Environment Ecology Ecosystems Flashcards
(88 cards)
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Environment
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An environment is a natural component in which biotic and abiotic factors interact among themselves and with each other.
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Abiotic components include
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climate, weather, humus, natural phenomenon like lightning, etc.
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Biotic components include
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living organisms, dead and decaying matter, bones, fossils, etc. Biotic is not the same as organic.
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Habitat
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Habitat is the physical environment in which an organism lives (address of an organism). Many habitats together make up the environment.
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Organic compounds and Inorganic compounds
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Organic compounds- 1. having at least one carbon-hydrogen bond 2. those obtained directly or indirectly from plants and animals. Eg. biomolecules like carbohydrates, lipids, proteins, and nucleic acids
Inorganic compounds- 1. (typically lacking carbon-hydrogen (C-H) bonds). 2. The compounds obtained from minerals are known as inorganic compounds
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Ecosystem
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An ecosystem can be visualized as a functional unit of nature, where living organisms interact among themselves and with the surrounding physical environment. An ecosystem can be of any size but usually encompasses specific species. E.g., Aquatic Ecosystem.
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Classification of Ecosystems
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terrestrial and aquatic ecosystems.
Forest, grassland, and desert are some examples of terrestrial ecosystems
Pond, lake, wetland, river and estuary are some examples of aquatic ecosystems.
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Ecosystem vs Environment
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An ecosystem (has life in it) is a functional unit of nature or environment. An environment (may or may not have life) is a group of ecosystems.
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Ecology
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is the study of interactions between organisms, and organisms and the surroundings in an ecosystem.
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Ecological community
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A community of organisms interacting with one another
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Biodiversity
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The flora and fauna of a geographical area
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Biosphere
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The biosphere is the biological component (supporting life) of the earth which includes the lithosphere, hydrosphere, and atmosphere. It consists of all living organisms, together with the dead organic matter produced by them.
The biosphere is absent at extremes of the North and South poles, the highest mountains, and the deepest oceans since existing hostile conditions do not support life. Occasionally, spores of fungi and bacteria do occur at a great height beyond 8,000 metres, but they are metabolically inactive and hence represent only dormant life.
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limiting factors
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That limit the range of an organism.
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Eurythermal
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organisms can tolerate and thrive in a wide range of temperatures
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Stenothermal
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organisms can tolerate and thrive in a small range of temperatures
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Stenohaline
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Organisms that tolerate a low range of salinities
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Euryhaline
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Organisms that tolerate a wide range of salinities
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pH
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pH is a measure of the acidity or alkalinity (basicity) of a solution, on a scale from 0 to 14.
A high pH (above 7) indicates that the solution is alkaline or basic.
pH 7 is considered neutral, meaning the solution is neither acidic nor alkaline.
A low pH (below 7) indicates that the solution is acidic.
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Fast growing forests
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Abundant sunlight, nutrition, resources
Tropical Rainforests
Temperate Rainforests
Mangrove Forests
Planted Commercial Forests
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Biotic Components
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Autotrophs and Heterotrophs
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Q
The rainforest soil is deficient in nutrients. Why?
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Rainforest ⇒ It rains almost every day ⇒ The topsoil is continuously washed away ⇒ nutrients are also washed away (leaching of nutrients) ⇒ very little fertility remains in topsoil ⇒ most of the seeds don’t germinate for years. But the layer below the topsoil is very fertile. Thus, plants proliferate once their roots reach the sub-soil and if they receive enough sunlight.
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Slow growing forests
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harsh climatic conditions, poor soil quality, short growing seasons, and limited resource availability. Boreal forests, Tundra and alpine forests, Montane cloud forests, Mediterranean forests etc.
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Propagules and in a rainforest
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Propagules are any part of a plant that can give rise to a new plant. This includes Seeds,, Vegetative structures like cuttings, runners, suckers, tubers, and spores.
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Autotrophs
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Primary producers (self-nourishing) are green plants, certain bacteria and cyanobacteria/blue-green algae that carry out photosynthesis. In the aquatic ecosystem, microscopic algae (plankton) are the primary producers.
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Macro and Micro Consumers
Macro Consumers-
Primary consumers that feed mainly on plants. E.g., sheep, rabbit, etc.
Secondary consumers feed on primary consumers. E.g., wolves, dogs, snakes, etc.
Tertiary Consumers feed on both primary and secondary consumers. E.g., lions (can eat wolves), snakes etc.
Micro Consumers-
Phagotrophs are tiny organisms that feed by ingesting organic matter or organisms.
Osmotrophs are organisms that obtain their nutrients by the uptake of dissolved organic matter from the ambient medium through osmosis (movement of a solvent through a semipermeable membrane).
Saprotrophs/decomposers/detrivores are bacteria and fungi (e.g., mushrooms) which obtain energy and nutrients from dead organic substances (detritus).
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Heterotrophs
Consumers (other nourishing) are incapable of producing their own food. They depend on organic food derived from plants, animals, or both. Consumers can be divided into two broad groups, namely micro and macro consumers.
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Dieback
Dieback refers to the progressive dying, usually backwards from the tip of any portion of the plant. This is one of the adaptive mechanisms to avoid adverse conditions like drought. In this mechanism, the root remains alive for years together, but the shoots die. E.g. sal, red sanders, silk-cotton tree etc.
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An organism
is an individual living being that can act or function independently.
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Species
are a group of living organisms consisting of similar individuals capable of exchanging genes (interbreeding).
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Community
Communities are named after the dominant plant form. Major Communities: These are large-sized and relatively independent. They depend only on the sun’s energy from outside. E.g., Tropical evergreen forests. Minor Communities: These depend on neighbouring communities and are often called societies. They are secondary aggregations within a major community. E.g., A mat of lichen on a cow dung pad.
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Population
The population is a community of interbreeding organisms (same species) occupying a defined area during a specific time.
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Niche
unique functional role and position of a species in its habitat or ecosystem. A niche is unique for a species, while many species share the habitat. No two species in a habitat can
have the same niche.
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Ecotone
zone of transition between two ecosystems. E.g., grassland (between forest and desert), estuarine (between fresh water and saltwater), mangrove forests (between marine and terrestrial ecosystems). have far greater productivity than natural ecosystems. This is called the edge effect, and the species which occur primarily or most abundantly in this zone are known as edge species.
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Home Range
A home range is an area where an animal lives and moves on a daily or periodic basis (a little bigger than habitat.
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A biome
a large, distinct ecological community of plants, animals, and other organisms that is shaped by the climate and environmental conditions of a particular area.
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Ecocline
is a zone of gradual but continuous change from one ecosystem to another when there is no sharp boundary between the two in terms of species composition.
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An adaptation
is the appearance/behaviour/structure/mode of life of an organism that allows it to survive in a particular environment.
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Morphological adaptation examples
1. Many desert plants have thick cuticles on their leaf surfaces and have their stomata arranged in deep pits to minimize water loss through transpiration. Some desert plants like Opuntia have no leaves – they are reduced to spines (to reduce transpiration), and the photosynthetic function is taken over by the flattened stems (few leaves mean less area is available for transpiration).
2. Mammals from colder climates generally have shorter ears and limbs to minimise heat loss. (This is called Allen’s Rule.) Guess why an elephant has enormous ears? Because elephants don’t sweat. They use their flapping ears to lose heat and keep the rest of the body cool.
3. A hyperthermophile is an organism that thrives in extremely hot environments (60 °C). E.g., Archaebacteria flourish in hot springs and deep-sea hydrothermal vents.
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Archaebacteria (Archaea), Eubacteria
Archaebacteria (ancient bacteria), eubacteria (true bacteria) belong to the kingdom Monera, which contains the least organised unicellular prokaryotic (genetic material is not stored within a membrane-bound nucleus) microorganisms on earth. Archaebacteria can survive in extreme environmental conditions. A special protein helps these organisms form a protective, lipid-linked cellular membrane – a key to withstanding extremely highly salty areas (halophiles), hot springs and acidic habitats (thermoacidophiles).
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Variation and mutation
mutation is a genetic change that introduces new variation, and variation is the differences in traits that arise within a population, which can be influenced by mutations, recombination, and environmental factors.
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Evolution
Evolution is the change which gives rise to new species. It happens to make the organism better suitable to the present environment. Evolution involves the processes of natural selection, adaptation, variation etc. Charles Darwin and Alfred Wallace propounded.
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Adaptive radiation
process in which organisms diversify from an ancestral species into many new forms when the environment creates new challenges or opens new environmental niches.
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Speciation and types
Speciation is the process by which new species are formed, and evolution is the mechanism by which speciation is brought about. Allopatric due to geographic isolation and sympatric speciation, no physical barriers prevent mating. However, a new species, perhaps based on a different food source or characteristic, seems to develop spontaneously.
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Extinction
occurs when species cannot evolve fast enough to cope with the changing environment. Currently, the 6th Mass Extinction (Anthropogenic Extinction – human-induced) is in progress.
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Recombination
sexually reproducing population, meiosis and fertilization produce a new combination of genes every generation, which is termed recombination.
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The largest mass extinction event in earth’s history
Permian-Triassic Extinction (250 million years ago)
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Acclimatization
Small changes that take place in the body of a single organism over short periods to overcome minor problems due to changes in the surroundings is called acclimatisation
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The extinction of other vertebrate species on land allowed dinosaurs to flourish.
Triassic-Jurassic Extinction (210 million years ago)
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Which mass extinction wiped out dinosaurs and some 50 per cent of plants and animals.
Cretaceous-Tertiary Extinction (65 million years ago)
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Anthropocene
(since the agricultural revolution 12,000–15,000 years ago to the present) is a proposed geological epoch dating from the commencement of significant human impact on Earth’s geology and ecosystems, including, but not limited to, anthropogenic climate change.
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Ecological Succession
process by which communities of plant and animal species in an area are replaced or changed into another over a period of time is known as ecological succession.
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The function of an ecosystem includes:
1. Ecological succession or ecosystem development
2. Homeostasis (cybernetic)/feedback control mechanisms
3. Energy flow through the food chain
4. Nutrient cycling (biogeochemical cycles)
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Stages in Ecological Succession
The first plant to colonise an area is called the pioneer community. The final stage of succession is called the climax community, which is more complex and long-lasting. The stages leading to the climax community are called successional stages or seres. Succession would occur faster in an area existing in the middle of the large continent. This is because here seeds of plants belonging to the different seres would reach much faster.
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Autogenic and Allogenic Succession
When living inhabitants of that community itself bring about succession, the process is called autogenic succession, while change brought about by outside forces is known as allogenic succession.
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Ferns
are vascular plants that typically require some form of soil or substrate to anchor their roots and obtain nutrients.
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Lichens
Lichen are plant-like organisms that consist of a symbiotic association of algae and fungi. Fungi provide shelter, water and minerals to the algae and, in return, the alga provides food. Lichens can absorb water and nutrients directly from the air, making them capable of surviving in nutrient-poor conditions.
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Mosses
are non-vascular plants that can grow in a variety of environments, including surfaces without soil, such as rocks, tree trunks, or bare ground. They can absorb water and nutrients directly from the atmosphere and do not require soil to grow, though they thrive in moist, shaded conditions.
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Mushrooms
are the fruiting bodies of fungi, and while fungi can grow on decaying organic matter or on rocks, mushrooms themselves usually require a substrate with some form of organic material (like dead leaves, wood, or soil) to grow. Fungi may colonize surfaces without soil but typically need a nutrient base.
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In grasslands, trees do not replace grasses during ecological succession primarily due to
Water limitations: Grasslands typically have a semi-arid climate with insufficient rainfall to support the growth of trees. Grasses are adapted to survive in these conditions.
Fire: Grasslands are prone to frequent fires, which prevent the establishment and growth of trees. Fires kill young trees or saplings, while grasses are more fire-resistant due to their ability to grow back quickly after being burned. This creates a cycle that maintains the dominance of grasses.
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Homeostasis
is the maintenance of stable equilibrium, especially through physiological (bodily) functions. Some organisms can maintain homeostasis by physiological means (sweating to cool the body, increase in metabolism to keep the body warm, etc.), and sometimes by behavioural means (animals migrating to under tree shade). All birds and mammals and a very few lower vertebrate and invertebrate species are indeed capable of such regulation
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Conform
An overwhelming majority of animals and nearly all plants cannot maintain a constant internal environment. Their body temperature changes with the ambient temperature. These animals and plants are simply conformers. This is the main reason why very small animals are rarely found in polar regions.
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Suspend
To tide over unfavorable circumstances. In bacteria, fungi and lower plants, various kinds of thick-walled spores are formed, hibernation, Some snails and fish go into aestivation, zooplankton species in lakes and ponds are known to enter diapause, a stage of suspended development.
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Homeostasis in Ecosystem
Homeostasis is the tendency for a biological system to resist changes.
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A trophic level
(trophe means nourishment) represents energy flow in an ecosystem. The trophic level of an organism is the position it occupies in a food chain. Energy level decreases from the first trophic level upwards due to loss of energy in the form of heat at each trophic level. This energy loss at each trophic level is quite significant. Hence there are usually not more than four-five trophic levels
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Food chain and types
A food chain is a linear sequence that shows the flow of energy and nutrients from one organism to another in an ecosystem. Types of food chains: 1) Grazing food chain and 2) Detritus food chain. The consumers which start the food chain, utilizing the plant/plant part as their food, constitute the grazing food chain. Detritus food chain starts from organic matter of dead and decaying animal and plant bodies from the grazing food chain.
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Phytoplankton vs zooplankton
Phytoplankton are producers that generate their own food through photosynthesis, forming the base of the aquatic food web. Eg. diatoms, coccolithophores, Cyanobacteria (Bluegreen algae) – Synechococcus, Prochlorococcus, Nostoc, spirogyra, etc. and Dinoflagellates
Zooplankton are consumers that feed on phytoplankton, serving as an important food source for larger organisms in the aquatic ecosystem.
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Fungi, bacteria, virus wrt decomposition
Fungi and Bacteria are decomposers. They break down organic matter into simple inorganic substances.
Virus represents dormant life. They are metabolically inactive if they are outside a host body. They are not decomposers. They invade host cells and use their nucleus (DNA machinery) to carry out their life processes.
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Humus
Humification leads to the accumulation of a dark-coloured amorphous (formless) substance called humus that is highly resistant to microbial action and undergoes decomposition at a very slow rate
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Name some detritivores
Earthworms
Millipedes
Woodlice
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What do jellyfish and seahorses feed on
carnivores, primarily feeding on plankton, small fish, and other marine organisms, not dead organic matter.
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Name some aquatic detritivores
Crabs
Shrimp
Catfish
Benthic worms
Snails
Isopods like woodlice or water fleas
Corals
Scavenging fish (e.g., tilapia, carps, bass)
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Food Web
Multiple interlinked food chains make a food web. A food web represents all the possible energy flow pathways in an ecosystem.
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Amensalism
One species is inhibited, while the other species is unaffected. Eg. fungi Penicillium produces penicillin — an antibiotic substance — which inhibits the growth of a variety of bacteria.
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Commensalism
One species (the commensal) benefits, while the other species (the host) is neither harmed nor inhibited. Eg. relationship between trees and epiphytic plants.
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Mutualism
Interaction is favourable to both species. Very intimate form called symbiosis interacting species can no longer live without each other as they depend totally on each other to survive.
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Crustaceans
form a large group of arthropods which includes crabs, lobsters, crayfish, shrimp, krill, etc.
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Copepods
are a group of small crustaceans found in nearly every freshwater and saltwater habitat.
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Foraminifera
unicellular zooplankton
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Cnidarians
are soft-bodied, radially symmetrical animals that live in aquatic environments. They have two cell layers, a jelly-like middle layer called the mesoglea, and a single opening for both ingestion and excretion. Cnidarians are also known for their cnidocytes. Some examples of cnidarians include: Jellyfish, Sea, anemones, Corals, Hydras, Portuguese men-of-war, Sea fans pens whips. Cnidarians have a mutualistic relationship with dinoflagellate algae.
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Protozoa
are unicellular, eukaryotic, heterotrophic organisms. They are either free-living or parasites.
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Ecological Pyramids
The pyramidal representation of trophic levels. The ecological pyramids are of three categories: 1) Pyramid of numbers,
2) Pyramid of biomass, and
3) Pyramid of energy or productivity.
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Pyramid of Numbers
Upright- the number of individuals decreases with each higher trophic level. This type of pyramid can be seen in the grassland ecosystem and pond ecosystem.
Inverted- In this pyramid, the number of individuals increases with each higher trophic level.. E.g., Tree ecosystem.
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Pyramid of Biomass
Upright- For most terrestrial ecosystems, the pyramid of biomass has a large base of primary producers with a smaller trophic level perched on top.
Inverted-many aquatic ecosystems, the pyramid of biomass may assume an inverted form.
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Pyramid of Energy
An energy pyramid represents the amount of energy at each trophic level and loss of energy at each transfer to another trophic level. Hence the pyramid is always upward, with a large energy base at the bottom.
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Are saprophytes part of energy pyramids
saprophytes (plant, fungus, or microorganism that lives on decaying matter) are not given any place in ecological pyramids even though they play a vital role in the ecosystem
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Bioaccumulation
is the gradual accumulation of pollutants, chemicals or other substances in an organism. It occurs when the rate of loss of the substance from the body of the organism through catabolism (breakdown of complex molecules in living organisms) or excretion is lower than the rate of accumulation of the substance. As persistent organic pollutants like DDT are long-lasting, the risk of bioaccumulation is high even if the environmental levels of the pollutant are not high.
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Biomagnification
refers to progressive bioaccumulation (increase in concentration) at each trophic level with the passage of time. For biomagnification to occur, the pollutant must have a long biological half- life (long-lived) and must not be soluble in water but be soluble in fats. E.g., DDT. If the pollutant is soluble in water, it will be excreted by the organism. Pollutants that dissolve in fats are retained for a long time. Hence it is traditional to measure the amount of pollutants in fatty tissues of organisms such as fish. In mammals, milk produced by females is tested for pollutants since the milk has a lot of fat.
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