General Ecology

Crypsis

to look inedible. camouflage.

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(look like a leaf, or bark, etc)

Morphological Adaptions
spikes, spines, or armor
Batesian Mimicry
mimic the actions of an unpalatable species by a palatable species to deceive predators.
Mullerian Mimicry
mutual resemblance of two or more conspicuously marked, unpalatable species to enhance predator avoidance.
Defense against herbivory (3 examples)

Physical– spines, low nutritional value

 

Biochemical warfare– blocks digestion and slows growth

 

Secondary Compounds– toxins made for defense

Horizontal Resistance

– when a plant has resistance to ALL organisms

– multiple genes involved

– phenotype=bark, lignin, terpenoids

Vertical Resistance

– specific resistance to certain species

– caused by host recognition of protein from pathogen, plant then kills cells around the pathogen, and pathogen can’t feed and then dies.

Parasitoid
organism (usually wasps;flies) whose larvae consume tissue of the living host until the host dies
Endoparasitoid
parasitoid larvae inside of the host
Ectoparasitoid
parasitoid larvae outside of the host
Parasite
Organism that is smaller than it’s host and lives inside or outside the host. Organism lives off the host, must deal with host defense and sometimes has multiple hosts. (ie: mosquitos)
Gause’s Lab Results

Experiment– predator (didinum); prey (paramecium)

;

(pred;prey in beaker w/ nutrients)

exp 1 results – predators eat all prey, both go extinct

;

(add prey refuge)

exp 2 results – predators eat all available prey, some prey hide, predators go extinct, remaining prey rebound

;

(refilled extinct populations)

exp 3 results – reoccuring oscillations

Huffaker’s Mites

Experiment – prey (6 spotted mite); pred (other mite)

 

without increased dispersal, the prey was consumed and predators eventually died b/c of lack of food

 

pegs installed to increase prey survival

result: reoccuring oscillations

Predator-Prey Cycle Stability (5 factors)

1. Predator inefficiency

2. Density dependent limitations (disease, etc)

3. Alternate food sources for predators

4. Refuge from predators at low prey density

5. Reduced time delays in predator populations

Intra-specific Competition

– Competition within a species

– increase density, increase competition

Inter-specific Competition

– Competition between 2 different species

– Causes depression in both species populations

– increase comp, decrease resources, may lead to extinction

Liebig’s Law of the Minimum
The idea that the growth of an individual/population is limited by the essential nutrient present in the lowest amount relative to requirement
AJ Tansley

– Coined the word ecosystem

*** – ;Common Garden Experiment; – competition determines species abundance, environment affects competition outcome, and secregation of species may be from past competition

Exploitation (competition)
sharing of resources while competing
Interference Competition
Competition where there is chasing or releasing of toxic chemicals
Allelopathy
Chemical competition in terrestrial plants where toxic substances decrease fitness of neighbors
4 Factors that determine fire intensity

1. ignition

2. fuel

3. weather (wind especially)

4. topography

Fire Regime
Generalized way to describe fire intensity, severity, frequency, and vegetative community
Laddering
When surface fires move to canopy by igniting fuel from understory (causes more intense fires)
Coevolution
Populations of 2 or more species interact and evolve in response to characteristics of the other that affects its fitness
Convergent Evolution
Distant relatives evolve to look like each other because of similar environmental/physical stresses
Ehrlich ; Raven
These 2 men observed patterns of relationships and interpreted them as coevolution
Mutualism

Each species performs a complementary function for the other

Facilatative Mutualism
Mutualism when the species’ can still survive without the other
Obligatory Mutualism
Mutualism where the two species’ need each other
Trophic Mutualism

Type of mutualism that involves partners specialized to obtain energy/nutrients

;

ex: bacteria digest cellulose and cows use the products of bacterial digestion for metabolism

Defense Mutualism

Mutualism that involves the species that gets food/shelter for partners in return for protection

;

ex: fish/shrimp ;cleaning stations;

Dispersive Mutualism

Mutualism that involves species that receive food in return for transport of pollen/seeds

FE Clements

He stated:

;

-community (a holistic concept)-need to look at whole community, not just the species

– a closed system in equilibrium

-species are interdependent on others (superorganism)

– Communities haev discreet boundaries

-succession leads to the same community

HA Gleason

He stated:

;

– a community is an open system that is not in equilibrium and is a chance association of species

– species occur by coincidence and species are individualistic

– no distinct boundaries

– succession may lead to same community

– individualistic concept

Individualistic concept (by HA Gleason)
community structure and function is merely the interaction of individual species; not organization, no purpose above species level
Ecotone

– areas where community boundaries are clearly visible

– areas of rapid change in species in correspondence to rapid change of environment (pockets)

Continuum Concept

– within a broad, defined habitat, populations of plants and animals replace each other over the gradients of the conditions

;

– fits with an open system

– ecotones don’t occur along gradients of gradual change

– less species with overlaping distribution

Whittaker/ecological gradient
He stated that each species has their highest abundance and one point on the gradient but are found in most locations
Species richness
the number or species; often used at a measure of diversity (tells us about productivity)
Species guilds
groups of species that exploit the same set of resources in the community
Rarefaction

data are generated by drawing subsamples at random from the total sample to generate samples of equal size

Fundamental Niche
All the areas with conditions that are within acceptable range for the specific species
Realized Niche
Actual area where the species occurs, limited by dispersal, competition, predation, etc.
Bottom-up control
control where producers control production at the higher trophic levels
Top-down control
control where predators influence production of the lower levels
Organisms Control Dominants (Keystone Species)
Predation maintains the biodiversity of ecosystems, and if removed, certain prey can outcompete and limit biodiversity
Resource providers (Keystone Species)
the producer provides food for the entire ecosystem
Keystone mutualists (Keystone species)
where mutualism affects the community as a whole
Keystone engineers (keystone species)
their activity changes the environment and provides for multiple species
Community Dynamics

-communities are always in some sort of flux

-in stable communities, species composition tends not to change but individuals are replaced

-disturbed areas see a rebuilding period (succession)

FE Clements

He pioneered succession studies

 

– succession is linear

– each species paves way for the next

– the ultimate association of species achieved is called climax community

Primary Succession
the first plant growth when there was nothing there previously
Henry Cowles

He studied sand dune succession

 

bare ground>>grasses/herbs>>shrubs>>trees

SERES
Clements- stated any successional series is called (______), but each series has different pioneer plants
Facilitation

This supports Clements’ view of a developmental sequence which each species paves the way for the next

;

-grass gives nutrients for the shrubs, which give moist soil for trees, which shade out shrubs, and new trees shade out first trees

Species richness
Inhibition

One species inhibits the presence of another by exploitation competition or allelopathy/interference competition

;

-climax communities inhibit the growth of species from earlier stages

***- succession occurs through the death and replacement of established individuals during this process – leads to the shift towards longer lived species. earlier stages can only invade after disturbance

Tolerance

a species can invade a patch dominated by another – ex: shade tolerant trees creep in and become ;gap; species.

;

some superior competitors-grow slow, express dominance later

Climax Community

– Not necessarily a forest

– Species are no longer replacing each other

Local Diversity

small area of homogeneous habitat

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regional diversity
total number of species in all habitats within geographic area with no dispersal barriers
Beta diversity

turnover in species from one to another

;

Ecological Release

– on islands that have smaller species pools and species tend to expand realized niche

– locally more dense populations

;

Invasive species
Alien species whose intro causes economic/environmental harm or harm to human health
Alien Species

Any species that is not native to that ecosystem

;

Top Five invasives

1. european rabbits

2. cane toads

3. zebra mussels

4. shiprats

5. domestic pigs

Biomagnification
Increase in level of toxins as you move up the food chain. Higher level fish have higher toxin levels
Bioaccumulation
accumulation of toxins at a specific trophic level