Symbiotic Symbiotic RelationshipsRelationships

Who gets along? Who doesn’t?Who hurts who?

Species Interactions5 basic types of interactions of species within an ecosystem.1. Interspecific competition – When members of two or more

species interact to gain access to the same limited resources. 1. ie: food, light, space

2. Predation – when a member or group of members of one species feeds directly on another species.1. Usually animal to animal2. Rare cases of plants to animal

3. Parasitism – when one species feeds on/in the body of another species and harms it.

4. Mutualism – interaction of two species when both benefit from the interaction.

5. Commensalism – interaction of two species when only one benefits from the interaction and the other is not harmed or benefited.

Species Interactions• Interactions have a significant effect on the resources used and the

population of different species within the ecosystem.– b/c of these interactions the ability to reproduce and or survive is

influenced.• Natural selection takes place through interactions.• The most common interaction is competition.

– For limited resources– Requires one species to have the ability to be more efficient than

another when finding and utilizing resources like food and shelter.– The role species play in an ecosystem is considered their ecological

niche. (ie: the job they have, how they act towards their environment, what they do in their environment)

– When species compete for food, shelter, light; their niches overlap. The more overlap the more intense the competition.

Species InteractionsSpecies Interactions

• Predation (predatory-prey interaction):– Most consumer species feed off of other consumer

species.– Herbivores – feed off of plants and other producer

type species.– Omnivores – feed on plants and other living

consumers.– Carnivore – feed on other living consumers only– To survive predators must eat other prey, without

they would die and the evolution of the species can be stunted.

Species InteractionsPredator/Prey cont.• Predators – a closer look…– Methods used to capture prey:• Herbivores – simply walk, swim or fly to the plant when

needing to eat.• Carnivores/Omnivores – have moving prey so there are

a few main types of capture to eat.– 1. Pursuit – run, chase prey until they wear them out or catch up to

capture and eat.» Usually a single predator after a single prey.

– 2. Ambush – When one or more predators lay in wait or similar techniques to capture and eat prey» Hunting is an organized way to ambush prey, seen from lions,

wolves, humans, pack type organisms.» Camouflage – The predator disguises themselves to ambush the

prey.– 3. Chemical Warfare – Predators use venom or poison to attack prey

» Venomous snakes and spiders spit on or bite a prey organism and wait for them to immobilize before eating them.

Species InteractionsPrey – A closer look…• Evolved/Adapted to avoid predators:– Being able to move fast, quick reflexes (long legs, strong

muscles)– Highly developed sense of sight, smell or hearing (large eyes,

ears, nose)– Avoidance adaptations like shells (turtles), thick bark (giant

sequoia), spines (porcupines), and thorns (rose bushes, cacti)– Camouflage – being able to blend into their environment so as

not to be easily seen. (the moth, chameleons, cuttlefish)– Chemical Warfare – discourage predators to eat them

• by having a Warning Coloration… bright colored markings like red, orange, yellow, blue; all with usually black markings. (some frogs, snakes, salamanders)

• This lets the predator know that they are poisonous or taste bad and should not be eaten. (oleander, monarch butterfly)

Species InteractionsPrey cont.

– Foul smelling, gives off a nasty odor when startled or caught (skunks, skunk cabbage, stinkbugs)

– Irritating – gives off a chemical or needles that irritate the predator. (bombardier beetle, stinging nettles)

– Mimicry – acting like or looking like an organism that is poisonous so as not to be eaten (viceroy butterfly looks like the monarch)

– Living in large groups so as to not to be the one most likely eaten (schools of fish – tuna; Zebras)• Usually the one captured and eaten are the sick, old or young of

the group.

Symbiosis

Three types of Symbiotic relationships between organisms:– Mutualism – both organisms benefit from the interaction.

– Commensalism – One organism benefits, the other organism is not harmed or benefits from the interaction.

– Parasitism – One organism benefits, the other organism is harmed, but may not always die during the interaction.

Looking at pics