This document discusses different types of symbiotic relationships between species: predation, parasitism, competition, mutualism, and commensalism. It provides examples for each type, such as predators and prey, parasites like ticks, competing species like Darwin's finches, mutualistic relationships like plants and pollinators, and commensal relationships like whales and barnacles. The document explains how these relationships can influence species' adaptations through mimicry, defenses, niche partitioning, and character displacement.

1. Symbiotic Relationships
Biology
Mrs. Neistadt

2. *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.

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

4. *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

5. *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

6. 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

7. *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

8. 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

9. *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.

10. 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

11. *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

12. 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

13. *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.

14. *Commensalism
• *Commensalism is a symbiotic
relationship where one organism benefits
and the second is neither harmed nor
helped.
• Ex: *Whales and Barnacles
– Barnacles have the benefit of moving through
waters attached to the whale
– The whale receives no benefit,
but is not harmed either

15. 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