Ecology Flashcards
What is the law of minimum? Who suggested it
Justus Liebig The distribution of a species will be controlled by that environmental factor for which it has the narrowest range of tolerance.
What is the law of tolerance and who suggested it?
Find out
what is population ecology?
population ecology includes understanding, explaining, and predicting species distributions. Why do species inhabit particular areas, and how are they prevented from establishing beyond their range limits? Such range questions have become popular in the last decade or so in response to concerns about climate change.
what is interspecific competition?
individuals of different species compete for the same resource in an ecosystem (e.g. food or living space).
what is amensalism?
when one species is destroyed or negatively affected and the other species is unaffected either way (not positively or negatively)
e.g. cattle trampling over grass
what is intraspecific competition?
happens between individuals of the same species.
what is mutualism
both species benefit from their relationship but neither are dependant on the other
what is a + + relationship?
mutualism and symbiosis
what is a + - relationship?
predation, paratisism and herbivory
what is a + 0 relationship?
commensalism
what is a - - relationship?
interspecific and intraspecific competition
competition,
Synnecrosis
what is a 0 - relationship?
Ammensalism
what is a 0 0 relationship
neutrality
what are the three types of herbivory?
•1. Classic herbivory
–One animal eats parts of several plants e.g. cow & grass
•2. Predator type
–One animals eats and kills several plants e.g. birds & seeds
•3. Parasitic type
–One animal eats part of one plant e.g. aphids on a rose,
–Or fungal disease on plant.
give an example of herbivoury that is + +
bees - the bees get nectar and the plants get cross pollenation
what are Granivores
eat seeds
what are Browsers
woody material
what do browsers lack the enzymes to digest?
lack enzymes to digest cellulose even though their diet is high in cellulose (so they need to eat excessive amounts to get enough nutrition)
in ruminants:
what processes occur in the rumen and reticulum?
Anaerobic bacteria and protozoa, fermentation vat, pH regulated
Regurgitated Cud Methane.
in ruminants:
what processes happen in the
•Omasum
•Abomasum (true stomach)
final digestion including micro organisms
in plants what is the protein content greatest in? and why do herbivores give birth at this time of year
growth, leaves, buds, flowers etc. so herbivores give birth in spring to get the richest nutrients possible for better growth
what are the 4 types of plant defence and give examples
physical: spines (cactus)
chemical: Often secondary products of plant metabolism, Some act directly on herbivore
Some act indirectly eg by attracting organisms to protect the plant.
Masting: producing too many seeds so that animals (squirrels) can feed on them and a lot of seeds will still make it through and germinate becoming future trees
Symbiosis: ants live on the tree, tree gives then nooks for homes and ants protect tree from grazing herbivores by attacking their faces when trying to feed
what is commensalism
one organism benefits from the other without affecting it
e.g. clownfish live in stinging sea anemones and are protected by the stingers but dont give the anemone anything in return
give two examples of plant defence chemicals
•Cyanogenic Glycosides:- Toxins stored as inactive conjugates kept separate from activating hydrolases.- vacuole
•HCN released from cyanogenic glycosides present in more than 2,500 plant species.
•
what is Azadirachin
a complex limonoid, most powerful deterrent to insect feeding.
Effective at 50 parts per billion.
what are the pros and cons of herbivoury over detrivory
–Pros
•Better quality
•More digestible than dead leaves
–Cons
•More poisons and defences
•Less plentiful
•Often only seasonably available
Why is damage to natural populations of plants limited and extinctions rare?
- Animals will eat the easier targets
- Allows others to grow
- Population usually not limited by the number of seeds produced
- Prey switching
- Herbivores eaten
what is Optimal range
species normally only functions best over a limited/specific part of the gradient
what is this
law of tolerance
why do species not exist over the entire range of tolerance?
because of comepetition from other competitors -
•competition – other species may be better suited to conditions at a site and will therefore outcompete other species.
Environmental gradient tolerance can..
set the potential range of a species
competition can set the
observed range of the species
what are the three images called?
what are the vertical and horizontal axis called
a. bioindicators
b. rare
c. ubiquitous
vertical: fitness/abundance
horizontal: environmental gradiant
give some examples of temperature based abiotic factors
temperature:
•Important because of its effect on biological processes and the inability of most species to regulate body temperature.
•
•Rate of shell formation in corals increases with temperature and is supressed by low temperatures.
but plants are exceptionally susceptible as cells rupture if they freeze and must find alternative methods of storing water
other plants can survive freezing over ONE night (cactus)
name these 4 types of estuaries
a. vertically mixed
b. slightly stratified
c. highly stratified
d. salt wedge
why is salinity an important abiotic factor?
•Important in both terrestrial and aquatic environments – high and low concentrations control the affect osmotic resistance and impact water uptake or loss.
what percentage of protoplasm is water and why is it an important abiotic factor?
Protoplasm is 85-90% water and without available moisture there can be no life
what does water affect?
distribution and abundance
what depth does ir (infraed) and UV (ultraviolet) penetrate
2 metres depth
green and blue light penetrate deepest
Primary production confined to
euphotic zone
(photosynthesis and most animal life)
light still penetrates into
dysphotic zone
no light reaches the
aphotic zone
what is compensation depth
The point at which gains from Photosynthesis in plants equals losses due to respiration
label these zones
A: net productivity
B: gross productivity
C:compensation depth
D: respiration rate
E: bottom of euphotic zone
label the levels in this marine habitat
a. supratidal zone
b. littorina or upper intertidal zone (highest tide falls here)
c. middle intertidal zone
d. lower intertidal zone (lowest tide falls here)
e. subtidal zone
What is endosymbiosis
when one animal lives within anothers body
what is ecotsymbiosis?
lives on the body surface of the host, including internal surfaces such as the lining of the digestive tube and the ducts of glands.
what is Synnecrosis
interaction is so mutually detrimental that it results in death, as in the case of some parasitic relationships
what is the most common type of interspecific competition
neutralism
what is a ubiquitous species?
found everywhere therefore it has a large environmental gradient
what does the red and green line show?
red line: fundamental niche, full range of environmental conditions and resources an organism can possibly occupy and use, especially when limiting factors are absent in its habitat.
green line: realised niche (the niche in which it can survive)
why does net productivity lower near the water surface
too much light because plants are adapted for certain amounts of photosynthesis hence lower abundance
what is the biosphere?
thin layer around the earth which contains life
it contains the hydrosphere and atmosphere in which most species live
top of lithosphere and consists of ecosystems
which part of this is the fundamental niche?
which part is the realised niche?
where do other species fit that are more adapted to other parts of the environment?
Hutchinson created this concept
blue arrow: entire box is the fundamental niche
orange arrow: middle of the box where RG3 passes through is the realised niche
green arrow: the edges of the box are where competing species that are more adapted to that area than the niche species in the middle of the box
label the red area and the blue area
red: fundamental niche
blue: realised niche
what is batisian mimicry
A type of mimicry in which a harmless or palatable species resembles a dangerous or poisonous species
what is asymmetric competition?
•Benefit to one species and a cost to the other.
+/- relationship
direct competition between two entities that are not necessarily utilizing the same type of food etc resources or approach in order to achieve a similar result.
what is the Tens Rule?
establishment in a new area is difficult, most species that are potentially invasive do not suceed, only 10% of species that arrive in a new area will establish and only 10% of those will become a problem species.
what is autecology
study of a single species
what is synecology?
study of a group of species
what is an ecological engineer?
beavers and humans
a species that modifies its habitat to make it more suited to their needs
e.g. beavers build dams, humans build houses
what is Gauses Principle?
it can be broken under certain conditions
no two species can coexist indefinately in the same ecological niche with limiting resources
competitive interaction means that the resource (food,space etc) becomes limited and one species outcompetes the other
what is a keystone species?
A species that has an exceptionally great impact on the other species in its ecosystem relative to its abundance.
e.g. a species that eats both competing species so their populations stay low and dont get to the point where they are competing for food/habitat space (e.g. lion eating zebras and antelope)
what was Gauses experiment?
he demonstrated that Paramecium aurealia outcompeted paramecium caudatum
what habitats are two dimensional?
what are three dimensional?
tundra and deserts
rainforests
what are ecological equivalents?
what do they demonstrate?
e.g. penguin and Auk, they looks similar but have evolved individually due to similar environments
•Demonstrates that energetic relationships have an important influence on niches and the species that occupy them.
what is convergent evolution?
convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.
what are the methods of dispersal?
diffusion: gradual movement of a population across hospitable terrain over several generations
Jump dispersal: movement of individuals across large distances followed by establishments to form a new population
secular dispersal: diffusion taking place in evolutionar timescales - natural selection causes migrants to diverge from the ancestral type
what is Reids Paradox?
extremes of dispersal lead to species reaching new areas quickly
name some dispersal barriers
waterfalls (fish cannot swim up them and difficult for terrestrial animals to cross)
what is ideal despotic distribution?
density of animals can be highest in the most unsuitable habitats
what is K in population ecology?
K = Capacity
what are the two types of life table?
stage specific: often used where clear stages are identifiable in the life cycle e.g. cub, sub adult, adult or egg, crawler, insta, 2nd insta, 3rd insta, 4th insta, adult
or
age specific: this is most common, these are better for longer lived species where you identify the ages of individuals
what does dx mean in population ecology?
how do you calculate it?
dx = number that are dying
nx - nx+1 = dx
number alive = nx and number alive in the next age class = nx+1
so number alive - number alive in the next age class + 1 = number dying
so is there were 1000 in age class 0-1 and 801 in age class 1-2 1000-801=199 dying
what is community ecology?
multiple populations interacting with each other e.g. prey and predators
name the organisational levels in ecology
highest to lowest (complexity)
biosphere
ecosystem
community
population
organism
lowest to highest (predictability)
biosphere
ecosystem
community
population
organism
what is population ecology
concerned with species abundance in nature, the growth/declines of populations
what is ecosystems ecology?
concerned with the flow of energy and nutrients through communities and the effect it has
what is the n - dimensional hyper volume?
it relies on law of tolerance
species tend not to exist over the entire range of environmental tolerance because another species will find that low tolerance to be their optimum range and will outcompete the first species
who wrote the essay n principle of evolution?
Thomas malthus, he Claimed: population was increasing faster than food production. He feared eventual global starvation.
label this graph
point of crisis and carrying capacity
red arrow: population crisis ( too many animals not enough food
green arrow: carrying capacity: just enough food to maintain animal numbers
what does k selection mean
K-selection referred to selection for competitive ability in crowded populations
what does r selection mean?
r-selection meant selection for high population growth in un-crowded populations
what is the exponential growth equation
dN
—— = r N
dt
so dn / dt = r N
change in number = dn, change in time = dt, rmax = rate of increase N = population size
logistic equation of population growth
dN (K – N)
—— = r N ———
dt K
n= population
k = carrying capacity
dN = change in number, dT = change in time
what is a sigmoid growth curve?
stabilised by availiable resources
what is exponential growth?
the rate of change increases over time
which line on the graph is for which equation?
which part of the line is r dominated and which is k dominated
•The exponential growth equation (dN/dt = rN) assumes that the population growth rate (r) is constant.•Not realistic over long periods of time.•We assume instead that r declines as N increases.
what are the characteristics of an r selected species
•The potential for a species to multiply rapidly – producing large numbers of progeny - early in their life cycle – may be advantageous.
•
•Particularly in environments that are short-lived.
•
•Allows organisms to colonize new habitats quickly, and exploit new resources.
•
•Characteristic of organisms that invade disturbed land – e.g. many annual plants
many and small reproduction e.g. rats
what are the characteristics of a k selected species?
•Their populations are usually crowded.
•
•Those that win in a struggle for existence do so because they have grown faster (rather than reproducing).
•
•Or have spent more of their resources in aggression or some other activity that has favoured them in competition with others.
Or few large progeny
which graph is k selected and which is r selected
type 1 = K selected
type 2 = mixed
type 3= r selected
which lines on this graph are r and k selected?
type 1 = k selected species = green arrow
type 2 = mixed = red arrow
type 3 = r selected = blue arrow
what type of environment do r selected species live in?
unstable
•Density independent control of population size
what type of environment do k selected species live in?
•Characteristic of stable environments
•
•Density dependent interactions
•
•Control of population size
how do you work out mortality rate?
qx = dx / nx
so qx = mortality rate, dx = number dyiing, nx= number alive
could intraspecific competition decrease the size of the overlap?
no! intraspecific competition will be working against it and increasing the overlap
where is the zone of overlap/character displacement
what is character displacement?
An outcome of competition in which two species living in the same area have evolved differences in morphology or other characteristicsthat lessen competition for food resources.
what are the following two types of competition?
exploitation competition:
•Occurs when individuals use the same limiting resource or resources, thus depleting the amount available to others. Exploitation competition may cause the exclusion of one species but doesnt always result in extinction.
Interferance competition:
Occurs when individuals interfere with the foraging, survival or reproduction of others, or directly prevent their physical establishment in a portion of the habitat.
who was Thomas Park
• showed that via interference competition the Confused Flour Beetle and the Red Flour Beetle could not coexist in simple environments.
•
•One species always excluded the other.
•
•Unless there was a refuge.
what are the Lotka – Volterra Competition Equations
what is the equation for potential mortality factor?
•K = logNt - logNt+1
Nt = density of population before the mortality factor
Nt+1 = the density of the population after the mortality factor
what is a metapopulation?
series of small separate populations that mutually affect one another.
what are key factors?
Mortalities that move populations away form equilibrium (or mean levels)
what are density dependent factors?
•Factors that return populations for equilibrium are called density dependent
how do you calculate distance moved
Dn√(〖log〗_e R_(0 ) )
–Where D average dispersal distance
–n = number of generations
–R0 = net reproductive rate
•When we plot the predicted number of species on the planet using species area curve we get less species that are predicted to exist…why?
•It is because barriers allow secular dispersal and speciation to occur, allowing a wider range of species to exist. The more that humans break the barriers down, the more species will disappear.
what is ideal despotic distribution
•density of animals can be highest in the most unsuitable habitats.
what is mutualism sometimes known as?
what is symbiosis sometimes known as
facultive (non obligatory) relationship
obligatory but can sometimes be faculative
what is a reservoir host?
•Reservoir hosts are vertebrates that host an infection while it is not infecting humans.•Reservoir hosts are used by the disease as a source of maintenance.
•
•A single reservoir host maybe be re-infected several times.
what is brood parasitism
cuckoos
a species which uses a host species to raise their eggs
what is kleptoparasitism
•Kleptoparasitism (literally, parasitism by theft) is a form of feeding where the parasite steals food that the host has caught, killed, or otherwise prepared.
•
•The kleptoparasite gains either by obtaining prey that it could not obtain itself, or by saving the time and effort required to obtain the prey.
e.g. birds harassing gulls for fish theyd just caught till they dropped it
how do you find the frequency when recording using quadrats?
•(P/N) x 100 (%)
p = number of quadrat sections with species present
N = total number of quadrats
so species present / total number of squares x 100 = frequency (in percentage)
how do you calculate cover percentage when recording in the field?
(A/N) x 100 = % Cover
Pin frames - count number of pins (A)
touching a species out of total number (N) of pins
how do you calculate the average number alive during the age class?
age class = LX
LX = ((nx + nx+1) / 2)
so its just a mean of the number alive
so LX = ((number alive + number alive in next population) / 2)
how do you calculate tx?
tx = stage that is required to calculate the life expectancy/ sum of the average number alive in age class
why is life expectancy lower in the first year
in the first year animals dont know the habitat too well, accidents and predators etc, so life expectancy goes up in the next year as they get to know the area and then it slowly declines again in further years as normal
how do you calculate the fercundity?
fercundity = female offspring = mx
fx / nx = mx
fx = total young, nx = number alive, mx = fercundity
so total young / number alive = fercundity
how do you calculate pattern of fercundity?
LX x mx = pattern of fercundity
so LX = average number alive during the age class
mx = fercundity
how do you work out total fercundity?
Ro= net reproductive rate
ix x mx = Ro
how do you calculate population growth?
Nt+1 = Ro x Nt
Nt+1 = population size at the next generation
at an Ro of 1 the population is stable so every 1 female lion produces 1 female offspring
at an Ro of 2 the population doubles so every 1 female lion produces 2 female offspring
mainly useful for populations that breed once a year
how do you calculate population growth for species that reproduce more than once per year?
dN / dT = rN =(b-d)N
N = population, r = growth rate, b = birth rate, d= death rate, dn = change in number, dt = change in time
e.g.
so r = 0.1 + N = 100
dn/dt = 0.1 x 1000 = 100
so 100 individuals are added to the population per time interval
how do you calculate carrying capacity?
dN / dT = rN (K - N) / K)
dN/ dt = rate of population change, rN is the percaptia growth rate, N = population size, K = carrying capacity
so is K is 1000, N = 500+ r = 0.1
dn/dt = r x N ((k-N) / k))
dn/dt=0.1x(500(1000-500) /1000))
dn/dt=0.1 x (500 x 0.5)
dn/dt = 25
