Organism Relationships

Ms. KimH. Biology

What is an Ecological Niche?• Populations live along with other populations in a habitat with

a limited amount of resources. • A niche is how a population responds to the abundance of its

resources and enemies (those other organisms)

– Fundamental niche – all the resources that COULD be used by a population

– Realized niche – the ACTUAL resources used by a population

– Competitive Exclusion – when two species compete for the same resource, one will be better suited to the niche and the other will have to find another niche or go extinct

• Habitat = where an organism lives.

• Niche = how an organism lives.– Includes food, abiotic

factors, and behavior

How do Habitat and Niche Differ?

1. Available resources (ex. food, water, shelter)2. Activities of other organisms (ex. predators,

disease-causing parasites)3. Organism's own characteristics (ex. gestation

period, number of young produced, nurturing of young, migratory)

4. Time of day or year (ex. tides, seasons, nocturnal or diurnal)

5. Weather (ex. amount of rainfall, cyclone, drought)

Factors that Affect Populations

• Ecosystem: A system that includes all living organisms (biotic factors) in an area as well as its physical environment (abiotic factors) functioning together as a unit.

• Feeding• Symbiosis• Competition

Ecosystem Relationships

• We have discussed the feeding relationships of organisms, as we have identified producers, consumers, decomposers, and scavengers.

• As well as herbivores, carnivores, and omnivores.

• Another relationship is predator-prey relationship. – Population #s tied to each

other

Predator-Prey Relationships

Interactions Between Populations of Different Species

• Predation (+/–)—consumption of one organism by another– Predator eats prey

• Parasitism (+/–) —specialized predator (parasite) lives on/in its host, not killed immediately

• Endoparasitism—live inside host (tapeworms/viruses)

• Ectoparasitism—live on surface of host (mosquitoes/leeches)

• Herbivory (+/–)—herbivores consume plants

• Symbiotic Relationships - Close living associations

• Types of Symbiosis:– Commensalism - one organism is benefited and

the other is unharmed– Mutualism - both organisms benefit from the

association– Parasitism -the parasite benefits at the expense of

the host

Symbiotic Relationships

Symbiotic Relationships• “Sym” means same

3 Types of Symbiotic Interactions

Non-Beneficial1. Parasitism (+/–) —host

harmful Beneficial

2. Commensalism (+/0) —one partner benefits while not harming/helping the other

3. Mutualism (+/+) —both partners benefit

CompetitionInterspecific Intraspecific • Individuals of different

species compete for the same resource(s) such as food, water, or shelter in an ecosystem

• Individuals of the same species compete for the same resource(s) such as food, water, or shelter in an ecosystem

• Competition results in… – Lower birth rates, higher death rates (or both)– In evolutionary terms, an individual’s fitness is

lower

Competition

• How do organisms deal with low precipitation?

• How do organisms deal with hot temperatures?

• How do organisms deal with low temperature?

How do Organisms Adapt to their Biomes?

Animal Defenses Against Predators

• Behavioral defenses– Alarm cries– Distraction displays

• Coloration/shape (camouflage)

– Blend in with environment• Mechanical/chemical defenses

– Quills, spines, and other similar structures– Toxins—distasteful or poisonous

• Monarch butterfly stores toxin of milkweed as larvae

• Poisonous toads secrete toxin

Animal Defenses Against Predators (Con’t)

• Mimicry—prey resembles species that cannot be eaten

• Mimicry can be used to lure prey– Snapping turtle wriggles tongue like a

worm to attract and capture small fish

BOO!

Don’t eat me!

Adaptation - a characteristic of an organism that enables it to function more effectively or survive in it surroundings

5 Types of Adaptations◦ Structural - related to the structure of the organism ◦ Color - related to color ◦ Physiological - related to the organism's metabolism◦ Behavioral - related to behavior◦ Reproductive - related to courtship, mating or rearing of

young

Adaptations

Adaptation

Structural • The streamlined shape of

fish enables it to swim more quickly through water.

Color• Camouflage, warning

coloration of blue-ringed octopus, mimicry of butterfly wings with 'eye spot’

Adaptations

Physiological • During hibernation, bears

reduce their chemical processes

Behavioral• During the heat of the day

in the desert, lizards burrow into the sand to find a cooler place.

Reproduction• Peacocks fan their feathers to attract a mate.

Adaptations

+ Succession• "Ecological succession" is the observed

process of change in an ecological community over time

• Two types: 1) Primary Succession 2) Secondary Succession

+ Primary Succession• The development of an ecosystem in an area

that was previously uninhabited – Ex: Area aroundmelting glaciers– Ex: After a volcanoerupts

+ Secondary Succession• The re-establishment of a damaged ecosystem

in an area where the soil was left intact• Plants/other organisms start the re-growth – Ex: Fire damage

• What happens when new species are introduced?

• What are some examples?

• What happens when one organism disappears?

• What are some examples?

What happens when humans interfere?

Loss of habitat constitutes the greatest threat to the existence of native creatures and biodiversity.

The second worst threat is the biological invasion of alien plants and animals.

Non-native species come from somewhere else and they are not natural to the ecosystem they have been introduced to.

They may be harmless and beneficial or they can upset that balance and bring harm to the established plants and animals, and the whole ecosystem.

Non-native species

One of the worst aquatic weeds in the world.

Grow rapidly, doubling in 12 days and seeds can survive for 30 years.

Density may prevent sunlight and oxygen from reaching the water or may block waterways

Non-native species: Water Hyacinths: Good or Evil?

• In some ecosystems, the loss of one specie can have a profound effect on the ecosystem.

• This is called a Keystone Species.

• What are some examples?

• Examples:• Beavers• Sea Otters• Elephants• Wolves

Keystone Species