Organisms occupy niches.

A niche describes: the specific role of a species within an ecosystem.

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o Where they live (tree, burrow, cave, etc)

o How they use resources (food, nest building, etc)

o How they interact with others

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Relationships

​The interaction between organisms between overlapping niches can be described by five types of relationships.

1) Competition- organisms compete for resources.

a. Interspecific (between species) ex. Squirrel and owl competing for same tree nest.

b. Intraspecific (within species) ex. Two male walruses competing for mates.

Relationships

Predation - one organism hunts and kills another for food.

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Ex. Lion killing and eating a zebra.

Commensalism (+ o)

Relationship where one benefits and the other is not harmed.

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ex. The egret bird follows large animal herds, such as cows, to eat bugs stirred up in the grass when they walk.

Mutualism (+ +)

Relationship in which both organisms benefit.

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Ex. Pollinators and plants

Parasitism (+ -)

One organism steals resources from another. This harms, but does not immediately kill the other organism.

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Ex. Parasitic intestinal worms stealing the host organisms energy it consumed in the food. May begin to feed on host directly over time.

CLAIM- EVIDENCE- REASONING

For the following scenarios you will make a claim on the relationship type, provide evidence from the scenario, then connect the claim to the evidence describing your reasoning.

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Relationship types:

Competition

Predation

Commensalism

Mutualism

Parasitism​

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CLAIM- EVIDENCE- REASONING

Scenario – The burdock plant produces sticky burs that contain their seed. The sticky bur is designed to grasp onto the fur of passing animals, such as deer, and naturally fall off at a later time. This is a means of seed dispersal for the burdock plant.

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Claim: This is commensalism

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Evidence: burdock burs stick to fur. Animal is likely annoyed but not harmed.

Reasoning: Since the animal is not harmed, but the burdock benefits by having its seeds distributed, this would be commensalism.

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​Reasoning: Since the animal is not harmed, but the burdock benefits by having its seeds distributed, this would be commensalism.

Ecosystem

A community of organisms that interact with their environment.

All ecosystems are composed of biotic and abiotic factors.

Biotic - living

Abiotic - nonliving

Community

All the different species of organisms in the same area.

Population

Organisms of the same species in the same area.

Carbon

Carbon is the building block of life.

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All life on Earth, whether humans, plants, animals, or bacteria, is carbon-based.

Carbon

All biomolecules (carbohydrates, lipids, proteins, and nucleic acid) include carbon.

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Fuel (oil, coal, gasoline) is also carbon-based.

Scientists looking for life in space look for evidence of carbon.

All carbon on Earth goes through an endless cycle: the Carbon Cycle.

Carbon Cycle

There are four steps to the carbon cycle:

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1. Carbon enters the atmosphere as CO2.

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2. CO2 is absorbed through photosynthesis done by producers (plants).

Carbon Cycle

3. Animals consume plants, thereby taking in their carbon.

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4. When animals and plants die, their bodies decompose and their carbon is reabsorbed back into the atmosphere.

Nitrogen

The air you breathe is mostly made of nitrogen.

Nitrogen

Nitrogen is a part of two biomolecules: proteins and nucleic acids.

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All life on Earth requires nitrogen to survive.

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However, you cannot bring nitrogen into your body by breathing.

Nitrogen Cycle

Nitrogen also goes through an endless cycle:

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Bacteria 'fix' nitrogen (bring it in from the air).

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The bacteria convert the nitrogen to a form that plants can use.

Nitrogen Cycle

Plants bring nitrogen in through their roots.

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Animals eat the plants.

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When animals excrete waste, nitrogen returns to the soil or the atmosphere.