B4.2 Ecological Niches

Include the biotic and abiotic interactions that influence growth, survival and reproduction, including how a species obtains food.

Define a niche.

State factors that determine the niche of a species.

Compare niche generalists and specialists.

Niche- unique functional position and roll every species fulfills within its environment

factors that determine the niche of a species: biotic and abiotic factors; physical and environmental conditions it requires (like temperature or terrain) and the interactions it has with other species (like predation or competition)

Generalists can eat a variety of foods and thrive in a range of habitats. Specialists, on the other hand, have a limited diet and stricter habitat requirements.

Limit to the tolerance of these groups of organisms to the presence or absence of oxygen gas in their

environment.

Compare the different oxygen requirements of obligate anaerobes, facultative anaerobes and obligate aerobes.

Details of different types of photosynthesis in prokaryotes are not required.

State the energy and carbon sources utilized in photosynthesis.

List three groups of photosynthetic autotrophs.

photosynthesis- energy from sunlight and carbon used to produce sugars

3 groups of photosynthetic autotrophs:

• plants

• eukaryotic algae

• sveralg groups of bacteria

Students should understand that all animals are heterotrophic. In holozoic nutrition food is ingested, digested internally, absorbed and assimilated.

Outline the acquisition of energy and matter by holozoic animals.

Distinguish between ingestion, digestion, absorption and assimilation.

holozoic nutrition- organic matter ingested then digested INTERNALLY

stages:

1. ingestion- taking food into gut

2. digestion- breaking large molecues down

3. absorption- transport of digested food into blood and tiss8ues

4. assimilation- syntehsize proteins and other macromolecules

5. egestion- voiding undigested material

feeding patterns:

• consumers- feed on living or recently killed organism

• scavengers- feed on dead and decaying carcasses (ex.hyenas)

• detrivores- feed on non-living organice matter(ex. bettles, crabs)

Euglena is a well-known freshwater example of a protist that is both autotrophic and heterotrophic, but many other mixotrophic species are part of oceanic plankton. Students should understand that some mixotrophs are obligate and others are facultative.

Outline the acquisition of energy and matter by mixotrophic protists.

State an example of a mixotrophic protist.

Distinguish between obligate and facultative mixotrophs.

Mixotrophic nutrition- may use sboth autotrophic & heterotrophi modes of nutrition; can either be obligate or facultive

ex. euglena gracilis (protist)

obligate mixotrophs- cannot grow unless utilze both autotrphic and heterotrophic modes vs

facltive mixotrophs- entirely autorphic, or entirely heterotrophic, or both

Fungi and bacteria with this mode of heterotrophic nutrition can be referred to as decomposers.

Outline the acquisition of energy and matter by saprotrophic organisms.

Compare location of digestion in saprotrophs and detritivore animals.

List two example saprotrophic organisms.

Explain why all saprotrophs are decomposers but not all decomposers are saprotrophs.

Saprotrophic nutrition- secret enzymes into dead organic matter and digest EXTERNALLY; decomposers

ex. fungi, bacteria, mold

Students should understand that archaea are one of the three domains of life and appreciate that they are

metabolically very diverse. Archaea species use either light, oxidation of inorganic chemicals or oxidation

of carbon compounds to provide energy for ATP production. Students are not required to name examples.

List the three domains of life.

Outline the characteristics of archaea.

Compare the energy source and carbon source in chemoautotrophs and photoautotrophs

3 domains of life: Bacteria, Archaea, and Eukarya

Archaea chrarateristics: unicellular, no nucleaus; metabolically very diverse.

main categories:

• chemoautotrophs - oxidation of inorganic chemicals

• photoautotrophs- absorption of light energy by pigments

• heterotrophic- oxidation of carbon compounds from other organism

Application of skills: Students should examine models or digital collections of skulls to infer diet from the anatomical features. Examples may include Homo sapiens (humans), Homo floresiensis and Paranthropus robustus.

List extinct and extant representatives of the Hominidae family of primates.

Outline the physiological, morphological and/or behavioral adaptations of mammalian teeth for different diet types.

Deduce the diet of an organism given dentition patterns

Application of skills: Students should examine models or digital collections of skulls to infer diet from the

anatomical features. Examples may include Homo sapiens (humans), Homo floresiensis and Paranthropus

robustus.

Dentition and diet:

teeth of herbivores- large and flat to grind down fibrous

omnivores- ix of diff types of teeth

humans- have flat molars to crush and grind food, sharper canine and incisors to tear tough food

For herbivore adaptations, include piercing and chewing mouthparts of leaf-eating insects. Plants resist herbivory using thorns and other physical structures. Plants also produce toxic secondary compounds in seeds and leaves. Some animals have metabolic adaptations for detoxifying these toxins.

Outline the physiological, morphological and/or behavioral adaptations of leaf eating insects for feeding on plants.

Outline the physiological, morphological and/or behavioral adaptations of plants for resisting herbivory.

adaptations of plants for resisting herbivory:

• spines and thorns;thick bark and waxy cuticles restrict ingestion

• produce toxic secondary compounds in seeds and leaves reduce feeding

adaptations of leaf eating insects for feeding on plants:

• specialised mouthparts- stylets piercing chewing plant matter

• metabolic adaptations for detoxifying these toxins

Students should be aware of chemical, physical and behavioral adaptations in predators and prey.

Outline the chemical, physical and/or behavioral adaptations of predators for finding, catching and killing prey.

Outline the chemical, physical and/or behavioral adaptations of prey animals for resisting predation.

adaptations of predators :

• swensory organs detect prey; sharp teeth and claws to pierce prey

• camoulflaged; streamlined shape to increases speed

• nueortixins and venoms to subdue prey

• may hunt in packs to capture prey; ambush streategies

adaptations of prey:

• tough exoskeletons and shells for protection

• camousflage or mimc predator; bright color for warning

• toxins and scents cause harm

• feign death, puff up, group together to avoud predation

Include examples from forest ecosystems to illustrate how plants in forests use different strategies to reach light sources, including trees that reach the canopy, lianas, epiphytes growing on branches of trees, strangler epiphytes, shade-tolerant shrubs and herbs growing on the forest floor.

adaptations of plant form for harvesting light:

• trees- dominant leaidng shoot that grows rapidly to be unsahded byothe r trees

• lianas- climbthroug other trees

• epiphytes- grow on trunks and branches to receive more light

• strangler epiphytes- limb up trunks of trees to shade out leaves of tree

• shade-tolerant shrub- absorb light reaching forest floor

Students should appreciate that a fundamental niche is the potential of a species based on adaptations and tolerance limits and that realized niche is the actual extent of a species niche when in competition with other species.

Distinguish between the fundamental and realized niche.

Fundamental niche- potential niche of a species based on adaptations and tolerance limits

vs realized niche- the actual extent of a species niche when in competition with other species.

Include elimination of one of the competing species or the restriction of both to a part of their fundamental niche as possible outcomes of competition between two species.

Explain competitive exclusion as a factor that can limit the distribution of a species in an ecosystem.

Explain why two species cannot survive indefinitely in the same habitat if their niches are identical.

State that organisms that can adapt to extreme niches encounter less competition and predation.

competitive exclusion- pne species uses resource smore eficiently driving other species to extinction

no two species can share exact same niche» otherwise lead rto direct comepetiion/struggle for survival

» organisms that can adapt to extreme niches encounter less competition and predation.