Exam 1 study guide

Exam 1 study guide - 1 In Australia biologists have discovered that when the ranges of two species of Eucalyptus trees meet they form a hybrid zone

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 . In Australia, biologists have discovered that when the ranges of two species of Eucalyptus trees meet, they form a hybrid zone. In this hybrid zone, herbivorous insects and fungi are significantly higher in species richness than in either of the ranges where the tree species are separate. Why? (2 hypotheses) - Eucalyptus trees usually have toxins, however, being a hybrid may have eliminated this trait and therefore all kinds of species can thrive. 2 . Large hawks of the genus Buteo all forage for prey by soaring at heights in the air column and diving on prey. Species of this genus that feed on birds and mammals tend to exhibit polymorphisms (multiple color forms) in breast color (black, brown or white). Species of this genus that feed on insects, frogs and crayfish tend to be monomorphic (single color form) in breast color (each species with a consistent breast color). Why? (2 hypotheses) - the polymorphic hawks have to camouflage themselves from predators who may be feeding off the same birds and mammals as well as camouflage from the prey down below. the monomorphic hawks have less competition with larger predators because of their choice of food, therefore they only need one color to camouflage from their prey for better capturing techniques -It would also have to do with what time of day the hawk hunts. If it hunts in the night, it’s more conducive to it to be black. Likewise if it hunts in the day time, it would be better for it to be white. -Also, it is the rarest color that has the advantage in any biome. The hawk doesn’t succeed every time it hunts. Therefore, the prey becomes condition to a certain color of hawk and they will avoid that color more often. However, if you (being the hawk) were the rarest color of all the hunting hawks. The prey will be less skittish of you and thus your hunting results will be much better. -Wanting to be in a different "niche" of color to eliminate some competition. Sub-colors divide into different chest colors for different time of day to minimize competition. -Different breast colors allows for genetic variation and so the female's offspring will always be the rarest color (most desired color) because the colors will alternate. 3 . Orchids can be artificially cross-pollinated with virtually any other orchid species. Yet, in the wild this rarely occurs. Throughout Latin America, a group of Orchid Bee species is a common pollinator of orchids, but these bees are NOT specialized. Each bee species will pollinate between five and ten different species of orchids. How is cross-pollination between orchid species avoided? (Two hypotheses) -There are more costs to being a hybrid than being a pure-bred; many hybrids are infertile, adaptations are for only half of both parents = not VERY good at any one thing just okay at two. Time of season. At any one time there is only one kind of orchid available
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 01/07/2012.

Page1 / 3

Exam 1 study guide - 1 In Australia biologists have discovered that when the ranges of two species of Eucalyptus trees meet they form a hybrid zone

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online