6.5: Ecological Niches

Ecological niche

 The hypothesis that every species in an ecosystem fulfills a unique role 

• Unless all the dimensions of the niche are satisfied in an ecosystem of species will not be able to survive grow or reproduce

Competitive exclusion

•  essentially when fundamental niches of two species overlap one species is expected to exclude and it becomes a competition 

  • The outcompeted species does not have a realized Niche and will be competitively excluded from the whole ecosystem

ecological Theory

•  every species must have a realized Niche that differs from the realized niche of all other species if it is to survive in an ecosystem

 different organisms

1. Obligate anaerobes: 

2. Facultative anaerobes: 

3. Obligate Aerobes

Obligate anaerobes:

• Die from the presence of oxygen so have to live in anoxic environments

•  includes species of bacteria Archaea and protozoa 

Anoxic

•  lack of oxygen environments

Facultative anaerobes:

• Use oxygen if available so live in oxic or anoxic environments doesn't matter

Obligate Aerobes

•  require continuous oxygen supplies so only live in oxic environments

Oxic

• Environments with oxygen supply

Types of nutrition

• Holozoic nutrition

• Mixotrophic nutrition

• Saprotrophic nutrition

• Herbivores, carnivores, and omnivores

Holozoic nutrition

whole pieces of food are swallowed before being fully digested

1.  Ingestion;  take the food into the gut

2.  Digestion:  breaking large food molecules into smaller ones

3.  Absorption:  transport of digestive food across the plasma membrane and into Blood and Tissue

4.  Assimilation:  use digestive food to synthesize proteins and macromolecules

5.  Egestion:  avoiding undigested material AKA shitting

Mixotrophic nutrition

• Protists use both methods of heterotrophic and autotrophic nutrition

 Facultative mixotrophs

• can use either autotrophic or heterotrophic or both modes

 obligate mixotrophs:

•  have to use both autotrophic and heterotrophic modes of nutrition

Protist

• any eukaryotic organism that is not an animal plant or fungus 

Saprotrophic nutrition

• fungi use this

  •  Saprotrophs secrete digestive enzyme into dead organic matter and digest them externally

  • A lot of fungi are also known as decomposers because they break down carbon compounds and release their elements into the ecosystem 

Herbivores, carnivores, and omnivores

• Herbivores have side teeth to grind on plants, humans have a mix of sharp and molars for both, carnivores have sharp canines for meat

Herbivore insects

1.  beetles and other insects with jaw like mouth parts for chewing

2.  aphids and other insects with tubular mouthparts for piercing

plant resistance to herbivores

•  sharp spines or stings that risk injury

•  synthesize substances that are toxic to herbivores

  •  the substance are secondary metabolites

Prey adaptations to resist predation

•  Camouflage

•  Toxins

•  being in large groups 

Adoptions of plants to harvest light

• Plans can be for light so for us to just keep growing taller

•  trees have dominant leading shoots that grow rapidly to get light

• Lianas climb trees -- like vines