Ch. 17 Biological Communities (pg. 361) How Organisms Interact in Communities Evolution in...
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Transcript of Ch. 17 Biological Communities (pg. 361) How Organisms Interact in Communities Evolution in...
Ch. 17 Biological Communities (pg. 361)
How Organisms Interact in Communities
Evolution in Communities
Interaction Among Species
Coevolution – the process in which long-term, interdependent changes take place in 2 species as a result of their interactions
Example: flowers and their pollinators
Predators and Prey Coevolve
Predation – an interaction between 2 species in which one species, the predator, feeds on the other species, the prey
Parasitism – a relationship between 2 species in which one, the parasite, benefits from the other species, the host, and usually harms the host
Plant Defenses Against Herbivores
Primary Defense – thorns, spines
Secondary compounds – Defensive compounds in plants
Ex.Make the plant taste badToxic compounds
How Herbivores Overcome Plant Defenses
Many herbivores have the ability to breakdown the secondary compounds – produce enzymes
Ex. Cabbage butterfly larva breakdown mustard oils that are toxic to most other insects
Monarch butterflies and milkweed
Symbiotic Species
Symbiosis – a relationship in which different organisms live in close association with each other
3 kinds of symbiotic relationships:
Mutualism
Commensalism
Parasitism
Mutualism – a relationship between 2 species in which BOTH species benefit
Flower and pollinator
Coral and photosynthetic algaeAnt and “milking” an aphid
A remarkable 3-way mutualism appears to have evolved between an ant, a butterfly caterpillar, and an acacia in the American southwest. The caterpillars have nectar organs which the ants drink from, and the acacia tolerates the feeding caterpillars. The ants appear to provide some protection for both plant and caterpillar.
© Gregory G. and Mary Beth Dimijian
Ant and acacia
The ant hollows out the large thorns of the plant for nests, feed on sweet secretions from the base of each petiole
Ants in return protect these trees from invertebrate as well as vertebrate herbivores. With any movement of the branch, the ants emerge releasing a nasty odor as well as physically attacking the surprised herbivore.
Commensalism – a relationship between 2 organisms in which one benefits and the other is unaffected
Whale with barnacles
Shark with pilot fish
Clownfish and sea anemone
Parasitism– a relationship between 2 species in which one, the parasite, benefits from the other species, the host, and usually harms the host
Tapeworm in carp
Tick feeds on blood of hostTapeworm
Competition – a relationship between species that attempt to use the same limited resource
How Competition Shapes Communites (pg. 365)
Common Use of Scarce Resources and Competition
Niche – the position (way of life) of a species in an ecosystem in terms of the physical characteristics (such as size, location, temperature, pH, etc) of the area where a species lives AND the function of the species in the biological community (position in food web, when it breeds, etc.)
No two species can occupy the exact same niche at the same time
Fundamental niche – the largest ecological niche where an organism or species can live without competition
(Realized niche – the range of resources that a species uses, the conditions that the species can tolerate and the functional roles that the species plays as a result of competition in the species fundamental niche)