B4.2 Ecological Niches

Ecological Niche- the role an organism plays in an ecosystem

• Biotic + abiotic factors in a niche affect

  • growth

  • survival

  • ability to reproduce

  • mode of nutrition

  • interactions with other species and own species

Aerobes and Anaerobes

Obligate Anaerobes- Must live in oxygen-free environment to survive- anaerobic respiration

Facultative anaerobes- Can survive with or without oxygen. Anaerobic in absence, aerobic in presence.

Obligate aerobes- Need oxygen to survive. Aerobic respiration.

Photosynthesis

Using light energy + Co2+ water to create glucose and oxygen

how plants, algae, and photosynthetic prokaryotes feed themselves.

• autotrophic- produce own food

Heterotrophic Nutrition

Can’t make own food, rely on other organisms for nutrition.

• animals

Holozoic Nutrition

form of heterotrophic nutrition

• ingest food → internally digest food→ absorb and assimilate nutrients of digested food

Mixotrophic Nutrition

• Carry out photosynthesis (autotroph) and feed on others (heterotroph)

  • Obligate mixotrophs, which require both autotrophic and heterotrophic modes of nutrition to survive.

  • Facultative mixotrophs, which can switch between the two modes of nutrition based on available resources. They can obtain all of their required nutrients using either autotrophic or heterotrophic modes of nutrition.

Saprotrophic

Heterotrophs that obtain nutrients through external digestion ie bacteria and fungi (decomposers) through the use of enzymes, nutrients are absorbed through assimilation

Archea- all produce ATP

• One of three domains of life- many live in extreme environments

• prokaryotes- lack a nucleus, no membrane-bound organelles

  • Phototrophs: Some archaea use light energy to produce ATP. This is a different process than photosynthesis and no oxygen is produced.

  • Chemolithotrophs: Some archaea oxidize inorganic compounds to produce ATP.  Different species of archaea use different inorganic compounds such as ammonia, nitrites and sulfur compounds.

  • Organotrophs: Some archaea oxidize organic compounds, such as sugars and fatty acids, to produce ATP.

Hominid - great ape family

Herbivores- mostly eat plants (have large flat teeth and strong jaws)

Omnivores- eat plants and animals (mix of flat molars and sharp teeth to eat meat)

Plant & Animal Adaptations

• chemicals (spicy) to deter herbivores from eating. Some birds and and humans ignore it.

• Tobacco plants produce toxin nicotine however caterpillars have evolved to detoxify the nicotine.

• Grass walls are hard to chew for animals but some adaptations include flat molars for grinding and continuously growing teeth to prevent wearing out.

Predator and Prey

Predators hunt and kill prey for food.

Predator adaptations

• sharp claws and talons

• powerful jaws and teeth

• speed and agility

• camouflage

• pack hunting and ambushing tactics

• Prey adaptations

  • swift and agile

  • camouflage

  • mimicry- mimic environment to avoid detection. Mimic dangerous sounds to predators ie poisonous or unpalatable

  • toxic chemicals- ie bright poison frogs

  • traveling in groups and swarms to confuse predators and make an attack difficult.

  • alarm calls

  • nocturnal or diurnal- adapt to avoid when predators are most active

Fundamental and Realized Niches

Fundamental- a niche that an organism could potentially occupy in the absence of competition from another species. Determined by adaptations and zones of tolerance

Realized Niche- a niche an organism occupies due to competition from other species.

Competitive Exclusion

Competitive exclusion states that no two species can occupy the same niche.

Two species cannot exist in the same niche, as one will be better adapted for the niche, and will outcompete and exclude the other species from the niche.

The less well-adapted species will either be eliminated from the niche, or restricted to a part of the niche.

Competitive exclusion leads to species occupying their realized niche.