BI303 - Section 2 Lecture 4

What is the definition of a parasite?

an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense.

How do parasites typically affect their hosts?

They cause harm but not immediate death

What types of organisms can be parasites?

Bacteria, protozoa, flatworms, nematodes, arthropods

What is a rare occurrence in natrual environments regarding parasites?

Not harbouring several species of parasites

What are holoparasites?

Parasites that lack chlorophyll and depend on hosts

What are hemiparasites?

Parasites that can photosynthesise but need hosts

What is an exampke of a holoparasite?

Rafflesia arnoldii

How can parasites be categorised?

Monophagus v. polyphagous.
Microparasites v. macroparasites.

What is the difference between ectoparasites and endoparasites?

Ectoparasites live outsie, endoparasites live inside hosts

How do some parasites manipulate behaviour?

By making hosts more susceptible to predation

What is an example of a parasite that affects rodent behaviour?

Toxoplasma gondii

How do larger ants avoid parasitism by fly larvae?

By foraging atnight when it's dark

What is the effect of parasitism on host populations?

It has strong effects, often hard to measure

What are antagonistic biotic interactions?

Associations where one benefits at the expense of another.
Examples include competition and predation.

How does herbivory affect plants?

Variable effects on growth, survival and fecundity.
Plants evolve strategeis to avoid herbivory; avoidance, tolerance and defense.

What types of defences have plants evovled against herbivory?

Physical defenses.
Chemical defenses (qualitative or quantitative).
Induced defenses.