Species Interactions Section 2 1 Species Interactions Species

Species Interactions Section 2 -1

Species Interactions • Species within a community develop close interactions, known as symbiosis. – “Sym” means together – “Bio” means life – Symbiosis means “living together” and describes the close relationships developed between species. • Symbiotic relationships will always benefit at least one organism involved.

Species Interactions • There are 5 major types of symbiotic relationships: – Predation – Parasitism – Competition – Mutualism – Commensalism

Predation • Predation is a relationship where one organism captures and consumes another. – Predator – organism doing the capturing – Prey – organism being captured • A predator’s survival depends on its ability to catch its prey. – Ex: rattlesnake venom, spider web, etc. • A prey’s survival depends on its ability to avoid being caught. – Camouflage, mimicry, physical/chemical defenses

Prey Defenses • Mimicry – a defense where one organism resembles another that is dangerous or poisonous • There are two types of mimicry: – A harmless organism closely resembles a dangerous one • Known as Batesian mimicry • Predators learn to avoid both species • Ex: King snake and coral snake – Two harmful organisms resemble one another • Known as Mullerian mimicry • Added advantage to their already harmful adaptations • Ex: Bees and wasps have similar striping

Prey Defenses • Plants have also developed adaptations to protect them from predators. – Physical defenses make them difficult to eat • Ex: Spines, thorns, tough leaves – Can produce secondary compounds • Secondary compounds are synthesized from products of the plant’s metabolism • Usually poisonous, irritating, or bad-tasting • Ex: Poision ivy and poison oak

Parasitism • Parasitism – symbiotic relationship where one organism is harmed and the other is helped – Parasite feeds on the host organism – Unlike predation, it does not result in the immediate death of the host • Ex: tapeworms can live in human digestive tract for long periods of time

Parasitism • There are 2 different types of parasites: – Ectoparasites • External parasites – live on the outside of the host • Ex: ticks, fleas, mosquitoes – Endoparasites • Internal parasites – live inside the host’s body • Ex: bacteria, protists, tapeworms

Competition • Competition – the use of the same limited resource by two or more species in the same place at the same time – Resource = anything necessity of life (water, nutrients, light, food, or space) • Competition may cause the development of different niches or physical characteristics.

Competition • Competitive Exclusion Principle – No two species can occupy the same niche in the same habitat at the same time – Ex: Paramecia • Two species of paramecia will thrive separately, but when put together, one species is eliminated

Competition • Organisms may develop physical differences because of competition for resources. • Character Displacement – evolution of anatomical differences that reduces competition – Happens most where ranges of competitors overlap – Ex: Darwin’s finches • Species found in separate locations have the same beak size • The same species found together have different beak sizes – allows them to feed on different seeds and reduces competition

Competition • Organisms may develop differences in niches because of competition for resources. • Resource Partitioning – species coexist by using only part of the available resources – Ex: some birds eat the same insects, but hunt for them in different places

Mutualism • Mutualism is a symbiotic relationship where both organisms are helped in some way. • Ex: Plants and their pollinators – Pollinators feed on the plants and pollen gets stuck to them. – Pollen is deposited on the next plant, allowing the plants to reproduce sexually.

Commensalism • Commensalism is a symbiotic relationship where one organism benefits and the second is neither harmed nor helped. • Ex: Clownfish and sea anemone – The clownfish uses the anemone as shelter – The anemone receives no benefit, but is not harmed either – animation

Name the Symbiotic Relationship… • A eagle hunting a mouse. – Predation • A tick feeds on the blood of its host and may carry disease – Parasitism • The flower lives on a tree and absorbs the water from runoff and the tree is unaffected. – Commensalism • Two different types of finches feeding on seeds. – Competition • An ant protects a caterpillar from predators and the caterpillar produces a sweet liquid for it to drink. – Mutualism