Ecological Niches

Niche partitioning

When, through natural selection, species show adaptations to the ecological niche they occupy in order to avoid interspecific competition.

Fundamental niche

The full range of environments and social conditions under which a species could potentially survive and reproduce, taking into account the tolerance of abiotic and biotic factors.

Realized niche

The specific set of conditions under which a species actually survives in a given habitat or ecosystem.

Explain foundamental and realized niche with an example.

• When Paramecium aurelia and Paramecium caudatum are grown in separate environments they both strive. When they are grown in the same environment P. aurelia outcompetes P. caudatum.

• In nature it’s rare that two species occupy the same identical niches, however, the larger area they share the more interspecific competition.

Competitive exclusion

No two species can occupy the same niche, as the competition between them would cause one to strive and drive the other out.

Specialist species

Species adapted to narrow habitats, limited food resources or other specific environmental conditions.

Generalist species

Species adapted to a wide veriety of habitats, food resources and environmental conditions.

Ecological niche

The position and role of a species within a habitat

Obligate anaerobes

• Only anaerobic growth, so dies in presence of oxygen

• e.g. Saccharomyces

Facultative anaerobes

• Both aerobic and anaerobic growth, although growth is optimal with oxygen

• e.g. Clostridium tetani

Obligate aerobes

• Only aerobic growth, dies in the absence of oxygen

• e.g. All animal and plant cells

Autrophic organisms

Organisms that can produce their own chemical energy from sunlight, inorganic compounds and other energy sources

Heterotrophobic organisms

Organisms that cannot produce their own food, so must ingest nutrients from other organic sources.

Holozoic nutrition

Organisms that consume food through the processes of ingesting, digesting and assimilating nutrients.

Mixotrophic organisms

An organism that can use a mix of different sources of energy and carbon. They can be autrophs and heterotrophs

Saprotrophic nutrition

A method by which organisms feed on nonliving organic matter by secreting digestive enzymes and absorbing the products.

How are living organisms classified

• Bacteria

• Archea

• Eukarya

Archaea

• Cell membrane has branched fatty acids with unique bonding to the glycerol

• Cell wall is made of polysaccharides

• Larger and more complex genome compared to bacteria

• Don’t cause disease

• Are extremophiles

Chemoautotrophs

Organisms that derive energy from the oxidation of inorganic compounds via chemosynthesis.

Photoautotrophs

Organisms that make their own energy using light and carbon dioxide via the process of phototsynthesis.

Hominins

Refers to all modern and extinct humans and their immediate ancestors.

Hominids

A primate of the family Hominidae that includes humans and their fossil ancestors including some of the great apes.

Facultative mixotroph

Can utilise either or both autrotroph and heterotroph modes of nutrition depending on the conditions

Obligate mixotroph

Must use both modes of nutrition.

Example of mixotroph

Euglena

What are saprotrophs also reffered to as?

Decomposers = broad term
Detrivors = Organisms that help areate the soil and break down dead organic matter.

Detrivores

• Ingest dead organic matter and digestes it internally

• e.g. animals: crabs, snails, worms, woodlice

Saprotrophs

• They secrete extracellular digestive enzymes to digest it externally and then absorb the chemically digested products

• e.g. funghi and bacteria

Photoautotrophic archaea

• Do a form of photosynthesis different from the classical

• Use different pigments than chlorophyll

• Don’t generate oxygen

• Use light-activated ion pumps rather than electron transport chain.

Chemoautotrophic archaea

• Can use inorganic energy sources such as hydrogen sulfide, ferrour iron, molecular hydrogen and ammonia to produce energy.

• Oldest form of acquisition on Earth

Teeth types

• Incisors: Cut food when bitten

• Canines: Tier food like meat and crunchy vegetables.

• Premolars: Tier, crush and grind food into small spieces

• Molars: Do 90% of the chewing, crushing and grinding food

Herbivorous mammals teeth

• Incisors are long and flat to cut plants like scizzors.

• Back molars are large and flat to macerate plant through sidewasy grinding.

• Space between incisors and molars is diastema, which allows the tongue to move the food from the front to the back.

• Eyes are far apart for better field of view

Adaptations of plants to avoid herbivory

• Some plants produce phytochemicals, which are toxic secondary compound which hurt the eaters.

• Structural adaptations: thick rigid leaves that are hard to chew, large thorns, microscopic thorns

Adaptations of predators to kill prey

• Physical: use speed and agility to catch preys, have digestive system that is able to digest preys, increased eyesight…

• Chemical: some predators release toxins that interfere with biological processes.

• Beheavioural: Hunting together

Adaptations of prey to resist predation

• Physical: camouflage, speed, spines, bright colours to indicate toxins.

• Chemical: preys can release chemical to harm the predators.

• Work together to look like a large organism

Adaptations of plants to harvest light

• Lianas have arial roots that can climb the tallest trees of the forest

• Epiphytes aren’t rooted on the ground and grow entirely on branches of other plants.

Ingestion

The process of taking food into the body

Digestion

The breakdown of food into smaller components that can be absorbed by the body

Absorption

Uptake of the products of digestion

Assimilation

The process by which the absorbed nutrients are used by the body for energy