lecture 13: species interactions Flashcards
(17 cards)
How is herbivory different from carnivory?
herbivores typically do not kill the plants they eat
– Remove leaf, bark, stems, roots, sap
* Influences a plant’s ability to grow, survive and reproduce
Plants are in an evolutionary arms race with herbivores
What evolutionary responses have plants developed against herbivores?
Physical, chemical, and behavioral deterrents.
What is symbiosis?
An intimate relationship between two organisms that can be positive, negative, or neutral.
Define parasitism, mutualism, and commensalism in terms of effects on species.
Parasitism: + / -
Mutualism: + / +
Commensalism: + / 0
Why don’t parasites usually kill their hosts?
Killing the host would destroy the parasite’s source of habitat and food.
What are the consequences of parasitism for the host?
Decreased reproduction, increased mortality from infections and predation, and abnormal behavior.
Difference between ectoparasites and endoparasites?
Ectoparasites live on the host’s exterior; endoparasites live inside the host.
What are microparasites and macroparasites?
- Microparasites: small (viruses, bacteria), short infections, direct transmission.
- Macroparasites: large (worms, ticks), long infections, indirect transmission.
How are parasites transmitted?
Direct transmission: contact or environmental dispersal.
* Indirect transmission: involves an intermediate host or vector.
How can parasites regulate host populations?
They act as density-dependent regulators, causing population oscillations.
What is an example of a complex host-parasite relationship?
Brainworm (meningeal worm) in white-tailed deer, with snails as intermediate hosts.
What is mutualism?
A relationship where both species benefit, enhancing survival, growth, and/or reproduction.
How does mutualism affect population models?
Positive influence in Lotka-Volterra equations; species j increases K for species i.
Give an example of mutualism.
Coral and algae: algae provide energy and O2 through photosynthesis; corals provide COz and nutrients.
What is commensalism?
A relationship where one species benefits and the other is not significantly affected. +/0
Examples of commensalism?
Barnacle and whale: barnacle gains space and transport.
* Remora and shark: remora gains food, protection, and transport.
if host has parasite what happens to its energy
uses energy to defend against the parasite – redirects energy from growth and reproduction
