complexity of environment (available niches) provides more habitats Note: Environmental harshness is the surrounding condition an individual is living in, which can be measured, for example, by local mortality/morbidity and availability of the resources

Which of the following describes lichens? A. A mutualistic relationship between a fungus and an algae or bacteria B. A commensalistic relationship between a fungus and an algae or bacteria C. A fungus that parasitizes an algae or bacteria D. A bacteria that parasitizes a fungus

In lichen, the algal cells are fully surrounded by the fungus. The sugars produced by the algae through photosynthesis provide nourishment for both organisms. The physical structure of the fungus protects the algae from the elements and makes certain nutrients in the atmosphere more available to the algae

intra vs interspecific competition

Intra: between members of same species Inter: between members of different species

Which of the following traits of bison indicates that they are a K-selected species? A. Bison are relatively large (30-70 pounds) when they are born. B. Bison graze on grass C. Bison have thick fur to protect from cold weather D. Male bison physically compete with each other for mates.

K-selected -> competitive -> long lived, slow growth, low fecundity, resemble climax species.. .A. Bison are relatively large (30-70 pounds) when they are born. Recall that K-selected species are usually mammals with large bodies

define the following elements: N, r, K

N = population size K = carrying capacity = the maximum number of individuals a particular habitat can sustain indefinitely given the amount of available resources r = intrinsic growth rate

What is the difference between species richness and species evenness A. Species richness is a more accurate measure of biodiversity B. Species evenness is a more accurate measure of biodiversity C. Species richness only counts the number of species present while species evenness accounts for the relative abundance D. Species evenness only counts the number of species present while species richness includes the relative abundance

NOT A or B as both are relatively accurate measures of biodiversity, which is why they are both part of the biodiversity index! D is flipped C. Species richness only counts the number of species present while species evenness accounts for the relative abundance

Where is biodiversity the highest for all taxa? A. Near the equator B. Near the poles C. At high latitudes D. In the ocean

One of the oldest observed patterns in ecology is that species biodiversity in almost every taxonomic group increases as latitude declines. In other words, biodiversity increases closer to the equator hypotheses to explain why biodiversity increases closer to the equator: - the greater age of the ecosystems in the tropics versus temperate regions that were largely devoid of life or drastically impoverished during the last glaciation = The idea is that greater age provides more time for speciation. - the increased energy the tropics receive from the sun versus the decreased energy that temperate and polar regions receive. - the complexity of tropical ecosystems may promote speciation by increasing the heterogeneity, or number of ecological niches, in the tropics relative to higher latitudes. The greater heterogeneity provides more opportunities for coevolution, specialization, and perhaps greater selection pressures leading to population differentiation. - the tropics are more more stable than temperate regions, which have a pronounced climate and day-length seasonality. The tropics have their own forms of seasonality, such as rainfall, but they are generally assumed to be more stable environments and this stability might promote speciation A. Near the equator / at lower latitudes / away from the poles

Which of the following tertiary predators do you expect to find the highest biomass of A. Polar bears in the Arctic B. Leopards in equitorial Africa C. Grizzly bears in Canada

Recall that: One factor in determining species richness is latitude, with the greatest species richness occurring in ecosystems near the equator, which often have warmer temperatures, large amounts of rainfall, and low seasonality. The lowest species richness occurs near the poles, which are much colder, drier, and thus less conducive to life. Therefore: B. Leopards in equitorial Africa

iteroparity

Reproduction in which adults produce offspring over many years; also known as repeated reproduction.

native species

Species that normally live and thrive in a particular ecosystem // they are species that normally live in a particular community. - they have co-evolved with other species in the community and occupy a specific niche - they have native predators, competitors, and pathogens that help keep their population sizes in check

Mutualism vs Symbiosis

Symbiosis refers to a close and prolonged association between two organisms of different species. Mutualism refers to mutually beneficial interactions between members of the same or different species. Mutualistic interactions need not necessarily be symbiotic.

Biodiversity

The amount of biological or living diversity per unit area. It includes the concepts of species diversity, habitat diversity and genetic diversity. // it describes the numbers and kinds of species in a location

trophic levels

The hierarchical levels of the food chain through which energy flows from primary producers to primary consumers, secondary consumers and so on. // describe steps along the food web

What does trophic inefficiency EXPLAIN

Trophic inefficiency explains why there is more biomass & biodiversity at low latitudes how? more energy input in the system (in this case via sunlight) means more trophic levels can be supported and therefore more biodiversity is possible

what are the three types of survivorship curves

Type I Type II Type III

what is a disturbance of a community

a force external to the community that is relatively discrete in time that changes resources or the physical environment (common example is forest fires) NOTE: disturbances are normal and regular to occur. Human activity can influence the severity and frequency of such disturbances

facilitation model of succession

a model of successional change in which early colonists improve conditions for other species that subsequently colonize.. it assumes that only early-successional species can colonize a recently disturbed site and these early colonizers alter the site in ways that enable later successional species to establish

inhibition model of succession

a model of successional change in which early colonists inhibit colonization by new species.. it assumes that any species can colonize a recently disturbed site and THEY are the ones to prevent others from establishing. over time, short lived (fast growing) species are replaced by long lived (slow growing) species - this applies mainly to secondary succession!

Type II survivorship curve

a pattern of survival over time in which there is a relatively constant decline in survivorship throughout most of the life span // constant death rate throughout lifespan - all ages equally likely die Type II typically: - produce a moderate number of offspring per female - provide some parental care - many birds, some rodents, many invertebrates, some lizards and SOME annual plants

keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically. It has a disproportionate effect on community structure

A detrital food web

a type of food web that is supported by dead or decaying organisms rather than by living autotrophs; these are often associated with grazing food webs within the same ecosystem NOTE: decomposers break down dead and decaying organisms and detritivores consume organic detritus

tolerance model of succession

all species can initially settle, but then competitively poorer species disappear as they are replaced by better competitors.. it assumes that any species can colonize a recently disturbed site and they have no influence on others' ability to establish. Over time, species that are weaker competitors for resources are replaced by species that are stronger competitors - Also applies mainly to secondary succession!

is alpha diversity more similar to species richness or species evenness measures of biodiversity What level of diversity would an ecologist use to describe the species richness of their backyard? A. Alpha B. Beta C. Gamma D. Omega

alpha diversity refers to the diversity within a particular area or ecosystem, and is usually expressed by the number of species (i.e., species richness) in that ecosystem. THEREFORE.. A. Alpha

Amensalism and Commensalism

amensalism: a relationship between organisms of two different species in which one is unaffected and the other is negatively impacted by the association - one partner is harmed (-) whilst the other is unaffected comensalism: one partner benefits (+) while the other is unaffected

invasive species

an introduced exotic species that is so successful they become a nuisance to humans. It thrives in its new environment and adversely affects its new ecosystem

r in logistic growth model

birth rate - death rate // intrinsic growth rate

Mutualism

both organisms benefit (+,+)

facultative mutualism

both species can survive alone - partners CAN survive outside the relationship

why have toxic species evolved to be brightly colored?

bright colors speed up predator education!!

key terminology

carrying capacity (K), birth rate - death rate (r), density dependence and density independence

K in logistic growth

carrying capacity // how many individuals of a species are able to be sustained by a specific environment

predator-prey relationship

classic example: Canadian Lynx (predator) and snowshoe hare (prey) The Lotka-Volterra model predicts that as the hare numbers increase, there is more food available for the lynx, allowing the lynx population to increase as well. When the lynx population grows to a threshold level, however, they kill so many hares that hare population begins to decline, followed by a decline in the lynx population because of scarcity of food. When the lynx population is low, the hare population size begins to increase due to low predation pressure, starting the cycle anew.

what does indirect exploitive competition refer to

consumption of limited resources by individuals making it more difficult for others to attain the resource this is also known as scramble competition

area of the logistic growth equation that contributes density-dependence?

dN/dt (growth rate): Nr (expo/increase) (1-N/K) (decrease)

population growth rate

dN/dt = population growth = rate of change in the number of individuals in the population or density of the population In other words, growth rate is the slope of the line (or the derivative)

IF r=2 and pop size is 10 species per cm2, then what is the growth rate assuming we are looking at an exponential graph

dN/dt: Nr: (10)(2) = +20 species per cm2/ per unit time

survivorship curves depict..

death rate across a lifespan

data analyzed

density, abundance, birth rates and death rates

what factors can impact population size

disease, competition, parasites, predation..

climax species

dominant species of plants and animals that come to live in an area at later successional stages, slow growing long lived species, strong competitors (specialists), can germinate and grow with limited resources (limited light, limited space etc.)

Type III survivorship curve indicates

high juvenile mortality and low mortality in older adults // high death rate of offspring but once established, high likelihood of surviving to old age Type III typically: - produce a large number of offspring per female - provide little / no parental care - long lived plants, many fishes, most marine invertebrates and fish

endemic species and biodiversity hotspots

endemic species that are native to and found only within a limited area Biodiversity hotspots are geographical areas that contain high numbers of endemic species.

Net Consumer Productivity (NCP)

energy content available to the organisms of the next trophic level (net consumer productivity / assimilation ) x 100

niche

environmental conditions that define the requirements for a species to persist // Full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions

ecology

examines how organisms interact with one another and their environment

types of growth curves

exponential (increases exponentially, growth rate is proportional to population size), logistic (increases then decreases), and linear (straight line, a constant number of individuals is being added over time) NOTE: y is always the density or amount while x is the time

pioneer species and its life history traits

first species to colonize an area during succession after a disturbance (they set-up the environment to be colonizable by other species later on..) species that colonize quickly may have: - far dispersal distances to travel in from nearby areas unaffected by disturbance - hardy, tolerant dormant species (fire resistant seeds) - quick growth in high light environments

A grazing food web

food web in which most energy is transferred from producers to grazers (herbivores)

mimicry rings (mutualism)

groups of species that benefit from defensive mimicry - form when multiple species mimic each other summary: large assemblages of species, both mullerian and batesian mimics, exhibiting the same color pattern.

what happens to the pop growth rate (dN/dt) when N increases

increases THEN decreases

Herbivory

interaction in which one animal feeds on producers / consumption when the "prey" is plants

What does the term r represent in exponential population growth equations? r represents the...

intrinsic rate of increase in the population put simply, this rate can be understood as the number of births minus the number of deaths per generation time—in other words, the reproduction rate less the death rate

common characteristics of invasive species

invasive species in general: - have few predators, competitors, parasites or diseases in the new environment - have high reproductive rates - are generalists - asexual or 'selfing' reproduction

In the logistic model growth rate equation, what happens to the second term (1-N/K) as N increases

it decreases (this part of the equation accounts for the part of the logistic growth model, whereby the pop growth rate decreases)

In the logistic model growth rate equation, what happens to the first term (rN) when N increases

it increases (this part of the equation accounts for the part of the logistic growth model, whereby the pop growth rate increases)

summary II

linear - a constant number of individuals are being added over time - population growth rate is CONSTANT - N2-N1/t2-t1 exponential - an increasing number of individuals are being added over time - population growth rate is increasing - Nr Note: always choose the highest K when identifying it on an exponential graph logistic - an increasing number of individuals are added initially, then a decreasing number of individuals are added over time - Nr(1-N/K)

obligate mutualism

mutualism in which at least one species can't survive without its partner - partners CANNOT survive outside the mutualism

breakdown of the logistic model (2 main parts to it)

part 1: increasing - resources are NOT constraining growth and the population can grow at its maximum rate, which is (r) part 2: decreasing - reaching carrying capacity, this is called density-dependent growth, as the growth rate depends on the population density therefore, in the logistic model, the population growth rate depends on population size

predation is __ dependent

predation is density-dependent, as it increases when population sizes of prey are high

stress tolerant species

predominate under conditions of low disturbance and high stress they have: -adaptations that help them survive periods of scarcity -exploit ephemeral (temporary resources) -slow growth, long lifespan -high juvenile mortality (aka type III survivorship curve) NOTE: Disturbances are events, like tornados, wildfires or floods that cause marked changes to the impacted area. Stressors, like pathogens or water stress are dynamics that impair or comprise the function or productivity of the system.

summary of r and k-selected

r-selection -many offspring / high fecundity therefore -low investment -low survival rate (thus the many offspring to account for the high death rate) -fast growth / short lifespan k-selection -few offspring -large investment -long lifespan -high survival rate -slow growth NOTE: these represent extrema of the spectrum

Limitation of exponential (and linear) models

the exponential model specifically, assumes and predicts that the growth rate will continue to accelerate as the population increases. Recall that: an exponential model shows an increasing number of individuals being added over time, so the population rate is increasing 'continuously' the issue with this however is that an ecosystem can ONLY support so many individuals based on space and resources that is why the CARRYING CAPACITY (K) was put in the picture and why the logistic model may most closely resemble realsitic population growth - the logistic model accounts for population growth by carrying capacity - carrying capacity (K): the max number of individuals an environment can sustain

How does competitive exclusion affect the niche of the species that is excluded?

the fundamental niche is unaffected but the realized niche is reduced

difference between logistic and exponential models

the logistic model accounts for resource limitations whereas the exponential model does not

r-selection and k-selection

r-selection: is the selection that has maximized intrinsic reproductive rate (NOTE: if r < 0 then the population is declining, if r > 0 then the population is increasing and if r = 0 then the population is stable) r-selected traits: (fast growing, short lived) -high fecundity (the ability to produce an abundance of offspring or new growth; fertility.) -quick growth, fast reproduction early in life -poor competitors for resources -short lifespans -small body size (little investment in growth) -low parental investment in offspring - closely resembles Type III survivorship and pioneer species as r-selected species are most successful in recently disturbed areas k-selection: is the selection that has maximized success in crowded communities and when the population is near the carrying capacity k-selected traits: -low fecundity -slow growth, first reproduction late at life -strong competitors for resources -long lifespans -large body size -large parental investment in offspring -most successful in environments that face little disturbance like climax species, resemble type I survivorship In summary: R selected models demonstrate high resistance towards disturbances, which resembles those species of late succession as they must accommodate to the already established environment and survive in competition towards early succession species which were first established there and allows for other species to then form. K selected resembles the early succession species

what does "r" mean? what does an r of 3 signify?

rate of intrinsic population increase; it is the birth rate - death rate AND it is intrinsic to the species meaning it does NOT change It shows that the given population triples in size per specified time period // population size triples

r and k-selection

reproductive trade-offs are described in terms of r and k-selection the r and k-selected theory arose from the disturbance theory and the logistic growth model:

ecologists

seek to find patterns and explain them in nature

What is the primary difference between iteroparity and semelparity? A. The number of offspring produced. B. The number of times an individual reproduces during its lifetime. C. The amount of parental care provided to offspring. D. The amount of resources invested in reproduction.

semelparity (A life history in which adults have but a single reproductive opportunity to produce large numbers of offspring, "one shot reproduction") B. The number of times an individual reproduces during its lifetime.

opportunistic cleaner fish

small fish or shrimp eat parasites off of large fish; they get a meal (+) and the client gets parasites removed (+) HOWEVER sometimes these opportunistic cleaners accidentally bite off a scale or skin from the fish; cleaners get a better meal (+) clients get injured (-)

protection from herbivory

structural defenses (spines and trichomes), mimicry (when plants mimic other organisms), plant behavior, chemical defenses fun fact: many of the spices that we enjoy evolved as herbivore defense mechanisms

population dynamics

studies the size and age compositions of populations and the environmental processes affecting them

determine which species are at which trophic level in this example

sun - primary energy source grass - primary producer mouse - primary consumer hawk - secondary consumer snake - tertiary consumer (apex)

Biomes are typically characterized by

temperature and rainfall

What can the Grime's Plant Classification be also called

the CSR classification model (the competitive, ruderal, stress-tolerant) -- often species in the same biome share similar strategies in the CSR model

when prey population is high, what is happening to the predator population based on the lotka-volterra model

when prey population is high, there is a lot of 'food' available for the predators to feed on. This in turn increases the number of predators present in the environment, however now that the numbers of predators are high, the numbers of prey will inevitably reduce as they are over-hunted by the predators

n-dimensional hypervolume

the multi-dimensional space of resources (i.e. light, nutrients..) used or occupied by a species - proposed by hutchinson

beta diversity

the number of species that differ in occurrence between two habitats

density

the total number of individuals in a population that exist within a defined area // total number of individuals per unit area can be calculated using the formula: number of individuals (n) / unit area or volume (A)

endosymbiotic theory

theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms

abundance

total number of individuals in a population

Mullerian mimicry (mutualism)

toxic species mimic one another - they share the cost of educating naive predators - two or more harmful species that are not closely related, and share one or more common predators, have come to mimic each other's warning signals

control of invasive species

via: - treatment with chemicals - physical removal - biocontrol: use other organisms (pathogens) to feed on them // introduce a predator or pathogen of the invasive species to reduce or eliminate it

Facilitation

- ALWAYS occurs during primary succession (the succession that begins new communities and it is uninfluenced by prior communities) -new bedrock (meaning no soil) can only really be inhabited by a few, tolerant species - over time, those organisms make the environment more habitable as they break up the rock into soil, add nutrients, etc. IN OTHER WORDS.. pioneer species make bedrock more habitable for other species) - as the environment becomes more habitable, new species that are less stress-tolerant but better competitors move in

summary

- Changes in community structure and composition over time are induced by environmental disturbances such as volcanoes, earthquakes, storms, fires, and climate change. - Communities with a stable structure are said to be at equilibrium. Following a disturbance, the community may or may not return to the equilibrium state. - In primary succession, newly exposed or newly formed land is colonized by living things; in secondary succession, part of an ecosystem is disturbed and remnants of the previous community remain. Thus, disturbance can initiate successional change. - Species that are well adapted for exploiting disturbance sites are referred to as pioneers or early successional species.

FUNDAMENTAL vs REALIZED NICHE

- Fundamental niche is the entire set of conditions under which an animal (population, species) can survive and reproduce itself - IT IS ONLY IF THERE ARE NO OTHER SPECIES INTERFERING - Realized niche is the set of conditions actually used by given animal (pop, species), after interactions with other species (predation and especially competition) have been taken into account. fundamental - the niche a species could potentially occupy in the absence of competition realized - the niche a species actually occupies due to competitive exclusion · Realized niche accounts for competition whereas fundamental niche does not

Define succession and subsequently, community succession

- It is the way communities recover after a disturbance or the change in structure and species composition of a community over time - community succession: is the repeatable change in community composition through time following a disturbance

You walk through a forest and identify 100 individual amphibians within 4 different species. What is the biodiversity index, what is the species richness, and what level of biotic focus are you working at?

- biodiversity index = # of individuals / # of species = 100/4 -species richness is 100 - biotic level: community (NOTE: remember the acronym IPCE B & B)

alternate definitions of: competitive exclusion, niche partitioning and character displacement

- competitive exclusion: when one species is driven to local extinction through competition with another species with an overlapping niche - niche partitioning: the subdividing of resources or habitat to minimize competition between two or more species // slight variations in two species' use of resources that allow them to coexist - character displacement: when two species with overlapping phenotypes undergo directional selection, in opposite directions, due to competition // two species experiencing niche overlap evolve slightly different traits to take advantage of slightly different resources

Food webs - INDIRECT interactions

- food webs can be very complex - there are many indirect interactions between species - such interactions are extremely important in a food web. Why? - because they influence all the other organisms in a trophic level - "the enemy of my enemy is my friend" i.e. primary producer - Seaweed primary consumer - sea urchin secondary consumer - sea otter The more seaweed available, the more sea urchins and the more sea otters. If, say, the amount of seaweed is dramatically reduced, then the number of sea urchins will decrease immediately and so will the number of sea otters - direct negative effect; when sea otters feed on sea urchin OR when sea urchin feed on seaweed - indirect negative effect; when sea otters reduce the amount of sea urchins by feeding on them and thus reducing the number of seaweed prey indirectly

species that colonize late in succession may have:

- low dispersal - slow growth - tolerant of low-light conditions many of these traits are subject to trade-offs: it may not be possible to be both fast growing and tolerant to low light conditions

where does most of the energy lost go

- some of it goes towards waste/ excrition meaning to form feces - some of it goes towards aerobic / cellular respiration - a little fraction of what's left goes towards growth

how do we measure biodiversity

- species richness: HOW MANY DIFFERENT SPECIES are there (just count) - species evenness: takes into account the RELATIVE ABUNDANCES of each species

niche differentiation aka niche partitioning and 'spacial niche partitioning' and 'temporal niche partitioning'

- species use different parts of the environment due to interspecific (inter = between) competition - species use different parts of the environment to co-exist - in order to avoid competition and / or competitive exclusion due to niche overlap, species alter their use of the niche by dividing resources among them spacial - use of the same resources but in a slightly different physical area temporal - use the same resource but at different times · In summary: Niche differentiation (also known as niche separation and niche partitioning) refers to the process by which competing species use the environment differently in a way that helps them to coexist. When two species differentiate their niches, they tend to compete less strongly, and are thus more likely to coexist. Species can differentiate their niches in many ways, such as by consuming different foods, or using different areas of the environment..

what impacts species richness

- the number of species present in an area - One factor in determining species richness is latitude, with the greatest species richness occurring in ecosystems near the equator, which often have warmer temperatures, large amounts of rainfall, and low seasonality. The lowest species richness occurs near the poles, which are much colder, drier, and thus less conducive to life.

Biosphere

Consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere - all of earth's biotic and abiotic components

What causes niche partitioning to occur? A. Competition B. Niche overlap C. Speciation D. A and B E. A, B, and C

D. A and B

Why is trophic level transfer efficiency less than 100%? A. Heat loss B. Imperfect ingestion C. Cellular respiration D. All of the above

D. All of the above

In the tolerance model ... A. Earlier species make the environment more hospitable for other species B. Earlier species make the environment more difficult for other species C. Early species completely prevent other species from establishing In the tolerance model D. Earlier species do not directly affect the success of later species

D. Earlier species do not directly affect the success of later species

Which statement accurately contrasts heterotrophs from autotrophs? A. Heterotrophs can photosynthesize, while autotrophs cannot. B. Heterotrophs cannot photosynthesize, while autotrophs can. C. Heterotrophs cannot obtain their own food, while autotrophs can. D. Both A and C E. Both B and C

E. Both B and C

gentic diversity

Genetic diversity or variation is the raw material for adaptation in a species. A species' future potential for adaptation depends on the genetic diversity held in the genomes of the individuals in populations that make up the species. The same is true for higher taxonomic categories. A genus with very different types of species will have more genetic diversity than a genus with species that look alike and have similar ecologies. If there were a choice between one of these genera of species being preserved, the one with the greatest potential for subsequent evolution is the most genetically diverse one. Many genes code for proteins, which in turn carry out the metabolic processes that keep organisms alive and reproducing. Genetic diversity can be measured as chemical diversity in that different species produce a variety of chemicals in their cells, both the proteins as well as the products and byproducts of metabolism. This chemical diversity has potential benefit for humans as a source of pharmaceuticals, so it provides one way to measure diversity that is important to human health and welfare.

what does the intermediate disturbance hypothesis state and based on what premises is this hypothesis built

IDH suggests that local species diversity is maximized when ecological disturbances are neither too rare nor too frequent - At low levels of disturbance, more competitive organisms will push subordinate species to extinction and dominate the ecosystem. - At high levels of disturbance, due to frequent forest fires or human impacts like deforestation, all species are at risk of going extinct. - According to IDH, at intermediate levels of disturbance, diversity is thus maximized because species that thrive at both early and late successional stages can coexist. I - IDH is a non-equilibrium model used to describe the relationship between disturbance and species diversity - IDH is based on the following premises: 1. ecological disturbances have major effects on species richness (the total number of different species) within the area of disturbance, 2. interspecific competition results in one species driving a competitor to extinction and becoming dominant in the ecosystem (recall that: intraspecific is competition between individuals of the same species, while interspecific is competition between individuals of different species.) 3. moderate ecological scale disturbances prevent interspecific competition. = Disturbances act to disrupt stable ecosystems and clear species' habitat. As a result, disturbances lead to species movement into the newly cleared area (secondary succession). Once an area is cleared there is a progressive increase in species richness and competition between species takes place. Once the conditions that create a disturbance are gone, and competition between species in the formerly disturbed area increases, species richness decreases as competitive exclusion increases.

Terrestrial animal diversity generally _____ as latitude increases; marine animal diversity generally ______ as latitude increases.

Terrestrial animal diversity generally decreases as latitude increases; marine animal diversity generally decreases as latitude increases. the biodiversity and latitude trend tends to be rather linear

models of successional change - summary

The facilitation modelis based on the assumption that only particular species with qualities ideal for "early succession" can colonize the newly exposed landforms after an ecological disturbance. These "colonizing" qualities include: highly effective methods of dispersal, the ability to remain dormant for long periods of time, and a rapid growth rate. However, the pioneer species are often subsequently less successful once an area has been heavily populated by surrounding species due to increased shade, litter or concentrated roots in the soil, etc. Thus, the presence of early successional species often changes the environment so that the habitat is less hospitable for the original species' own ecological demands and facilitates the invasion of later-successional species. In the tolerance model, new pioneer species neither inhibit nor facilitate the growth and success of other species. The sequences of succession are thus entirely dependent on life-history characteristics such as the specific amount of energy a species allocates to growth. The climax community is composed of the most "tolerant" species that can co-exist with other species in a more densely populated area. Eventually, dominant species replace or reduce pioneer species abundance through competition. The tolerance model is completely dependent upon life history characteristics. Each species has an equally likely chance to establish itself in the early stages of succession and their establishment results in no environmental changes or impacts on other species. Eventually, early species, typically dominated by r-selected species, which prioritize fast rates of reproduction, are out-competed by K-selected species (species that become more dominant when there is competition for limited resources). In the inhibition model, earlier successional species inhibit growth of later successional species and reduce growth of colonizing species already present. Pioneer species might modify the environment through rapid growth and make the area increasingly shady (essentially increasing competition for light). The environment is thus less hospitable to other potential colonizing species. The only possibility for new growth/colonization in this successional sequence arises when a disturbance leads to dominating species being destroyed, damaged, or removed. This frees up resources and allows for the invasion of other species that were not previously present

Autogenic and allogenic succession

autogenic succession - can be brought by changes in the soil caused by the organisms there. These changes include accumulation of organic matter in litter or humic layer, alteration of soil nutrients, or change in the pH of soil due to the plants growing there. The structure of the plants themselves can also alter the community. For example, when larger species like trees mature, they produce shade on to the developing forest floor that tends to exclude light-requiring species. Shade-tolerant species will invade the area. IN SUMMARY - A type of succession where the plant community changes the environment; changes that occur within a community caused by the actions of the community members allogenic succession -is caused by external environmental influences and not by the vegetation. For example, soil changes due to erosion, leaching or the deposition of silt and clays can alter the nutrient content and water relationships in the ecosystems. Animals also play an important role in allogenic changes as they are pollinators, seed dispersers and herbivores. They can also increase nutrient content of the soil in certain areas, or shift soil about (as termites, ants, and moles do) creating patches in the habitat. This may create regeneration sites that favor certain species. IN SUMMARY - A predictable change that occurs within a community due to activity not related to the activities of the community

frequent, intermediate, and lack of disturbance to a community - how does it affect the biodiversity of the community

frequent disturbance - leads to a community dominated by pioneer and early succession species intermediate disturbances - biodiversity is highest when disturbances occur at an intermediate frequency lack of disturbances - would lead to a community dominated by late-succession species

Which of the following values can be greater at higher trophic levels? A. Number of individuals B. Biomass C. Energy D. A and B only E. A, B, and C

from textbook: The plants (primary producers) of the Silver Springs ecosystem make up a large percentage of the biomass found there. However, the phytoplankton in the English Channel example make up less biomass than the primary consumers, the zooplankton. As with inverted pyramids of numbers, this inverted pyramid is not due to a lack of productivity from the primary producers, but results from the high turnover rate of the phytoplankton. The phytoplankton are consumed rapidly by the primary consumers, thus, minimizing their biomass at any particular point in time. However, phytoplankton reproduce quickly, thus they are able to support the rest of the ecosystem. answer: D. A and B only

if hawks were removed from the community, which of the following direct and indirect effects would occur

if hawks are removed (top predator), then there are much more snakes present (direct), as their predator was just eliminated from the equation. With that being said, more snakes will mean significantly less mice (indirect) present as they are being fed on by the snake. With less mice means more grass (indirect) available foe the rest of the community.

how are late-succession species affected by early colonizers in all three models

in the facilitation model they are positively impacted while in the inhibition model they are negatively impacted and in the tolerance model they are unaffected NOTE: think name corresponds to how later succession species are impacted!

first colonizer of all three succession models

in the facilitation succession model, only pioneer species can establish in the inhibition and tolerance model, any species arriving first can establish

ecosystem

individuals of different species and their abiotic environment abiotic = An abiotic factor is a non-living part of an ecosystem that shapes its environment. In a terrestrial ecosystem, examples might include temperature, light, and water. In a marine ecosystem, abiotic factors would include salinity and ocean currents. Abiotic and biotic factors work together to create a unique ecosystem.

inter vs intraspecific competition

inter = between species; · may occur when individuals of two species share a limiting resource in the same area. intra = within species

A climax community is one that

is relatively stable and long lasting // it is when a steady state or equilibrium is reached climax community persists relatively stably until a disturbance occurs

population vs community

is the group of individuals of the same species while a community is a group of individuals of the same and different species as well

trophic level transfer efficiency (TLTE)

measures the amount of energy that is transferred between trophic levels (production at present trophic level / production at previous trophic level ) x 100

gamma diversity (regional diversity)

number of species in all of the habitats that comprise a large geographic area (i.e. all habitats in the entire watershed for an area)

Inhibition

occurs when a species inhibits colonization by others by.. - monopolizing resources (taking up space, growing leaves tall to block sunlight from seedlings) Note: when an individual dies, these resources it was monopolizing are freed up, SO succession by inhibition often tends from short-lived (fast growing) species to long lived (slow growing) species

Tolerance

occurs when early-successional species neither inhibit nor facilitate later-succession species - species abundances change over time when some species out-compete others - often, random chance of which species arrives first determines what the dominant species will be - late-succession species often just arrived later or grew more slowly than early-succession species

types of community successions

primary succession: the succession that begins new communities and it is uninfluenced by prior communities - often starts from bedrock -not influenced by prior community -severe disturbance (lava, landslide) IN SUMMARY: it is newly exposed or newly formed land that is colonized by living things secondary succession: succession that follows disturbance of pre-existing community - often soil remains that may contain seeds from pre-existing species - less severe disturbance / more common (flood, fire, winds) - influenced by pre-existing community IN SUMMARY: it is the part of an ecosystem that is disturbed and remnants of the previous community remain

why does amount of sunlight matter in ecology

put simply, it greatly affects the trophic levels. If there are high amounts of sunlight available, more primary producers with higher energy can be produced and grow. With higher producer growth comes more food & resource availability to primary consumers. This would mean more primary consumers available and thus more food for secodary consumers etc. NOTE: with each tropic level, there is lots of energy lost!

ecosystem resilience definition

the ability of an ecosystem to resist change and remain unchanged in the face of perturbations and / or the ability to recover a following change

Bioaccumulation/biomagnification

the build up of a substance (usually a toxin) as it passes through a food chain - environmental toxins become more concentrated at higher trophic levels I.E. krill, which are primary producers, contain trace amounts of mercury due to human dumping of trash and litter out into the ocean. Consumers on the other hand have to kill and eat a lot of primary producers due to trophic inefficiency. Though energy transfer is inefficient, the transfer of toxins is rather efficient and thus the more primary producers the consumers eat, the more toxins they are exposed to and ingesting. And thus the higher up the tropic levels, the higher the amount of toxins present in organisms.

the _____ latitudes get the most energy from the Sun. The _____ latitudes get the least. The difference in solar energy received at different latitudes drives atmospheric circulation. Places that get more solar energy have more heat.

the lowest latitudes get the most energy from the Sun. The highest latitudes get the least. The difference in solar energy received at different latitudes drives atmospheric circulation. Places that get more solar energy have more heat. Note: Latitude increases from the equator (0 degrees) to the poles (90 degrees).

ecosystem diversity

the number of different ecosystems on the planet or in a given geographic area Whole ecosystems can disappear even if some of the species might survive by adapting to other ecosystems. The loss of an ecosystem means the loss of interactions between species, the loss of unique features of coadaptation, and the loss of biological productivity that an ecosystem is able to create.

climatic variables in the environment affect biodiversity.. what does this mean for the several species that live in such environments

the species must be able to survive extremes of the environment! - organisms must be able to survive throughout the full range of environmental extremes and if species fail to do so, they will NOT be able to occur in that region on a permanent basis

A team of researchers identify and document the individuals and species of trees they find on different islands in the Galapagos. They compare the species present and absent on the different islands. What type of biodiversity did the research team investigate? a. alpha b, beta c, gamma d. omega

they compare the species present and absent on the different islands therefore it must be beta

When does competition occur?

when organisms attempt to use the same limited ecological resource in the same place at the same time aka THEY OCCUPY THE SAME NICHE = niche overlap!!