Ecology Unit 2 - Terms and Questions

Continuous Population Growth

Consists of constant smooth growth

Discrete population growth

distinct and in separate breeding time intervals

Geometric growth lambda

lambda is involved in a discrete model growth. It is a factor that change the population size each step.

Exponential Growth

continuous model of growth where the population increase at the rate of “r”.

K

K stands for carrying capacity of a population. as population approaches K, the growth will slow down as it reaches the maximum. Instantaneous rate decreases as approaching “k”

How does instantaneous growth rate change with population size?

 Rate at which populations currently grow at a time interval.  dN/dt = rN(1-N/K)

Density independence

factors are environmental influences, do not vary with population size.

Negative Density Dependence

occurs when a population growth declines due to population increase/concentration.

Positive Density Increase

dependence occurs when a population has increased fitness with a higher population.

 Allee effect

where a small population may have trouble finding mates or resources.

Life history traits

Traits of an organisms life cycle, including reproductive age, number of offspring, and lifespan

Trade-offs in the allocation of resources provide a basis for understanding life
histories.

Organisms face trade-offs in how they allocate their limited resources to various life history traits, such as growth, reproduction and survival.

what is R in relation to life history

high reproduction rates

what is K in relation to life history

survival and competitive ability is favored over fast reproduction

Trinidadian guppies examples

n.a

resource definition from the perspective of competition

Competition occurs when two or more individuals have a need for the same, limited resource, like food or space

realized niche

portion of the fundamental niche that the species actually occupies due to competition and other factors.

fundamental niche

represents the full range of environmental conditions where the species could POTENTIALLY survive if it could survive and reproduce

intraspecific competition

competition among organisms in the same species

interspecific competition

competition where organisms compete with different species

Competitive exclusion principle

Two species with similar niches cannot coexist in the same habitat for an extended period of time. One will outcompete the other for resources and fitness.

The role of abiotic factors on the outcome of competition

The role of disturbances on the outcome of competition

Shade tolerant plants compete with Longleaf pine in their natural habitat, but fires help control and shape ecological diversity.

The role of predation and herbivory on the outcome of competition (example of toads

Predation and herbivory can influence the outcome of competition between species. Predators that favor one over the other create asymmetry in the environment due to uneven predation.

Exploitative competition = resource competition = indirect competition

Occurs when species compete for limited resources like food or habitat. Reducing the others ability to survive

Interference competition = direct competition

Interference with the access of competitors to resources. This can involve aggressive behaviors, territorial disputes, and direct interactions that hinder the ability of a competitor to access resources

Allelopathy

biological phenomenon where one plant species releases chemicals into the environment that inhibit growth or development of a nearby species. Interference competition.

Preemption vs Territoriality

Apparent competition

refers to a situation where two or more species compete due to shared influence of a common predator or herbivore. Indirect form of competition that occurs when the presence of one species affects the abundance or success of another species through shared predation or herbivory

Ectoparasites

live on the exterior of the host. Easier access to resources but more exposed to environmental conditions. Risk of grooming or immune responses

Endoparasites

live on the interior of the host. Relatively stable environment but most avoid the immune system.

Bacteria vs Protozoans

Bacteria – antibiotics for bacterial infections

Protozoans – antiparasitic dugs for protozoan infections

what are some common plant defenses against herbivory?

Plant defenses can include, chemical toxin release, mechanical defenses such as thorns, nutritional manipulative levels, and tolerance to withstand damage and regrow.

What are some Animal defenses

Animal defenses can include, poisons release, physical armor or shells, aposematism like warning coloration, behavioral alarm signaling, or structural like antlers or horns.

What is Batesian mimicry

harmless species resembles the appearance of one with toxic or dangerous chemicals to gain protection.

Mullerian Mimicry

multiple species share the same coloration to create a warning sign for predators to increase all of their individual fitness

Why does the growth of the predator population lag behind that of the prey
population?

Predators reproduce at a lower rate than prey does. Prey have shorter generations so they can increase quickly, but it takes time for the predator to do so. Creating a lag in the populations.

Stochastic Model

include uncertainty into the system being studied

Deterministic

creates a predictable and certain model. Model wull produce the same output each time.

Ecology of fear

concept that refers to the presence or perception of predators in an ecosystem can have far reaching effects on the behavior/distribution and interactions of prey species. Prey will alter behavior.

Red Queen hypothesis

Maintenance of sexual reproduction in organisms. Organisms that sexually reproduce have a greater advantage to those who asexually reproduce. Less challenging for these species to develop strategies and to evolve to better fit their environment.

 why is sexual reproduction considered more costly than asexual reproduction?

Sexual reproduction takes longer to accomplish, requires usually two individuals of the same species, and nurturing from one of the parents.

What is Recombination

the process by which DNA strands are broken and repaired, producing new combinations of alleles, occurs in nearly all multicellular organisms and has important implications for many evolutionary processes

Mutualistic Coevolution

both part benefit

Antagonistic Coevolution

one acts in a detrimental way to the other

Co-evolutionary

– leads to specialization. Host-parasite interactions result in highly specialized parasites that evolve to exploit host species.

Parasite Load

Number of quantity of parasites present in a host organism. Measure of intensity of parasitic infection and increases diseases severity.

Symbiosis

living together: intimate association between two organisms. Every species has at least one symbiotic association

Mutualism

Vertical transmission

refers to the transmission of pathogens from one generation to the net, from parent to offspring

Horizontal transmission

pathogens move around the same generation, through direct contact or environmental exposure

Symbiosis

Commensalism

one species benefits and the other is neither helped nor harmed

Mutualism

Both species will benefit from the reaction

Symbiont

term used to describe an organism participating in a symbiotic relationship regardless if affected or of what kind.

endosymbiosis

a symbiotic relationship where one partner lives inside of the other

Sexual reproduction is considered more costly than asexual (=clonal) reproduction because (in general):

Select all that apply

Mating behaviors may increase the risk of herbivory, predation, and parasitism

Mating behaviors require time and energy

Sexual organs require energy and resources.

Symbiosis can include which of the following? Select all that apply

intimate interactions between two species that are beneficial to one partner and detrimental to the other

mutually beneficial intimate interactions between two different species

intimate interactions between two species where one species obtains a benefit and the other is unaffected

Which of the following three interactions is/are mutualism/s?

Ants and acacias: Acacia plants develop hollow thorns that provide shelter for ant colonies and produce nectar on their leaves (in structures called nectaries) that provide food for ants. The ants defend the acacia plant from herbivores.

Fig and fig wasp: The adult wasps crawl into the cluster of fig flowers to lay eggs. By moving around, the adult wasp pollinates the fig flowers, allowing them to produce fruit and seeds. As the fig fruit develops, it provides shelter for the wasp larvae.

What is a generalist example in mosquitos?

Mosquitos wouldn’t be adapted to only go for one kind of bird, they would pick any available bird for food.

true or false: Because most ectotherms maintain a nearly constant body temperature, they are relatively unaffected by small changes in environmental temperature

False

what would a graphic example of volcanic emissions?

short burst in temperature followed by a spiked decline

what would be a graphic example of anthropogenic aerosols?

almost a linearly negative graph

what would be a graphic example of greenhouse gases?

the graph would be going up exponentially overtime.

How do you calculate the anomaly for the average temperature?

subtract the new temperature from the old.
EX: 1971 was 96 F , 2019 was 98 F.
so, the anomaly would be 2

what is the best explanation for the glacial and interglacial periods?

Changes in the Earth’s Orbit.

which statements are true?

Mean global sea level has risen over the past 130 years

Arctic sea ice area tracked since ~1980 exhibits a decreasing trend

Mean global surface temperatures have increased, on average, over the past 150 years

Mean atmospheric CO2 concentrations have increased since 1960 (measured in Hawaii)

statements that are true about greenhouse gases and effect?

The greenhouse effect is caused by multiple greenhouse gases, including carbon dioxide, water, and methane

Most greenhouse gases are transparent to shortwave solar radiation, but absorb longwave thermal radiation

The greenhouse effect may cause energy to be transferred back and forth between the Earth’s surface and the atmosphere multiple times before escaping into space

True or False: above 4 C water volume increases at its temperature increases. This had contributed to rising sea levels

True. Volume will increase as water temperature increases for a bit.

true or false? Temperature reconstructions for the Northern hemisphere based on tree rings support that the hypothesis that the last 30 years have been cooler than any 30-year period in the last 800 years.

false. temperature has increased.

The Lotka-Volterra model has several unrealistic assumptions.  Which of these is an assumption of Lotka-Volterra?

Predators never become satiated. in other words, predator can consume infinite amount of prey

prey grow exponentially in the absence of predators

The non-venomous scarlet king snake (Lampropeltis elapsoides) found in the eastern United States has similar coloration to that of the venomous eastern coral snake (Micrurus fulvius). The strategy of the scarlet king snake is an example of

Bayesian Mimicry; it is pretending to play hazardous to increase its survival.

True or False: Batesian mimicry is an honest signal

False.

The realized niche describes

The set of environmental conditions in which the species is actually found in nature.

Because of its relationship with its host, the ectoparasite generally has…

low exposure to the host’s immune system.

If search efficiency (i.e. attack rate) increased, but all else stayed the same, what would happen to prey population growth rate (dN/dt)?

Decrease

If hares moved faster and were thus harder for lynx to capture, which rate in the Lotka-Volterra predator-prey model would change?

searching efficiency (a)

Suppose you are studying coyotes and wolves, and you determine that wolves are experiencing a reduction in their population that can be attributed to a contagious pathogen that the coyotes carry, but that it is more harmful in wolves. Suppose also that there are an excess of prey items for coyotes and wolves. The observed reduction in the population of wolves is an example of:

apparent competition

Some species of bees imitate the coloration of wasps, and vice versa; their coloration and patterns are very conspicuous. Both can sting predators.  These bees practice (or use):

Chemical Defense , mullein mimicry

When one competitor exploits a resource more efficiently and the other competitor is better at tolerating stressful conditions or avoiding consumers, such that the two competing species coexist locally in different microhabitats, this phenomenon is known as __________ competition.

asymmetric

Because of its relationship with its host, the ectoparasite generally has _____

low exposure to the host’s immune system.

Assuming that resources remain unlimited for the prey population, what will happen if the prey consumption term (a N_predator N_prey) is removed from the Lotka-Volterra prey equation?

exponential growth of prey

As populations of predators grow, their resources (prey) become scarcer.  Thus, from the perspective of the predator population, the availability of resources (prey) is:

density dependent (= dependent on the density of the predator )

Suppose that a population of rabbits and a population of hares live in the same area, but they eat completely different diets and don't compete over space.  A sudden increase in the population of rabbits occurs, which attracts more individuals of coyotes (suppose the rabbits just smell very tasty to the coyotes, but that a certain density of rabbits is needed before the coyotes are attracted to the area).  However, the coyotes are better at catching the hares than the rabbits (suppose rabbits are just faster and/or they have better hiding places).  This results in a decrease in the population of hares, but not in a decrease in the population of rabbits.  The decrease in the population of hares is best described as a result of:

asymmetric competition

when is the population growth the fastest?

when it reaches half of its carrying capacity

in the Allee effect, fitness increases when what increases?

population density. benefits species when helping find mates.

What is Age structure?

the distribution of individuals among age classes within a population

Fecundity

number of offspring produced by an organism per reproductive episode

Parity

the number of reproductive episodes an organism will experience

Parental investment

the time and energy given to an off spring from its parents

Longevity

the life span of an organism

principle of allocation

observation that when resources are devoted to one body structure, physiological function or behavior they cannot be allotted to another.

as the number of offspring increases…

the amount of parental care offspring will decrease

what is the effect of offspring on parents

stimulate parents to Hunt harder for food to feed their offspring. affects a parents fitness too

R-selected organisms will usually…

mature rapidly at an early age
short lifespans
large number of offspring
high mortality rate

K- selected organisms will…

Mature slowly
longer life span
few off spring at a time
high parental investment

Tobacco nicotine plant example of Cost of Defense

Lion example of Consumer Conversion rate

a lion will have a Higher conversion rate when it eats a deer compared to a rabbit.
consuming 2 prey to produce 1 baby
b=1/2 (larger b is more efficient production)

In the Lotka Volterra equation the term ab N prey N predator describes:

the rate at which new predators are added to the predator population