BIOL251 Exam Flashcards
Example exam Q:
Draw a conceptual diagram to illustrate how a temporal
correlation between increased abundance of deer and
decreased abundance of caribou may be mediated by
several different types of ecological interactions.
TBC
Exam Q:
Describe the flow of nutrients through an ecosystem,
indicating where there might be limitations and what
factor(s) are involved in these limitations
TBC
What are the four biological disciplines?
- evolution - natural selection
- physiology - environmental tolerance & metabolism
- behavioural - dispersal & territoriality
- Genetics - adaptations
Describe an experiment analysing the complex patterns and processes (interactions) of ecology.
Frog deformities case study:
Testing if pesticides or parasites caused deformities in frogs.
6 ponds with deformed frogs:
- tadpoles placed in mesh cages, some ponds has pesticide absent and some present.
- split in 2, large mesh allowed parasite to pass through
- small mesh prevented parasite
Results: Small mesh with presence and absence of pesticide posed same results: no deformities
Large mesh with both presence and absence of pesticides had deformities, but highest deformity % was with pesticides.
Variables to consider:
1. Nitrogen from fertilisers provides algae blooms and more nutrients for snails (parasite host)
2. pesticides weakens frogs resistance to parasite
3. Climate change and increased UV makes them less resistant
4. When infected as a tadpole, they die before metamorphosis
5. deformities in frogs makes them more susceptible to predators
What is evolution?
Change over generations within a population
Properties of a population is not from anticipation of the future, instead the result of past evolutionary change,.
What are some requirements for natural selection?
- Inheritence
- Variation
- Relative fitness (offspring)
- Reproduction (intra and intersexual selection)
- Fitness
What are some evolutionary Constraints?
temperature
natural disasters
extinction
What are some modes of evolution that are non-adaptive?
- Genetic Drift
–> gene freq. in a small population can change dramatically via
a) Bottlenecking (natural disaster)
b) founder (isolation - darwins finches)
c) Fragmented habitat ( geographic barriers) - mutations
- how variations arise - Geneflow
- counteract effects of natural selection
- transfer of genes from one population to another - non-random mating
- sexual selection
Distribution and Abundance:
Describe Rapoport’s rule and and suggested hypotheses.
Definition:
describes why geographic distribution differs between high and low altitude for mammal species. This hypothesis considers how environmental variability (climate, glaciation and lack of competition) can impact species richness across latitudes.
Polar species have larger geographic ranges than tropical species.
Environmental variability rises with increasing latitude as it provides more ecological opportunities and broader variations in habitat for species.
→high seasonal variation
→decreased competition
→various adaptations leads to higher rates of speciation
Low latitudes: species experience more stable environmental conditions, resulting in smaller ecological niches and geographic range.
→less seasonal variation
→increased competition
→species become more specialised
Hypothesis: Climate variability, glaciation, lack of competition.
Species thermal tolerance
Mammals generally only found in poles.
Define, and in examples (real and hypothetical), distinguish between the fundamental niche and the
realised niche
Fundamental Niche: ideal, Ecological space occupied by a species in absence of competition and other interactions with species.
Hypothetical Fundamental
Bird species can tolerate range of temperatures, eat range of foods, and nest anywhere
Hypothetical
Coyote species can survive in forests to deserts.
Realised Niche: Realistic environment, a species can only use limited resources of an area because of interactions with other species
Real Bird:
Can only nest in one species of tree due to competition
Real Coyote
Competition with other carnivores and humans, results in a much narrower habitat range
Describe Hanski’s Rule (1982) and reasoning of Distribution and Abundance:
Describes the positive correlation between distribution and species abundance
Species with wider distributions are more abundant.
Reasoning:
Sampling issues - over a wide scale its hard to not recount individuals
Generalist species: eats anything tends to be more distributed than species who are ‘picky’ with their resources - narrow range
what are the main drivers of distribution?
Abiotic: Light, temp, oxygen
Biotic: Compeition, predation, disease
Behaviour: habitat selection and dispersal
Disturbance: Natural or human cased
What are the limitations of rapoports rule?
Does not consider all species (only mammals)
Does not consider elevations
Explain Acclimatisation versus Acclimation versus adaptation
Acclimation:
reversible physiological or behavioral response of an individual organism to short temporal
changes in its environment
ie: temperature alone
Acclimatisation
similar, but old and new environment differ in many ways
(Winter and Summer)
**Both are a form of phenotypic plasticity
Adaptation: changes in a population over time in response to environmental pressures.
Both Adaptation and Acclimation are essential for organisms to respond and persist in their environments,
How would you test acclimation?
Lab experiment: over short period
- individuals breed in different conditions
- Transgenerational acclimation: how parental tolerance affects offspring.
- measure thermal tolerances: raising them in similar conditions
- if temperature curves are maintained, it is a fixed trait
Provide an example of acclimation (temperature):
Black rock cod:
Enzymes denature >5 degrees
Developed lack of RBCs since metabolism is so slow, their bloodstream can carry oxygen on its own since oxygen concentrations in cold water are so high
What are some moisture adaptations?
Waxy cuticles - plants
Frogs can apply muscous layer in a burrow to avoid dessication when ponds dry up (mains frog)
- mass breeding events
Lizards developed rough skin and scales
Get water from mist and water droplets on skin and consuming insects.
Describe an interaction of abiotic factors (light, temp and moisture on a species)
Western Hemlock (tree)
Very water hungry - short roots, loose water rapidly
Needs to be in high humidity environments
Describe adaptations to changes in light, moisture, and temp
Photosynthetic pathways (C3, C4, CAM)
CAM plants open stoma at night to avoid dessication
- adapted to live in arid/semi arid locations
Can photosynthesis without opening stoma during the day as they store CO2 at night.
What are some examples of physical and chemical interactions?
- soil resources and texture
- salinity, acidity, oxygen
Mudskippers:
Semi-Terrestrial
Air pockets functioning like lungs.
describe the intercation between Light Temperature and pressure
going deeper affects physiology to live
Wider thermal tolerances of species, diving deep underwater changes temperature, must be able to withstand intense pressure
Describe a dispersal concept
Reids Paradox
the observed large discrepancy between the rapid rate of
movement of trees recolonizing areas at the end of the Ice Age and the
observed slow dispersal rate of tree
seeds spreading by diffusion
Worded differently:
Reids paradox describes that rare seed disperal events (found densely in unlikely locations) must have been facilitated by varying biotic (mostly birds) and abiotic (wind) vectors.
Define dispersal and describe some advantages and limitations
Dispersal:
Spread of species geographically
Jump dispersal (human induced)
Limitations:
- competition
- abiotic conditions
- predation
- realised niche
- geographic barriers
- life cycle and reproductive restrictions
Adaptations
- fly
- float
- hitch a ride
- vectors
How are dispersal ranges tested?
transplant experiments
Habitat selection model: Describe an Ideal Free distribution
Definition:
a theoretical
spatial spread of members of a population in which individuals take
up areas with equal amounts of resources in relation to their needs, so
all individuals do equally well
As a population fills up the best habitat, it reaches a point where the
suitability of the intermediate habitat is equal to that in
habitat A, so individuals will now enter both habitats A
and B. As these two habitats fill even more, the poor
habitat finally has a suitability equal to that of habitats
A and B.
What is the opposite Habitat selection model of ideal free distribution?
DESPOTIC DISTRIBUTION
Dependent on aggressiveness and dominance in the animal kingdom.
Animal movement is limited by territorial behaviour.
a theoretical spatial spread of members of a
population in which the competitive dominant “aggressive” individuals take up the best resources or
territories, and less competitive individuals take up areas or resources
in direct relationship to their dominance status.
What are some interactions that also limit distributions?
Competition -/-
Allelopathy -/-
(toxin secretions from plants and fungus can limit local distribution )
Predtation and Herbivory (+/-)
Mutualism and Commensalism
Symbiosis: close relationship between two species
Mutualism +/+ (pollination and seed dispersal)
Commensalism is 0/+ (tree hollows as shelter for animals)
Disease and Parasitism (+/-)
(mosquitos and ticks feeding on animals)
Predation and Herbivory +/-
Four criteria when testing if they can limit distribution of prey:
- Prey will survive transplant if protected from predator
- The distribution of predators/prey are inversely related
- The predator can kill the prey, both in field and lab
- Transplantation experiments show the predator is responsible for the killing of prey
Limited predator distribution by limited prey
The four population parameters that change density
- natality (egg, seed, or spore
production; births) - mortality (deaths)
- Immigration: The movement of individuals into an area
occupied by the population. - Emigration: The movement of individuals out of an area
occupied by the population, typically the site of birth or
hatching
Describe how predators and prey co-evolve (e.g, traits that respond to predation and counter adaptations)
Prey; avoid detection, ward off attack, warning colouration, group living, fighting back, escaping when caught, eyes on sides of head
Predators; avoid/increase detection, capture tools or lures, behaviour strategies, ambush vs stalk -group living (e.g. lions/wolves), binocular vision
What other factors affect prey density/abundance (other than Lotka-Volterra)
- Functional
Response of an average predator to prey abundance - Numerical
Response of a predator population to a change in prey density
Prey density: changes in environmental conditions: Amount of shelter for prey / natural hazards (fires) exposing prey
List and describe the factors/variables included in the Lotka-Volterra model that affect predator-prey dynamics.
Prey Increase at intrinsic growth factor ‘r’
PREY REDUCED BY PREDATORS DEPENDING ON
1. predator prey encounters increases with density/abundance of predators (P) and Prey (N)
2. predator search-attack efficiency (a*)
PREDATORS INCREASED BY
1. aPN (encounter rate)
2. efficiency converting prey to offspring (f*)
PREDATORS REDUCED BY
mortality rate (q)
What is the growth rate (r) formula?
growth rate (r) =
(Births-Deaths)/N
(-)ve r = geometric decay
(+)ve = Exponential
Factors influencing growth rate:
1. density dependent(limiting resources, reaching carrying capacity K)
2. density independent (chance)
define the Key variables of Lotka-Volterra Competition Model:
Reslource competition (exploitive):
direct or indirect conflict over the same resource
Intraspecific competition:
Habitat selection and dispersal
Density dependant impacts on growth
Interspecific competition:
Interactions between species, populations
Interspecific competition model only contains alpha hald of full competition model.
Competitive Exclusion CCCC
Complete competitors cannot coexist
Resource partitioning: diff organisms within an ecosystem split up an area so they don’t compete for same resource.
describe resource (exploitative) competition - provide example
ADAPTATION TO COMPETITION
- diet
- behaviour
- time
- space
examples:
SAVANNA BROWSERS
- space (variation in heights from small springer to giraffe
NECTAR FEEDERS
- Bees: durinal
- bats: nocturnal
- direct/indirect conflict over same resource
- resource partitioning occurs via niche differentiation
Desert Plants
compete for water and nutrients
Have different root structures - size and length which can absorbs nutrients from different soil layers
different structures above ground competing for light and space
Describe Ecological character displacement and provide an example
The evolutionary accentuation of phenotypic differences between species stemming from selection to lessen resource competition or reproductive interactions between them
EG: Salamanders
Snout-vent length differs between allopatric and sympatric populations of plethodon cinereus and plethodon hoffmani.
EG Birds
Beak size differs between bird on the same island but is the same when those birds are on separate islands.
Describe inference competition and provide an example
One organism physically restricts another’s access to resources (territoriality, allelopathy)
Energy and resources are wasted in the form of aggression and evasive responses
Allelopathy: he chemical inhibition of one plant (or other organism) by another, due to the release into the environment of substances acting as germination or growth inhibitors.
Territoriality: noisy miners accounts for 66% of aggressive interactions, removing them doubles the foraging rate of small woodland birds
Apparent competition:
Explain how a shared enemy or third species can lead to apparent competition, and how you might experimentally assess the mechanisms underpinning species abundance pattern
apparent competition:
two species who do not share any resources but whose numbers change in relation to one another because of an indi- rect effect of a third species, typi- cally a shared predator or natural enemy.
Testing apparent competition: caribour decline example:
Deer and moose pops increase, increases pop of predators, causes caribou pops to decline
Habitat altercation-ultimate cause of decline
Maternity penning
Wolf removal
Moose removal
Control
translocation
Mutualism:
Explain the key types of resources shared in different mutualisms, and how researchers have established (and refined) our understanding of mutualisms
Shrimp and goby relationship
house (provided by shrimp) for sense (provided by goby)
Mycorrhizae (fungi)
Food for food
Plant provides sugar for fungi
Fungi provides nutrients (phosphorous and nitrogen)
- ecto (outside cells)
- endo (penetrates cell walls - more nutrient transfer)
Plants and grazing
cows and plant production
Sustainable grazing assists plant growth - can become negative
Food for mates
Penguins
Birds and seeds, after digestion seeds increases germinations success some species.
Pollination, plant&pollinator or semi-parasitic sexually deceptive orchids
Whats an example of herbivorous/mutual interaction
Elephant, Ants, Acacia
Elephants feed on acacia
Ants only present on acacias where elephants are present
With elephants absent, Ants more present on acacias in black soil
define the 3 community classifications
Physically defined
By discrete habitat boundaries
Assemblage of species in a particular place
Lakes, ponds
EG: Rainforest
Taxonomically defined (Taxocene)
Organisms of a particular taxon occurring together in one place
EG: rocky shore molluscs
Interactively defined community
Subsets of species in a particular place/habitat whose interactions significantly influence their abundance
Not common
EG: North Carolina salamander influence the abundance of any other spp
interpret the 2 population growth models
- Geometric/exponential: continuous function
growth and decay - Logistic: limited by K, carrying capacity of an organism
Define the three survival curves
Type 1: most individuals survive to an old age
Type 2: constant risk risk of mortality at all ages
Type 3. mortality at young ages
What is the purpose of the the Lotka-Volterra competition model;
Lotka-Volterra competition model is a mathematical model used to describe the interactions
between two competing species in an ecological community. The model consists of two main
variables:
Population Size:
N1: Population size of species 1.
N2: Population size of species 2.
how do communties assemble across a landscape
- Alpha
diversity within a local habitat
number of species and evenness in a particular area - Beta diversity:
measures the variation in species composition between different
habitats or locations within a given region.
High beta diversity indicates distinct communities
with unique species compositions, while low beta diversity suggests similarity in species composition
between communities.
- Gamma diversity:
Represents the overall diversity at the regional or landscape
level.
It encompasses the total species richness and ecological variation across multiple habitats or
locations within a larger area.
Gamma diversity considers both the local (alpha) diversity within
individual habitats and the turnover (beta) diversity between those habitats.
Using examples, explain the theory and its developments for how equilibrium communities are
maintained. (hint: theres 4 theories)
- Equilibrium theory:
emphasizes the role of ecological interactions and feedback mechanisms in
maintaining equilibrium communities. (competition, predation, mutualism)
EG: predator prey in a forest, numbers fluctuate and dictated by one another. - Succession and disturbance theory
succession after a natural disaster
Eg: volcanic eruption kills species and allows colonisation and competition of new species untill equilibrium is reached. - Intermediate disturbance:
suggests that
periodic disturbances at intermediate frequencies can promote species diversity and maintain
equilibrium communities.
EG: fires moderate grazing levels in savannas, creates opportunities for species to exist - Non equilibrium
shifting community patterns due to patchy environmental conditions
define alternate stable states, provide 2 examples
refers to different configurations or states that exist within a system under similar enviro conditions
- coral (healthy) vs algae (pollution, human impacts)
- Grass dominated vs shrub dominated lands - changes on rainfall, fire, moisture,
provide 2 examples of a top down trophic cascade
- Otters, Urchins and Kelp
- Wolves, elk and grazing
GPP vs NPP
Gross energy capture by primary producers
Net energy produced by Primary produces - used by other consumers (left over after primary producer)
