Ch. 12 Competition

Question 1

Venus flytrap

Answer 1

• has modified leaves that attract insects with nectar
• inner surface has touch-sensitive hairs
• if an insect trips those hairs, lead snaps shut in half a second

Question 2

Pitcher plants

Answer 2

• lure insects into a pitcher-shaped trap
• inside of the pitcher has downward-facing hairs, which make it easy for the insect to crawl in, but hard to crawl out
• about halfway down, many pitchers have a waxy layer that sticks to insects feet, causing it to tumble into a vat that contains water or digestive juices

Question 3

Why do some plants eat animals?

Answer 3

• competition among plants can be intense where soil nutrients are scarce
• in nutrient-poor environments, carnivory in plants has evolved multiple times

Question 4

Experiment with pitcher plant

Answer 4

• removed noncarnivorous competitor plants
• some pitcher plants were starved
• growth rates increased when competitors were removed
• with neighbors intact, and pitchers covered, growth rate was not reduced as expected.. why?

Question 5

Competition

Answer 5

An interaction between individuals in which each is harmed by their shared use of a limited resource

Question 6

Interspecific competition

Answer 6

Between members of different species

Question 7

Intraspecific competition

Answer 7

Between individuals of a single species

Question 8

Limited resources

Answer 8

• features of environment required for growth

- which can be consumed to point of deletion

Question 9

Examples of resources that can be consumed to depletion:

Answer 9

• food
• water in terrestrial habitats
• light for plants
• space, sessile organisms
• space for refuge, nesting, mobile organisms

Question 10

Species also influenced by factors that are not consumed or depleted, such as..

Answer 10

• temperature
• pH
• salinity

Question 11

Can’t have competition if resource is not ___.

Answer 11

Limited

Question 12

Biases for the analyses of the study of the study showing that competition had significant effects on a wide range of organisms

Answer 12

• researchers may not publish studies that show no significant effects
• tendency for investigators to study species they suspect will show competition

Question 13

Ghosts of competition past

Answer 13

Don’t see competition today, but today’s interactions were shaped by competition in the past

Question 14

Exploitation competition

Answer 14

• species compete indirectly through their mutual effects on availability of a shared resource

Question 15

Interference competition

Answer 15

Species compete directly for access to a resource

Question 16

Antagonistic actions

Answer 16

Ex: when two predators fight over a prey item
Ex: when voles aggressively exclude other voles from preferred habitat

Question 17

• Allelopathy

Answer 17

Individuals of one species release toxins that harm other species

Ex: spotted knapweed

Toxin called catechin

Question 18

Competitive exclusion

Answer 18

When one species drives another to extinction

Question 19

In many cases the effects of competition are unequal, or ___.

Answer 19

Asymmetrical

Question 20

Amensalism

Answer 20

Individuals of one species are harmed while individuals of the other species are not affected at all

Question 21

Niche overlap

Answer 21

The extent of common requirements of resources between two species

Question 22

Competitive refuge

Answer 22

Ex: semibalanus dried out and survived poorly at the top of the intertidal zone

Question 23

Removal experiments

Answer 23

Idk

Question 24

Natural experiment

Answer 24

A situation in nature that is similar in effect to a controlled removal experiment

Question 25

Ecological niche may be considered an..

Answer 25

"n-dimensional hyperspace"

Question 26

Resource partitioning

Answer 26

Two species "share" a resource.. they use it differently Niche differentiation

Question 27

Competitive exclusion principle

Answer 27

Two species that use a limiting resource in the same way can not coexist

Question 28

Niche breadth

Answer 28

"Width" of niche space Breadth is reduced when competition is present

Question 29

* How might one experimentally test if distribution is due to competition or some other factor?

Answer 29

Idk

Question 30

Two Cyanobacteria species in the Baltic Sea

Answer 30

- Red BS1 absorbs green wavelengths most efficiently - Green BS2 absorbs red mist efficiently - each species could survive when grown alone in either wavelength - when grown together, one drove the other to extinction, depending on the wavelength used - under white light, they both persisted

Question 31

Two Cyanobacteria then studied in lakes and oceans

Answer 31

- only red Cyanobacteria were found in clear waters - only green Cyanobacteria were found in turbid waters - both were found in intermediate waters - able to coexist because they are partitioning the light resource

Question 32

Competition coefficients

Answer 32

Alpha and beta

Question 33

Lotka-Volterra competition model

Answer 33

can be used to predict the outcome of competition Supports the idea that competitive exclusion is likely when competing species require very similar resources If competing species use the same resources in a similar fashion -> one will likely go extinct

Question 34

* Competitive reversal

Answer 34

An inferior competitor in one habitat, or under different conditions, may become the superior competitor in another Ex: Tansleys bedstraws

Question 35

Example of competitive reversal

Answer 35

When ragwort flea beetles were introduced to western Oregon, biomass of ragwort, an invasive species, decreased, and its competitor species increased In a sense of flea beetles, ragwort is superior competitor

Question 36

Disturbances

Answer 36

Fires or storms

Question 37

___ such as fires or storms can kill or damage individuals, while creating opportunities for others.

Answer 37

Disturbances