Functions of an ecosystem Flashcards
What are the functions of an ecosystem?
- Ecological Succession/Ecosystem Development
- Homeostasis (cybernetic)/Feedback ctrl mechanism
- Energy flow through food chain
- Nutrient Recycling (Geochemical cycles)
Ecological Succession?
Process by which communities of plants or animals in an area are replaced by another due to large scale changes or destruction.
Stages of ecological succession
- Pioneer community
- Successional stages or Seres
- Climax community
Succession occur fastest in which part of a continent?
In the middle of the continent. It is because the seeds of plants belonging to different seres would reach much faster.
Primary Succession?
Succession where no community has existed before. Pioneer species generally include lichens, mosses and algae.
Autotrophic vs Heterotrophic Succession?
Succession in which green plants are greater in quantity is called autotrophic succession & one in which heterotrophs are greater in number are called heterotrophic succession.
Secondary Succession?
The sequential development of biotic communities after the complete or partial destruction of existing community.
Primary vs Secondary Succession
Unlike Primary, Secondary succession happens at a place where the soil is already formed at the site, hence it is relatively faster.
Autogenic & Allogenic Succession?
When living inhabitants of that community brings about change it is called autogenic. When external forces bring change, it is called Allogenic.
Autogenic is driven by biotic components while allogenic is driven by abiotic.
Grasses are not succeeded by trees in grassland ecosystems, why?
Grasses dry up and causes fire which destroy other plant species and seeds - autogenic succession. Also scanty rainfall do not support growth of trees. Grasses are the climax community.
What is xerarch & hydrarch?
If succession happens where moisture content is low, eg: Rock it is called xerarch. If the same happens in a water body it’s called hydrarch
What is mesophytic habitat?
Both hydrarch & xerarch convert land to mesic where it is not too wet or dry, hence xerophytic habitat gets converted into mesophytic habitat.
Succession in water?
Pioneer species - Phytoplankton followed by Angiosperms, hydrophytes, sedges, grasses and finally trees. Water gets converted into land. Whether land or water both has similar climax community - mesic
Homeostasis?
Tendency of an ecosystem to resist change. It has the capability of self-regulation of species structure & functional processes to maintain equilibrium.
Regulators vs Conformers
Regulators maintain constant internal environmental - Eg: Mammals (Temp). Conformers conform to the external environment Eg: Fish (Osmotic pressure)
Why very small animals are rarely found in polar regions?
Very small animals have large surface area, they lose heat fast. Hence, they have to generate heat through metabolism for thermoregulation. It is very energy expensive.
Which national park sees migration of birds from Siberia during winter?
Keoladeo National Park - Bharatpur, Rajasthan
Some examples of suspend as a means of homeostasis?
- Thick walled-spores in algae, fungi & lower plants
- In higher plants vegetative reproductive structures, serve the means
- Polar bears - hibernation
- Snails & Fishes - Aestivation
- Zooplankton - diapause
Grazing food chain?
Consumers that start the food chain utilizing plant/plant part as food constitute grazing food chain. It can be terrestrial/aquatic.
Detritus food chain?
Consumers that start the food chain utilizing dead/decaying matter as food constitute grazing food chain. It can be terrestrial/aquatic.
Through which food chain does major energy flow?
In aquatic ecosystems, major energy flow through grazing food chain while in terrestrial ecosystems its through detritus.
All Protists are decomposers. (T/F)
False. Protists are unicellular organisms. Some protists like paramecium & euglena are not decomposers while others like slime molds are.
What is catabolism?
Fungi and Algae convert detritus to inorganic substances
What is humification?
Humification leads to formation of dark coloured amorphous substance called humus. It’s in colloidal form and reservoir of nutrients
Mineralisation?
Some microbes further decompose humus and release inorganic compounds by the process of mineralisation
Which phylum in animal kingdom contain detritivores?
- Porifera - Sponges are important detritivores in marine ecosystems.
- Annelida - Earthworms, leaches, polychaetas
- Arthropoda - ants, termites, millipedes, woodlice, crabs, and shrimp
- Mollusca - Snails, Slug, Clams, Oysters.
- Echinodermata - Starfish, Sea urchin, Sand dollar, Sea cucumber
Amensalism?
One is harmed, while other is unaffected.
1. Antibiosis - Bread mould fungi Pencillium
2. Competition - Large tree inhibit growth of small tree by giving shade but no effect on larger tree
commensalism?
One is benefitted, no impact on the other.
Eg - Suckerfish attaches to shark, tree & epiphytic plant.
