Species Interaction

Questions for Today:

• What are the five ways species interact with each other?

• How does competition effect species interactions?

• Describe Predator-Prey Relationships and how those relationships creates a coevolution event?

• What are three types of symbioses found in nature?

Species Interact in Five Ways

• There are five basic types of species interactions:– Interspecific Competition– Predation– Parasitism– Mutualism– Commensalism

• These interactions help influence survival techniques which make them agents of Natural Selection.

Competition

• The most common interaction between species is competition.– One species will eventually become more efficient in

acquiring resources and food.• When two species compete for food in the same

niche, their niches overlap– Remember only one species can occupy a niche at a

time.• Competitive exclusion principle.

• What are the possible responses to niche overlap?

Predation

• All organisms need food to survive– Plants make their own– All other must eat

• Predation is the interaction between a feeder (predator) and what it eats (prey).

• Herbivores, Carnivores and Omnivores are all predators.

Predators

• Predator have two primary ways of capturing prey.– Pursuit and ambush

• Most predator have developed adaptations in either of these two areas.– Cheetahs - speed– Snowy Owl – camouflage

• Some predators use chemical warfare to paralyze it’s enemy.

Prey

• In answer to the Predator, many prey species have developed ways to defend themselves.– Physical barriers and strengths

• Spines, shells, thick bark• Faster escape and strong senses

– Camouflage• Cuttlefish

– Chemical Warfare• Poisonous to eat or create poison that they excrete when

aggravated.• Taste Bad

Prey

• Good rule of thumb– If it is small and strikingly beautiful, it’s

poisonous– If it is strikingly beautiful and easy to catch,

it’s DEADLY

• Other prey species use behavioral strategies to evade predators.– Mimicry

Fig. 5-2, p. 103

(h) When touched,snake caterpillar changesshape to look like head of snake.

(a) Span worm (b) Wandering leaf insect

(c) Bombardier beetle (d) Foul-tasting monarch butterfly

(f) Viceroy butterfly mimicsmonarch butterfly(e) Poison dart frog

(g) Hind wings of Io mothresemble eyes of a muchlarger animal.

Benefit of Predator-Prey Relationships

• Predation plays a major role in Natural Selection– Predators weed out the weak, sick, and dying

species.– Increases biodiversity

• Help keep grazing animals down and preserve the balance of an ecosystem.

Coevolution and Pred. v. Prey Relationships

• Coevolution is when two organisms evolve due to pressures exerted from each other.– It’s like an evolutionary arms race

• Constant struggle for survival create harder prey to catch and stronger predators to catch them.

Symbiosis

• Symbiosis are when two species live together in some form.

• Three Types of Sybiosis:– Parasitism– Commensalism– Mutualism

Parasitism

• Parasitism occurs when one species (the parasite) feeds on the body of, or the energy used by, another organism (the host), usually by living on or in the host.

• Common Characteristics of Parasites:– Smaller than the host– Rarely Kill the Host– Live directly on or in the Host

Parasitism: Tree with Parasitic Mistletoe, Trout with Blood-Sucking

Sea Lampreys

Commensalism

• Commensalism is when two species interact where one species benefits and the other is not harmed or benefits lightly.

Commensalism: Bromiliad Roots on Tree Trunk Without Harming Tree

Mutualism

• An Interaction where two species benefit from living together.– Nutrition– Protection– Hygiene– Health

Mutualism: Oxpeckers Clean Rhinoceros;

Anemones Protect and Feed Clownfish

Video: Otter feeding