Organisms and Their Relationships

Chapter 2

Section 1

Learning Targets

1. I can define and give examples of each level of ecological organization

2. I can contrast biotic and abiotic factors

3. I can explain the types of symbiosis4. I can describe the effects of

competition and predation

Ecology

• Scientists can gain valuable insight about the interactions between organisms and their environment.– Each organism, regardless of where it

lives, depends on nonliving factors found in its environment and on other organisms living in the same environment, for survival

Ecology

• EcologyEcology – the scientific discipline in which the relationships among living organisms as well as the interactions the organisms have with their environment are studied– Individuals who study ecology are

known as Ecologists

The Biosphere

• Because ecologists study organisms and their environments, their studies take place in the biosphere– Biosphere: the portion of Earth that

supports life– Bio means “life” and sphere means

“ball”

The Biosphere

• Biotic FactorsBiotic Factors – living factors in an organism’s environment– Interactions of organisms are important

for the health of all species in the same geographic location.

The Biosphere

• Abiotic Factors – nonliving factors in an organism's environment– Factors might include: temperature, air

or water currents, sunlight, soil type, rainfall, or available nutrients

– Organisms are adapted to surviving in the abiotic factors that are present in their natural environment. • If placed in a different environment, they

might die if they cannot adjust quickly

Levels of Organization

• The biosphere is too large and complex for most ecological studies. So, scientists have broken down the biosphere to make it easier to study.

• Levels of Organization:– Organism– Population– Biological Community– Ecosystem– Biome– Biosphere

Levels of Organization

1.1. OrganismOrganism: individual organisms themselves

2.2. PopulationPopulation: individual organism of a single species that share the same geographic location at the same time

3.3. Biological CommunityBiological Community: a group of interacting populations that occupy the same geographic area at the same time

Levels of Organization

4.4. EcosystemEcosystem: a biological community and all of the abiotic factors that affect it

5.5. BiomeBiome: a large group of ecosystems that share the same climate and have similar types of communities

6.6. BiosphereBiosphere: all of the biomes on earth combined

Ecosystem Interactions

• Interactions between organisms are important in an ecosystem.– Chances for survival of any one species

increases by using available resources in different ways

– HabitatHabitat – an area where an organism lives• Might be a single tree or a whole forest

– NicheNiche – the role or position that an organism has in its environment

Community Interactions

• Organisms that live together in a biological community constantly interact. – These interactions shape an

ecosystem

• Competition: occurs when more than one organism uses a resource at the same time– Ex: during a drought, water

is scarce and the strong organisms will compete with the weak organisms for water

Predation

• Some species get their food by eating other organisms– PredationPredation: the act of one organism

consuming another organism for food• Ex: Lion (predator) stalks

Zebra (prey)• Not all predators are

animals

Ex: Venus Fly Trap

Symbiotic Relationships

• Some species survive because of the relationships they have developed with other species.

• SymbiosisSymbiosis: The close relationship that exists when two or more species live together– There are 3 types: mutualism,

commensalism, and parasitism

Symbiotic Relationships

• MutualismMutualism: relationship between two or more organisms that live closely together and benefit from each other– Ex: Lichen

• CommensalismCommensalism: a relationship in which one organism benefits and the other organism is neither helped nor harmed

• ParasitismParasitism: one organism benefits at the expense of another organism

Symbiotic Relationships