ecological niches Flashcards
(13 cards)
Ecological niche as the role of a species in an ecosystem (both biotic +abiotic elements - comp. for food, must specialize/zone of tolerance for abiotic factors)
Include the biotic and abiotic interactions that influence growth, survival and reproduction, including how a species obtains food.
An ecological niche is the role a species fulfills in an ecosystem.
Species usually show adaptations to the ecological niche which they occupy to avoid competition. This is also referred to as resource partitioning.
Differences between organisms that are obligate anaerobes, facultative anaerobes and obligate aerobes
Limit to the tolerance of these groups of organisms to the presence or absence of oxygen gas in their environment.
obligate anaerobes: organisms that are killed off in presence of oxygen - only occur in ANOXIC environemnents
facultative anaerobes: can survive with/without oxygen
obligate aerobes: need oxygen, so only live in OXIC enviro.
Photosynthesis as the mode of nutrition in plants, algae and several groups of photosynthetic prokaryotes
Details of different types of photosynthesis in prokaryotes are not required.
what are autotrophs?
Synthesize organic compounds (sugars, amino acids, fats) by using other sources of energy.
Holozoic nutrition in animals
Students should understand that all animals are heterotrophic and most but not all are consumers (holozoic). In holozoic nutrition food is ingested, digested internally, absorbed and assimilated.
steps (IDAAE)
- HETEROTROPHS: Obtain organic compounds by consuming other organism internally or externally.
- Holozoic: Complex food particles are taken in and broken down
The large food molecules must be broken down into smaller ones before they can be absorbed into the bloodstream and transported to cells in the body where they are needed.
Saprotrophic nutrition in some fungi and bacteria
Fungi and bacteria with this mode of heterotrophic nutrition can be referred to as decomposers.
Fungi are also called decomposers, because they break down dead organic matter and release important elements back into the ecosystem).
Saprotrophs digest food by secreting enzymes to break down organic compounds externally. The products of digestion are then absorbed.
Mixotrophic nutrition in some protists (unicellular eukaryote)
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.
This means that they can be autotrophs ( and carry out photosynthesis) and heterotrophs (consume other organism).
FM = Can be entirely autotrophic, entirely heterotrophic or use both modes.
OM = Must use both modes of nutrition. This is often the case if a type of nutrient cannot be synthesized by themselves.
Euglena gracilis is a single-celled eukaryotic algae that will photosynthesize (autotroph) in sufficient light, but can also ingest particles of food by phagocytosis, which it then digests. (heterotroph). It is facultative mixotroph.
Diversity of nutrition in archaea
Students should understand that archaea are one of the three domains (ABE) of life and appreciate that they include a variety of photosynthetic, chemosynthetic and heterotrophic organisms. Students are not required to name examples.
All living things can be categorised into three different domains: Archea, bacteria and eukaryotes. Archea are often adapted to life in extreme conditions such as hot springs, salt lakes or volcanic craters.
archaea can be photosynthetic, chemosynthetic and heterotrophic organisms
Relationship between dentition and the diet of omnivorous and herbivorous representative members of the family Hominidae (chimpanzees + humans)
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.
- Teeth of herbivores are large and flat to grind fibrous plant material.
- Omnivores tend to have a mix of different types of teeth to break down both meat and plants in their diet. The molars in the back of the mouth are often flat to crush seeds/sharper canines and incisors to tear tougher food like meat
Adaptations of herbivores for feeding on plants and of plants for resisting herbivory
Include piercing and chewing mouthparts of leaf-eating insects, spines, stings and toxic secondary compounds in seeds and leaves and metabolic adaptations for detoxifying these toxins in some animals.
Insects with jawlike mouthparts for biting off, chewing and ingesting pieces of leaf
Insects with tubular mouthparts for piercing leaves or stems to feed on the phloem sap (like aphids)
Plants develop a variety of adaptations for deterring herbivore attacks - like sharp spines and stings
Herbivores can also produce a number of phytotoxins made from secondary compounds - can cause nausea, cardiac problems or hallucinations when ingested.
Some ruminants have microbes in their guts which can detoxify the toxins, or proteins in the saliva which can destroy the toxin. The liver in some mammals can also neutralize some toxins.
Adaptations of predators for finding, catching and killing prey and of prey animals for resisting predation
Students should be able to suggest or identify examples of chemical, physical and behavioural adaptations in predators or prey.
Predators:
Physical - sharp incisors/canines to tear prey
Chemical - producing venom, paralyzing prey
Behavioral - ambushing/hunting in a pack
Prey:
Physical - camouflage, bright colours
Chemical - producing toxins
Behavioral - “schooling” behaviour
Adaptations of plant form for harvesting light (5)
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.
- Many plants such as herbs growing on the forest floor or shrub layer are shade tolerant and do not need a lot of sunlight.
- Lianas are vines that take root on the forest floor and use trees as a scaffold to grow up high into the canopy.
- epiphytes growing on branches of trees recieve lots of light
- strangler epiphytes = circle around tree, outgrow branches, shading out leaves of tree, causing tree to die, leaving peiphytes
Fundamental and realized niches
Students should appreciate that 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 when in competition with other species.
A species’ fundamental niche is the full range of environmental and social conditions under which it could potentially survive and reproduce, taking into account all the tolerance levels to abiotic and biotic factors.
The realized niche is the specific set of conditions under which it actually does survive in a given habitat or ecosystem, with the limitations of other species being present.
Competitive exclusion and the uniqueness of ecological niches
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.
If two species share a niche, this leads to inter-specific competition for resources. Inevitably, one species will have an advantage over the other with the less well-adapted species struggling more to survive and reproduce. It will lead to one of them either becoming extinct, or forced to migrate.
LEAD TO EXCLUSION OF SPECICES FROM ECOLOGICAL NICHE
