1.5 - Habitat, Niches, and Interactions

In a science experiment, equal-sized populations of two species of earthworms are placed in a terrarium filled with soil. Abiotic factors such as temperature and water supply are kept constant in the terrarium, as is food in the form of bread scraps. The population of each species is observed and counted each day.In agreement with the competitive exclusion principle, what is the MOST LIKELY outcome of the experiment over time? A. Only one population will thrive; the other population will decrease to zero. B. Both populations will reach the same size, which is the carrying capacity of the terrarium for earthworms. C. One population will be about twice the size of the other. D. Both populations will reach the same size, which is about half the carrying capacity of the terrarium for earthworms.

A

What is a niche?

A niche is the range of physical and biological conditions in which a species lives and the way the species obtains what it needs to survive and reproduce.

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

Mutualism

A relationship between two species in which both species benefit

Symbiosis

A relationship in which two different organisms live in close association with each other

How do competition shapes community?

By causing species to divide resources, competition helps determine the number and kinds of species in a community and the niche each species occupies.

Which is an example of herbivory affecting an ecosystem? A. Tall trees block the sunlight from reaching plants on the forest floor. B. Coyotes catch slow-moving rabbits, but not the faster rabbits. C. Deer eat the stems of plants without thorns, allowing plants with thorny stems to thrive. D. Fungi break down dead organic matter, which returns nutrients to the soil.

C

Yasmine states that tapeworms are common parasites of goats. Walter claims that the relationship between a tapeworm and goat should be classified as predator and prey. Which fact about tapeworms and goats is MOST useful for Yasmine to cite to refute Walter's claim? A. Tapeworms get their energy from food that they obtain from goats. B. Tapeworms benefit from their relationship with goats. C. Goats do not benefit from their relationship with tapeworms. D. Tapeworms live inside a goat's body in a close relationship with the goat.

D

Fungi, many birds, and a wide variety of insects all share the ________ of a tree in the forest.

Habitat

Part of the _______ of the fungi is to obtain energy from dead organic matter, such as dead wood.

Niche

The difference between niches and habitats

Niche: How it obtains food, mates and protection from predators. Habitats: It is where the organism finds food, shelter and mates.

What is a habitat?

Place where an organism lives

How do predation and herbivory shape communities?

Predators can affect the size of prey populations in a community and determine the places prey can live and feed. Herbivores can affect both the size and distribution of plant populations in a community and determine the places that certain plants can survive and grow.

What resources do animals compete for?

Space, food, water and mates

keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

Cattle egrets eat insects off the back of an elephant, which is an example of ________ because the cattle egrets benefit without either harming or helping the elephants.

commensalism

interspecific competition

competition between members of different species

intraspecific competition

competition between members of the same species

Certain bacteria live in the digestive tract of humans, and their relationship is an example of _______ because the bacteria help humans to break down the food they eat.

mutualism

The 3 types of symbiosis

mutualism, commensalism, parasitism

competitive exclusion principle

no two species can occupy the same niche in the same habitat at the same time

A flea and dog are an example of _________, because the flea irritates the dog's skin and feeds on its blood.

parasitism

Temperatures above 0°C and sufficient water in the environment help define the range of _______ for fungi.

tolerance

When does competition occur?

when organisms attempt to use the same limited ecological resource in the same place at the same time