“living together”

one organism benefits by feeding on another

prey = host host is harmed or weakened differentiate between predators and

parasites…parasites are usually smaller and more

numerous than hostparasites usually have complex life cycles

coevolution…examples include malaria and sleeping sickness

LIVER FLUKE

both organisms benefit examples…

lichensbacteria living in the digestive tracts of

cows and termitesants and acaciamycorhizae and legumes

lichens

WHITEBARK PINE AND CLARK’S NUTCRACKER

one species benefits and the other is relatively unharmed

controversial – why???examples – barnacles on a whale

GREAT WHITE SHARK AND REMORA

predators kill and eat other organisms some scientists include herbivores

(plant-eaters) in this category predators are usually larger and less

abundant than their prey

yes, it’s a predator!

these interactions result in coevolution evolution of camouflage, skilled hunting

ability, poisons some examples

counteracting behaviors –bats and moths

some examples (continued)camouflage – colors,

patterns and shapes that resemble surroundings, these organisms do not flee – cheetahs, frogfish

warning coloration – usually bright, these organisms taste bad or are poisonous

some examples (continued)mimicry – one species has evolved

resemble another Müllerian mimicry – occurs among different

distasteful species such as monarch butterfly (poisonous) and viceroy butterfly (distasteful)

some examples (continued)mimicry

Müllerian mimicry – results in faster learning by predators such as the black and yellow color pattern that is repeated in nature

some examples (continued)mimicry

Batesian mimicry – harmless animals resemble poisonous ones

some examples (continued)mimicry

startle coloration – patterns of color that resemble much larger/dangerous organisms

some examples (continued)mimicry

aggressive mimicry – predators entice prey to come close by resembling something attractive to them

the real deal…only about 10 cm long

some examples (continued)chemical warfare – both predators and prey

use toxic chemicals plant poisons venomous snakes and spiders ink emitted by certain mollusks

some examples (continued)plants and herbivores have also coevolved

milkweed is toxic to all organisms except the monarch butterfly…these butterflies store these chemicals and use them as their chemical defense weapon

change in teeth of grazing animals to be able to eat grasses that have evolved to have a hard outer covering (made of silicone)

competition – occurs when a resource is limited

intraspecific vs. interspecific competition

classic studies of competitionParamecium caudatum and

Paramecium aurelia – showed that 2 species with similar requirements cannot coexist (for an extended time period)

classic studies of competition (continued)warbler study – each

species occupies its own niche

niche – all aspects of an organism’s habitat, how it “makes a living” and its physical environment

no/minimal niche overlap = no competition

classic studies of competition (continued)barnacle study - by excluding each species

it was determined that they could both inhabit the low tide areas

fundamental niche - set of resources a population is theoretically capable of using under ideal conditions

realized niche - the resources a population actually uses

competitive exclusion principle (Gause’s Principle)Two species competing for limited

resources cannot coexist in the same place at the same time.

click this box!

organisms with high biotic potential that are introduced (accidentally or purposely) into non-native ecosystems where there is little environmental resistance biotic potential – maximum reproductive ability in an

optimal environment so what’s the big deal? they can effect…

natural resources human health economy

invasive species have no predators, diseases, parasites, other organisms competing for the same resources and limiting environmental factors

click on this carp guy

disrupt natural communities and ecological processes

cause harm to the native species in that ecosystem by competing with them for the same resources

invasive species can outcompete native species

ecosystems often become less biodiverse (more susceptible to further damage)