Ecology Lecture Notes Review

Flashcards covering key vocabulary and concepts from ecology lecture notes, focusing on niche concepts, microbial adaptations to extreme environments, population ecology, life histories, competition, mutualism, community ecology, ecological networks, decomposition, and the nitrogen cycle.

Species Distribution

The distribution of a species is determined by abiotic factors, resource requirements, and inter-specific interactions.

Conditions

Natural or anthropogenic environmental conditions.

Organisms Performance

Organisms survival, growth rate, and reproduction define its environmental performance.

Long term persistence threshold

A condition where the intrinsic rate of increase (r) is greater than or equal to 0, allowing long-term survival.

Response curves

Monotonic (decreasing) or unimodal (centered) graphs showing organismal response to environmental gradients.

Niche concept

A unifying framework that utilizes multiple conditions and resources to define limits on an organism's persistence, visualized as niche dimensions or axes.

n-dimensional hypervolume

A multi-condition and resource limit distribution; organisms live inside this space.

Fundamental niche

The complete hypervolume representing the full range of conditions and resources where r≥0.

Realised niche

The volume occupied in the presence of competition and predators.

BAM framework

A framework evaluating species distribution based on Biotic factors, Abiotic factors, and Migration.

Extremophile

An organism that grows optimally under one or more extreme physical conditions.

Psychrophiles

Organisms that grow optimally below 15°C.

Thermophiles

Organisms that grow optimally between 45-80°C.

Halophile

Organisms that grow optimally in salinity levels above 8.8%.

Hyperpiezophile

Organisms that grow optimally above 50 MPa.

adaptations to psychrophily

Protein enzymes with more flexible α-helices, high polar amino acid content, and fewer ionic/hydro bonds to adapt to cold environments.

hyperthermophile adaptations

Stabilizing proteins with high hydrophobic cores, disulphide bonds, and chaperones (HSPs) to adapt to extreme heat.

salt in

accumulation of K+ and Cl- = osmolytes energetically less expensive

Fermentation

ATP formed by substrate level phosphorylation

Anaerobic respiration

form of PMF (proton motive force) via oxidative phosphorylation with other e acceptors not O₂

Density independent factors

Reduce/increase pop by same proportion due to abiotic factors

Density dependent factors

Alter depending on pop density due to biotic factors

Assessing pops

Measures – counts,densities, age structure, sex ratios, birth rate, death rate, immigration, emigration.

Logistic growth model

Model that shows initial exponential increase followed by slowdown as resource becomes limited

Life history traits

Allocation of time and E goes towards uses

Mutation accumulation hypothesis

Failure to repair due to accumulation of deleterious mutation

Antagonistic pleiotropy hypo

Trade offs between repair and reproduction.

semelparity

Single repro event

Iteroparity

Multi repro events

R- selected sps

live fast,die young

K- selected sps

stable environments, steady resource turnover

genets

gen indi via sexual repro

ramets

asexually prod indis from same gen parent (eco importance)

pop structure

Ani – age struc (no. of indi in dif age classes in pop), 3 classes – pre-repro,repro,post repro (affect pop growth)

neg dense – dep

Phenomenon where plnt respond to resource comp by slowing growth, self thinning (less indis more biomass)

pos dense – dep: allee effect

Phenomenon where there is an incr in repro/surv with incr dense

Competitors

Fast growing sps that inhabit high fertility, low disturbance sites (maximize captured resources)

Stress tolerators

Slow growing sps that inhabit low-fertility, low disturbance sites (conservation of captured resources)

Ruderals

Fast growing spsthta inhabit high fertility, high disturbance sites (high seed production)

Competition

Interaction by shared requirement for a resource in limited supply, direct or indirect, signif affect surv/repro of compet indi or sps

scramble competition

Indirect comp resources divided approx equally among competitors, indi exploit resource, reducing availability, lead to boom-bust dynamics, over exploitation =pop crashes

Interference competition

Direct comp where indi interact directly, monopolise/contest resource, stabilises pop dynamic as dom indi secure resources, prevent over-exploitation

Apparent competition

Comp between 2 org not via resource but by pred or parasite, increase in 1 sps = incr in pred/para pop, then negatively affects the other sps

gause’s law

Models where no 2 sps can coexist indefinitely on the same limiting resource and one sps will outcompete the other

Shade avoidance syndrome

The collection of resp to vegetative shading, delayed/ suppressed germination, stem and hypocotyl elongation, petiole elongation, narrow lvs, early flwr

Allelopathy

Production of chem released by plants influe direct/indirectly the growth/development of neighb plnts

Aarssen’s general evo theory of comp

Balance Between supply and demand, Strength of comp, Resour partitioning

Fungal comp

Fungal-fungal, fungal-bacterial interactions

contact necrotrophy

Para contacts host hyphae, no pen, host cytop degens lysis may occur

Invasive necrotrophy

Para pens, enters host, rapid degen of host cytop, hyphal lysis

Intracellular biotroph

Entire thallus enters hypha, host cell still function

Haustorial biotrph

Short haustorial branch from para hypha pens host, host still function

Fusion biotroph

Host and para in intimate contact, micropore form between adpressed host and para hyphae/ short pen branch from para hypha, host functions

Mycostasis

Majority of fungal spores fail to germinate, correlated with microbial activity, alleviated if soil is sterilised, alleviated if easily available E sources, effect mediated by soil microbes

Prey in lokta-volterra model

Prey grow exponentially in absence of predators r*N

Predators in lotka-volterra model

Growth rate depends on prey density

The simplest host

SIR model

Basic repro number

Number of primary infection arising from one infected indi in a wholly suscept population

Predation

One organism (predator) consumes another (prey)

True Predators

Kill their prey immediately after capture

Grazers

Attack many prey individuals but remove only a part of each prey

Parasites

Consume parts of their prey (host); usually do not kill the host

Parasitoids

Lay eggs in or on another host organism, after which the larvae hatch and consume the host, eventually killing it

Escape

Traits to avoid being found by herbivores (spatial or temporal refuges)

Tolerance

Traits to reduce the negative impact of herbivory on plant fitness

Defence/Resistance

Traits that deter or repel herbivores or reduce herbivore performance

Structural Defenses

Physical barriers like thorns, spines, prickles, trichomes and sclerophylly

Chemical Defenses (Secondary Metabolites)

Organic compounds that deter herbivores

Talking Trees Hypothesis

Damaged plants release volatile compounds to initiate defenses in nearby plants

Allergies

Hypersensitivity to fungal antigens (e.g., inhaled spores)

Mycotoxicoses

Ingestion of fungal toxins (e.g., aflatoxin)

Mycoses

Fungus invading living tissue

Superficial fungal infection

No invasion of living tissue

Cutaneous fungal infection

Infections of hair, skin, or nails; no living tissue invasion, but allergic/inflammatory responses occur

Subcutaneous fungal infection

Chronic, localized infections following implantation of fungus

Systemic fungal infection- Dimorphic/True pathogen

Can invade healthy hosts; primary site is usually pulmonary. Morphology differs inside and outside the host

Systemic fungal infection - Opportunistic

Occur mainly in immunocompromised patients

Symbiosis

Close, long-term interactions (mutualism, commensalism, parasitism)

Facilitation

One organism benefits another (mutualism, commensalism)

Obligate

Species depends on symbiotic association

Facultative

Species benefits but isn't dependent

Plant Facilitation

Positive interactions: One plant enhances another's growth, survival, or reproduction

Nurse Plants

Adult plants creating favorable microhabitats for seedlings

Phenotypic Plasticity

Ability to exhibit different phenotypes in response to environmental variation

The 'Wood Wide Web'

Cooperation via ectomycorrhizal fungi

Commensal bacteria-plant interaction

Bacteria benefit without harming the plant

Parasitic bacteria-plant interaction

Bacteria cause disease in the plant

Mutualistic bacteria-plant interaction

Both bacteria and plant benefit (symbiosis)

Bacteriocytes

Specialized host cells that house endosymbiotic bacteria

Basis of Mutualisms

Nutritional, Habitat/environment mutualism

Biological Invasion

Typically human-mediated, occurring on smaller temporal scales than natural colonization

The 10s Rule

The probability of transitions during invasion

Carbon Cycle

CO_2 is the most oxidized form of carbon (+4)

The Nitrogen Cycle

Involves transformations between: Nitrate, Nitrite, Nitric oxide, Hydroxylamine, Hydrazine, Ammonium, Organic Nitrogen, Nitrogen

Nitrospira

Catalyze complete nitrification (comammox bacteria)