EQ: What are the Relationships between organisms in an ecosystem?.

Types of ecological interactions competition predation Symbiosis mutualism Commensalism Parasitism

Habitat-area where an organism is best adapted to finding water, food, and enough space to live One habitat might contain hundreds or even thousands of species. A rotting log in a forest can be home to many species of insects, including termites that eat decaying wood and ants that feed on the termites. Other species that live on and under rotting log include millipedes, centipedes, spiders, and worms.

Niche – the specialized role a single organism has in a habitat

Competition – two species share a requirement for a limited resources  reduces fitness of one or both species

What are limiting Factors ? In the natural world, limiting factors like the availability of food, water, shelter and space can change animal and plant populations.(keeps a population from growing to large) Carrying Capacity--Carrying capacity refers to the maximum number of individuals who can be supported in a given area within natural resource limits

Competition Competition in an interaction between two organisms that are using the same limited resource. Competition can be within the same species or between different species Ex. Squirrels compete with other squirrels for nuts, but also compete with deer and chipmunks for nuts

Predation – one species feeds on another  enhances fitness of predator but reduces fitness of prey herbivory is not a form of Predation

Predator and Prey An organism’s niche includes how it avoids being eaten and how it finds or captures its food. Predators are consumers that capture and eat other consumers. The prey is the organism that is captured by the predator.

Predator and Prey The deer is being eaten by the python. It is prey. The python has captured and is eating the deer.

Predator and Prey Predator Prey

Prey Defenses Predation usually results in the evolution of defensive adaptations in prey. These can include: –Chemical defenses (toxins, poison, acrid sprays) –Behavior (living in groups, scouts, alarm calls) –Morphological features (spines, color, structures that allow you to run fast or detect predators), and other traits Photo Credit: Rhett A. mongabay.com Caterpillar with Venomous Spines

Predator/Prey Relationship The presence of predators usually increases the number of different species that can live in an ecosystem. Predators limit the size of prey populations. As a result, food and other resources(limiting factors) are less likely to become scarce, and competition between species is reduced.

Symbiosis-- 3 types Sym- together Bio- life/living Osis- Condition of

Symbiosis Not all relationships among organisms involve food. Many organisms live together and share resources in other ways. Any close relationship between species is called symbiosis. Video LINKVideo LINK

Symbiosis – two species live together  can include parasitism, mutualism, and commensalism

Mutualism – two species provide resources or services to each other  enhances fitness of both species.

Mutualism Bees travel from flower to flower to collect nectar –The flowers get pollinated and the bees get nectar to make honey

Mutualism There is a protozoan in the gut of a termite that helps it to digest the cellulose in the wood –The protozoan gets its food delivered and has a place to live and the termite has help in digestion

Commensalism – one species receives a benefit from another species  enhances fitness of one species; no effect on fitness of the other species

Commensalism Certain species of crab carry venomous sea urchins on their backs –Gives the crab protection from predators

Parasitism – one species feeds on another  enhances fitness of parasite but reduces fitness of host

Parasitism Leeches attach to their victims and inject an anti-coagulant to keep the blood from clotting –Leeches get a meal, and the organism loses blood and can get open wounds which can become infected.