to look inedible. camouflage.

(look like a leaf, or bark, etc)

Physical- spines, low nutritional value

Biochemical warfare- blocks digestion and slows growth

Secondary Compounds- toxins made for defense

- when a plant has resistance to ALL organisms

- multiple genes involved

- phenotype=bark, lignin, terpenoids

- 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.

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

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

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

- Competition within a species

- increase density, increase competition

- Competition between 2 different species

- Causes depression in both species populations

- increase comp, decrease resources, may lead to extinction

- Coined the word ecosystem

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

1. ignition

2. fuel

3. weather (wind especially)

4. topography

Each species performs a complementary function for the other

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

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

ex: fish/shrimp "cleaning stations"

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

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

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

- areas where community boundaries are clearly visible

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

- 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

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

-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)

He pioneered succession studies

- succession is linear

- each species paves way for the next

- the ultimate association of species achieved is called climax community

He studied sand dune succession

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

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

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

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

- Not necessarily a forest

- Species are no longer replacing each other

small area of homogeneous habitat

turnover in species from one to another

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

- locally more dense populations

Any species that is not native to that ecosystem

1. european rabbits

2. cane toads

3. zebra mussels

4. shiprats

5. domestic pigs