Theme B: B4 Ecosystems - B4.2 Ecological Niches Flashcards
(26 cards)
Ecological Niche
the unique role a species plays in an ecosystem
What niche an organism can fill depends on…
1) How it obtains food (specialisation reduces competition)
2) Zones of tolerance (range determines habitat)
3) how it interacts with other species in th ecosystem
obligate aerobes
All animals and plants since they require oxygen. Obligate (no choice) and aerobic (oxygen).
obligate anaerobes
Organisms that can only line in anoxic environments. obligate (no choice) and anaerobes (no oxgen).
e.g. bacteria that causes tetanus and methanogenic archae.
facultative anaerobes
Can live in oxic or anoxic environments facultative (choice) and anaerobes (no oxygen).
e.g. E. coli and yeast
what 3 groups of organisms use photosynthesis as their mode of nutrition?
3 groups of photosynthetic organisms
1) plants
2) algae
3) some bacteria
some cell biologists might call them autotrophs as they produce their own food, some ecologists might call them primary producers in terms of the role they place in an ecosystem
heterotrophs
organisms that must eat they’re food, they are consumers not producers.
holozoic nutrition
whole pieces of food are eaten and digested internally. most heterotrophs do this.
1) ingestion = eating something
2) digestion = chemical breakdown into smaller molecules
3) absorption = blood stream absorbs some of the smaller molecules
4) assimiliation = becoming part of the cells and tissues, hence the smaller molecules are used by our cells
5) egestion = the left over molecules that cannot be absorbed pass out of the anus as waste
mixotrophic
can gather nutrients and energy in autotrophic and heterotrophic ways. So they are consuming things as well as producing their own food.
obligate mixotrophs must use both methods.
facultative mixotrophs can use one method or the other depending on what is available in the environment. e.g euglena
decomposers
saprotrophs: decomposers that digest matter externally. e.g. some fungi and bacteria can spray diegstive enzymes onto things
detritivores: decomposers that digest matter internally.
what are the 3 ways in which archaea get energy/nutrition (ATP)
1) heterotrophic (from other organisms)
2) phototrophic (absorbing light energy)
3) chemotrophic (oxidising inorganic chemicals)
dentition
relates to teeth. one of the more visible adaptations of animals are ones that relate to their diet. teeth can be an indication of what they eat.
hominidae
family that includes humans, orangutans, chimpanzees and gorillas. the shape of the teeth are good indicators of what they eat. this can help us figure out the diet of extinct species.
herbivores and dentition
(plant eaters) large flat teeth for grinding
omnivores and dentition
(plant and animal eaters): micture of teeth including flat grinders and sharp ones (canines and incisors) for tearing meat.
adaptations of herbivorous insects that allow them to eat plants
they have two types of mechanisms relating to the structure of their mouth:
1) tube-shaped mouthpart that sucks the sap out of the plant phloem (aphids)
2) jawlike mouthparts fore biting/chewing leaves (beetles)
adaptations of plants for resisting herbivory
- spines/spikes
- stinging parts
- toxins
some herbivores have special adaptations for overcoming these. e.g. some aphids produce saliva that acts like a barrier and protets it from the plant toxin.
adaptations of predators for catching prey
- chemical: venom (cobra)
- physical: teeth/claws (lion)
- behavioral: ambush, hides under a rock and then ambushes its prey (moray eel)
adaptations of prey for resisting predation
- chemical: toxic (monarch butterflies)
- physical: camoflauge (walking stick)
- behavioural: schooling together (snapper)
how does the rate of development differ between the 3 types of adaptation?
behavioural is the fastest, then physical, and then chemical adaptations develop the slowest.
adaptations of plants for harvesting light
- trees grow very tall so the light is not blocked by other pants
- lianas (vines) grow through other tress and use them as support
- epiphytes (air plants) grow on tree trunks where there is more light
- some parasitic pants like strangler figs (strangler epiphytes) climb up the trunk and eventually outcompete the tree (their host) for light, which kills the host
- shade-tolerant shrubs grow on the forest floor where low levels of light are within their range of tolerance
fundamental niche
the range of tolerance of all of the abiotic factors for a species. This also includes parts of the niche where other species are more suited to the range of tolerance are likely to outcompete the organism and eat away at its role in its environment.
a very optimistic outlook, showing all the places that an organism could live.
realised niche
the actual niche that a species occupies because part of its range of tolerance is occupied by competitors.
more reaslitic outlook. its the fundamental niche minus all of the areas where that organism gets outcompeted by other species. its smaller than the fundamental niche.
competitive exclusion and the uniqueness of cological niches
one species will outcompete the other if their fundamental niches overlap. The species that outcompetes the other will be able to occupy its entire fundamental niche, whereas the outcompeted species will have a smaller realised niche. this leads to exclusion in parts of the range of tolerance.
if a species is outcompeted in all parts of its fundamental niche, it will be excluded from the entire ecosystem. every organism must have a realised niche to exist in an ecosystem. this has happened with climate change in particular, as it changes the range of tolerance by introducing different abiotic factors to ecosystems can possibly affect organisms whose niches aren’t overlapping yet but will be soon.
