Species Relationships and Population Dynamics APES Mr. Hudson APES Mr. Hudson

Five major types of interaction Interspecific competition- two or more species compete for same resources (food, light, space) Intraspecific- competition between same species Predation-predator eats prey Parasitism- one benefits, one is harmed Mutualism-both benefit Commensalism- one benefits, one not harmed Interspecific competition- two or more species compete for same resources (food, light, space) Intraspecific- competition between same species Predation-predator eats prey Parasitism- one benefits, one is harmed Mutualism-both benefit Commensalism- one benefits, one not harmed

Competition Exists b.c of an overlapping of niches Examples- humans compete with many species for resources Especially as our ecological footprints grow Exists b.c of an overlapping of niches Examples- humans compete with many species for resources Especially as our ecological footprints grow

Predation One species feeds off another Form a predator-prey relationship- -this evolves over time DIFFERENT THAN detrivores (detritus feeders) or decomposers- --how? One species feeds off another Form a predator-prey relationship- -this evolves over time DIFFERENT THAN detrivores (detritus feeders) or decomposers- --how?

Predation Form a predator-prey relationship--this evolves over time This relationship driven by natural selection Only animals with specific advantageous traits/adaptations will survive Example-- camouflage, chemical warfare, mimicry--all for preds/prey Form a predator-prey relationship--this evolves over time This relationship driven by natural selection Only animals with specific advantageous traits/adaptations will survive Example-- camouflage, chemical warfare, mimicry--all for preds/prey

Camouflage Predator Prey

Snake catepillar

Chemical warefare Use chemicals to capture prey or keep predators away Preds--snakes, spiders Prey--skunks, stinkbugs “Bad taste animals” - monarch butterflies Bombardier beetle--bomb beetlebomb beetle Use chemicals to capture prey or keep predators away Preds--snakes, spiders Prey--skunks, stinkbugs “Bad taste animals” - monarch butterflies Bombardier beetle--bomb beetlebomb beetle

Coevolution Pred/prey interact for a long period of time, changes in gene pool for both species will form Example--bats use sonar to catch moths Some moths evolved ears sensitive to echo frequency--would fly to ground when frequency heard Bats began changing frequencies to catch moths “arms race” between species Pred/prey interact for a long period of time, changes in gene pool for both species will form Example--bats use sonar to catch moths Some moths evolved ears sensitive to echo frequency--would fly to ground when frequency heard Bats began changing frequencies to catch moths “arms race” between species

Parasitism One species benefits (parasite), the other is harmed (host) Ticks, tapeworms, lampreys, cow birds One species benefits (parasite), the other is harmed (host) Ticks, tapeworms, lampreys, cow birds

Parasite--host relationships also Coevolve Example--malaria cause by mosquito bites Body attacks parasite with antibodies, parasite has evolved thousands of proteins to keep it attached to RBC When immune system realizes this, parasite will change to another protein Example--malaria cause by mosquito bites Body attacks parasite with antibodies, parasite has evolved thousands of proteins to keep it attached to RBC When immune system realizes this, parasite will change to another protein

Mutualism Both species benefit Bees and flowers--bees eat nectar, spread pollen to other flowers Both species benefit Bees and flowers--bees eat nectar, spread pollen to other flowers

Commensalism One benefits, one isn’t harmed Example--epiphytes One benefits, one isn’t harmed Example--epiphytes

Natural Selection reduces competition for resources Animals instinctively want to survive with least amount of resistance

Niche/Resource partitioning