lecture 9 and 10

lecture 9 and 10 - Lecture 9 10 SOME STUDY NOTES FOR FOOD...

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SOME STUDY NOTES FOR FOOD SHORTAGES TO SEXUAL REPRODUCTION Review from last week: large temporalis and small massator – predator/carnivore small temporalis and large massator – herbivore scats – owls rolling into balls their food as waste (pellets come out the mouth) only mammal with poison bite – pointed nose shrew (short tail shrew – only animal with poison bite in NA) – analogous with idea of insects with poisonous bites predators – tend to get highest levels of toxins in their body because of bioaccumulation (ie DDT found to effect falcons and larger birds of prey, including behavioural changes, eggshell fragility) Injury is always a possible consequence of being predatory/prey. Also possibly face starvation because have to search for and capture prey, lack resources possible People don't like animals that hunt – ie Ontario coyotes can be shot some animals get caught in snares – bear traps animals that hunt face persecution still today, lack knowledge re value of predators effects of predators on prey is huge driving force in natural selection large number of prey series, like white tailed deer in Ontario, but because population is too dense, there has been a winding down of the deers via malformations/birth defects, lack of food due to large numbers of deer. ..natural selection weeding its way through an overpopulation crisis human trophy hunting often looks for best animal in the population, so serves as a negative factor regarding the overpopulation issue, which is the opposite of what predators do 2 ways to get a meal: eating animals from the inside out (who live in bigger animals) often when animal is still alive (which will eventually die – which is called parasitoids OR the parasites that can survive it); and many predators eat from the outside inward Parasitoids kill animals their eating from the inside of it. These include: Wasps: Braconids; Ichneumons ; also spider wasps; thread wasps; thread-waisted Flies: Flesh fly ; Bot fly; Tachinids Cocoons is around pupil case, and inside is a grub of a wasp – on back of caterpillar these developing wasps has over 100 parasitoids in its body leaving over 100 cocoons housing these wasps – killed the caterpillar eventually flesh fly eats from inside out of turtles – re turtle eggs beetles – parasitoids specialized to snake eggs the host is the animal that receives the eggs of the parasitoids, who must find and choose the right kind of animal to suit their developing needs (ie caterpillar size – can't choose one that is about to change into butterfly, because it will fly away!) sphinx moth caterpillar – eye spot – a flesh fly (parasitoid) walked up and down the caterpillar until it ovapositor on the host – egg injected into the skin of caterpillar some parasitoids lay eggs on beetle grubs under bark of trees dead or dying trees harbor beetle grubs, insects take advantage of tree and eat the wood. Ichneumon Wasps walk around these tree trunks, trying to find vibrations of beetle grubs
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This note was uploaded on 08/13/2008 for the course BIOL 1902 taught by Professor Runtz during the Winter '08 term at Carleton CA.

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lecture 9 and 10 - Lecture 9 10 SOME STUDY NOTES FOR FOOD...

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