23. Community ecology: trophic relationships and plant-animal interactions Flashcards
Tropic Levels
(P 123C D)
Primary producers
Primary consumers
Secondary consumers
Tertiary consumers
Decomposers
Primary producers
plants
Primary consumers
herbivores
secondary consumers
carnivores who eat herbivores
tertiary consumers
carnivores who eat secondary consumers
decomposers
eat dead organic matter
food chain
follow just one path of energy as animals find food
food web
show how plants and animals are connected in many ways to help them all survive
Indirect effect
one species alters the effect that another species has on a third (fish to dragonfly)
Trophic Cascades: “HSS”
interaction between 2 trophic levels ‘cascade’ to a third trophic level
HSS trophic cascade
The world is green b/c carnivores keep down herbivores so herbivores don’t limit plant growth
Top-down control (ex: top of food chain)
abundances kept low because of predation (Experimental test = predator removal)
Bottom-up control (ex: bottom of food chain)
abundances kept low because of resource limitation (Experimental test = resource addition)
Plant- herbivore interactions as an arms race
Plants evolve toxins to reduce herbivory (milkweed); insects evolve detoxification or other mechanisms to overcome plant defenses (monarch caterpillars: specialist herbivores )
Some alkaloids important to humans
coffee- caffeine
coca- cocaine
tobacco - nicotine
opium poppy - morphine
The key to diversification is…
Plant-insect coevolution
