Ecological Niches

விளையாடிக் கற்றுக்கொள்ளுங்கள்

ஆற்றல் சம்பாதிக்க இந்த கேள்விகளுக்குப் பதிலளியுங்கள், பின்னர் மீன் பிடித்து ஆராயுங்கள். கணக்கு தேவையில்லை.

கல்வியாளர்களுக்கு: Ecological Niches (Biology, HL)-க்கான தயாரான பாட ஸ்லைடுகள், திருப்புதல் குறிப்புகள் — உங்கள் பாடத்தில் அவற்றைப் பயன்படுத்தவும், அல்லது கற்பவர்கள் நேரலை விளையாட்டாக விளையாடும் ஊடாடும் வகுப்பு செயல்பாடாக தலைப்பை இயக்கவும்.

பாட குறிப்புகள்

Ecological Niches

A habitat is the place where a species lives; a niche is the role of a species within its habitat.
The role of a species includes what it eats, which other species depend on it for food, what time of day it is active, and exactly where in a habitat it lives and feeds.
The niche also includes the abiotic factors (e.g. oxygen, temperature) and biotic factors (e.g. competitors, predators) acting on a species.
No two species can fill the same niche within a habitat; if this happens, they will be in direct competition, and one species will out-compete the other, causing it to die out in that habitat.
Even when species appear to occupy the same niche, there are subtle differences in their role, such as feeding at different times of day or having different food sources.
Feeding location is an example of a feature that may differ between niches.

Interactions in an ecosystem

Anaerobes & Aerobes

All living organisms carry out some form of respiration; aerobic respiration requires oxygen, while anaerobic respiration does not.
Obligate anaerobes are single-celled organisms that can only carry out anaerobic respiration and cannot tolerate oxygen; they are found in oxygen-free environments such as lower soil layers, deep water, and inside other organisms.
Facultative anaerobes mainly respire aerobically but can switch fully to anaerobic respiration in the absence of oxygen, with no negative effects; examples include brewer's yeast (×Saccharomyces cerevisiae×) and×Escherichia coli×.
Obligate aerobes cannot survive without oxygen and rely on aerobic respiration; they may carry out anaerobic respiration for only a few seconds. Examples include most animals, most fungi (not yeast), and some bacteria such as×Mycobacterium tuberculosis×.

Methods of Nutrition

Organisms need energy in the form of ATP, which comes from organic molecules such as carbohydrates transferred during respiration.
The way an organism gains organic molecules to fuel respiration is its method of nutrition; the two main modes are autotrophy and heterotrophy.
An autotroph synthesises its own organic molecules from simple inorganic substances; photoautotrophs use light energy, while chemoautotrophs use energy from oxidation of chemicals.
A heterotroph gains organic molecules from the tissues of other organisms.
Photosynthesis is carried out by autotrophs that use light energy to convert carbon dioxide into organic molecules; photosynthetic pigments such as chlorophyll absorb light energy.
Photosynthetic organisms are producers because they make their own organic molecules without relying on other organisms; they include plants, algae, and photosynthetic bacteria such as cyanobacteria.
Photosynthesis transfers light energy into a chemical form usable by living organisms and releases oxygen into the atmosphere, enabling aerobic respiration.

Holozoic Nutrition, Mixotrophs & Saprotrophs

Holozoic nutrition is used by heterotrophs that gain organic molecules by ingesting, digesting, absorbing, and assimilating molecules from the tissues of other organisms.
Ingestion = eating; digesting = breaking down larger molecules into smaller ones; absorbing = transport of molecules from the digestive tract into cells; assimilation = using molecules to build cells and tissues.
Holozoic nutrition involves internal digestion; animals such as house flies that secrete enzymes onto food externally are heterotrophs but do not use holozoic nutrition.
Mixotrophs use more than one method of nutrition, such as both auto- and heterotrophy; obligate mixotrophs must constantly have access to both methods, while facultative mixotrophs can survive using one method supplemented by the other.
×Euglena×is a mixotroph that can photosynthesise and also take in bacterial cells by endocytosis, digesting them with lysosomal enzymes; it has a light-sensitive spot to position itself for maximum light absorption.
Other examples of mixotrophs include carnivorous plants, corals, and marine plankton such as dinoflagellates.
Saprotrophs are heterotrophs that digest dead organisms and waste material externally by secreting enzymes, then absorb the products; examples include fungi and bacteria, which act as decomposers.
Saprotrophs release mineral ions such as ammonium and phosphate; not all products are absorbed, leaving minerals in the soil for plants. Without saprotrophs, nutrients would remain locked in dead matter.

Fungi as decomposers

Nutrition in Archaea

Archaea are a diverse group of single-celled organisms forming one of the three domains; they vary metabolically, including phototrophic, chemotrophic, and heterotrophic groups.
Phototrophic archaea use light energy to generate ATP; e.g.×Halobacteria×use bacteriorhodopsin to absorb light and pump H⁺ ions across a membrane, producing ATP via ATP synthase.
This is not oxygen-releasing photosynthesis, and×Halobacteria×are not autotrophic; they are photoheterotrophs because they use light for ATP but gain carbon compounds from other organisms.
Chemoautotrophic archaea produce their own carbon compounds using energy from chemicals such as hydrogen gas, ammonia, methane, and hydrogen sulfide.
Chemoheterotrophic archaea use chemicals to produce ATP but gain their carbon compounds from other organisms.
Heterotrophic archaea gain carbon compounds from other organisms and use them to generate ATP, e.g. archaea that break down dead plant material.

Nutrition in Hominidae: Skills

Humans are part of the Hominidae family, along with chimps, gorillas, orangutans, and gibbons; most existing hominids are omnivores.
Chimps are mainly frugivores (fruit-eaters) but also eat other plant matter and some small mammals; gorillas are mainly herbivores, feeding on leafy vegetation and sometimes insects.
Jaw and dentition are specialised for diet: chimps have small jaw muscles and long canines for biting and tearing, while gorillas have strong jaw muscles and large molars and premolars for grinding tough vegetation.
Incisors are chisel-shaped for cutting and biting; canines are pointed for holding and tearing; premolars and molars are flat and ridged for grinding.
The relationship between diet and dentition in existing hominids can be applied to extinct species by studying preserved skulls and jaws.
Dentition is not always a perfect indicator of diet: modern humans eat meat but have plant-eater-like teeth; orangutans and gorillas have pointed canines but do not eat meat; male chimps have longer canines than females despite similar diets.
Teeth may also play roles in defence or competition for mates, so other evidence such as tooth abrasion patterns under a microscope should be considered.
Examples of extinct hominids include×Australopithecus africanus×,×Paranthropus robustus×,×Homo floresiensis×, and×Homo neanderthalensis×.

Deductions from Hominid Fossils

×Paranthropus robustus×had a robust skull with attachment points for large jaw muscles, large molars and premolars, and thick tooth enamel, suggesting a diet of tough plant material.
×Homo floresiensis×had large premolars, small canines, a square robust jaw, and tooth abrasion suggesting a fibrous plant-based diet; hunting/cutting tools provide additional evidence of meat eating.
Scientists make observations (e.g. how teeth of existing hominids relate to diet) and develop theories (e.g. that extinct hominid diets can be deduced from dentition).
New evidence must be taken into account; discrepancies between dentition and diet in modern hominids show that deductions about extinct species may be flawed and additional evidence may be needed.

Adaptations of Herbivores & Plants

Herbivores are heterotrophs that feed on plants; adaptations are characteristics that aid survival in their environment.
Aphids have specialised mouthparts called stylets to pierce plant tissues and reach sugary sap in the phloem; caterpillars, grasshoppers, and beetles have mandibles to cut through leaves.
Grazing mammals such as sheep and horses have flat teeth for grinding plant matter.
Ruminants such as cattle and deer have multi-compartment stomachs, can regurgitate and re-chew food, and have specialised bacteria that produce cellulase to break down cellulose.
Some mammals neutralise plant toxins: deer produce salivary proteins that bind tannins; proboscis monkeys have gut bacteria that neutralise leaf toxins; 'cautious sampling' avoids consuming large amounts of toxic chemicals.
Plants cannot move away from herbivores, so they use mechanical deterrents such as cacti spines, nettle hairs, thick bark, and tiny leaf hairs.
Plants also produce toxic secondary compounds: foxgloves produce digitalis (affects heartbeat), deadly nightshade produces atropine (blocks neurotransmitters), tannins deter by bitter taste, and alkaloids such as caffeine and nicotine deter insects.

Adaptations of Predators & Prey

Predators hunt and eat other animals or consume recently dead animals; prey are hunted and consumed. Adaptations can be chemical, physical, or behavioural.
Predator chemical adaptations include venoms: haemotoxic venoms (e.g. adders, rattlesnakes) damage the circulatory system, while neurotoxic venoms (e.g. mambas, cobras, scorpions, spiders) interfere with nerve impulses.
Predators may use chemical mimicry (e.g. bolas spiders release moth pheromones) or chemical crypsis (scent camouflage, e.g. pirate perch fish) to attract or ambush prey.
Predator physical adaptations include forward-facing eyes for distance perception, excellent vision in birds of prey, Jacobson's organ in snakes, and echolocation in bats.
Predators have body structures for catching prey: cheetahs' long limbs and flexible spines, swordfish streamlined bodies, mantis shrimp modified front limbs, and large canine teeth in carnivorous mammals.
Predator behavioural adaptations include ambush (puff adders, mantis shrimps, crocodiles), pack hunting (orcas, wolves, lions), and pursuit hunting (cheetahs, wolves, painted dogs).
Prey chemical adaptations include toxins (poison dart frogs, skunks, tiger moths) and scent camouflage (puff adders, harlequin filefish).
Prey physical adaptations include eyes on the sides of the skull for wide vision, camouflage, mimicry (owl butterflies, king snakes), aposematism (bright warning colours), and mechanical defences (exoskeletons, shells, spines).
Prey behavioural adaptations include preference for dark sheltered places, fleeing, avoiding predator locations/times, grouping in large groups, mobbing predators, warning calls, and bluffing (playing dead, frill-necked lizards).

Camouflage as an adaptation

Plant Adaptations for Harvesting Light

Plants have whole-organism form adaptations that maximise light absorption for photosynthesis.
Trees form the canopy; emergent trees grow above the canopy, and understory trees grow beneath it. Maximising height allows the tallest trees to gain the most sunlight.
Lianas are woody vines that use tree trunks for support to reach the canopy; they germinate on the forest floor, grow toward tree trunks, and compete with trees for light, nutrients, and moisture.
Epiphytes grow high in tree branches to absorb sunlight without beginning life on the forest floor; they gain nutrients from the canopy (e.g. moss from rainwater, bromeliads collect rainwater, orchids have aerial roots).
Strangler epiphytes begin life in the canopy and grow roots down to the soil, gaining nutrients and water while taking advantage of height; strangler figs can kill their host trees by taking all resources.
Shade-tolerant shrubs and herbaceous plants grow on the forest floor, may contain different photosynthetic pigments, often have large leaves, and produce brightly coloured or strongly scented flowers to attract pollinators in low light.
Shrubs have woody stems but are not tall like trees; herbaceous plants lack woody stems and rely on soft tissues with turgid cells for support.

Fundamental & Realised Niches

The fundamental niche is the full range of conditions and resources in which a species could survive and reproduce, based on its adaptations and tolerance limits.
The realised niche is the actual conditions and resources in which a species exists, due to biotic interactions.
The fundamental niche is the potential distribution of a species, with no competition or predation, and is large in size.
The realised niche is the actual distribution, with competition and predation occurring, and is smaller in size.
Example: the barnacle×Chthamalus dalli×has a wide fundamental niche but its realised niche is restricted to higher up the shore where it avoids competition with×Balanus glandula×.

Competitive Exclusion

A niche can only be occupied by one species; if two species try to occupy the same niche, they compete for the same resources.
The result of competition is that one species out-competes the other until the second species is either forced into a new, slightly different niche or made locally extinct.
Both species may also be forced into a smaller part of their fundamental niches.
The elimination of a competing species from its niche is known as competitive exclusion.
A classic example is×Paramecium aurelia×and×Paramecium caudatum×: grown separately both thrive, but grown together×P. aurelia×out-competes×P. caudatum×, leading to its elimination.
This example occurs under laboratory conditions; in nature it is rare for two species to occupy exactly the same niche.

Interspecific competition

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இலவச முன்னோட்டம் — 61-இல் 8 கேள்விகள். அனைத்தையும் பார்க்க பதிவு செய்யவும்.

1.Which of the following correctly describe aspects of an ecological niche? I. How a species gains its food II. Abiotic factors that influence species growth III. Biotic factors that influence species survival
Easy
- AI only
- BI and II only
- CII and III only
- DI, II and III
2.Saccharomyces cerevisiae is a species of yeast that can survive at a range of oxygen concentrations, including in the absence of oxygen. Which term describes Saccharomyces cerevisiae?
Easy
- AObligate anaerobe
- BFacultative anaerobe
- CObligate aerobe
- DMixotroph
3.Which of the following statements about ecological niches is correct?
Medium
- ACompetition reduces the size of an ecological niche.
- BAn ecological niche can be shared between two similar species.
- CCompetition for a niche always results in local extinction for one species.
- DA realised niche is larger than a fundamental niche.
4.A habitat is the role of a species within its environment, while a niche is the place where a species lives.
Easy
True or false?
5.Which of the following are adaptations that aid herbivory? (select all that apply)
Medium
- AThe presence of an enzyme that breaks down cellulose.
- BProduction of toxic secondary compounds.
- CProteins that bind to toxins.
- DSharp spines to deter herbivores.
6.The Ghost Orchid (Epipogium aphyllum) is a rare plant species which lacks leaves or chlorophyll. The plant has formed a symbiotic relationship with a fungus in order to obtain the nutrition it requires. The growth of the fungus is slowed as a result of the relationship. Which of the following rows correctly describes E. aphyllum?
Medium
- AHeterotroph: ✓, Autotroph: X, Parasite: X, Saprotroph: ✓
- BHeterotroph: X, Autotroph: ✓, Parasite: X, Saprotroph: ✓
- CHeterotroph: ✓, Autotroph: X, Parasite: ✓, Saprotroph: ✓
- DHeterotroph: ✓, Autotroph: X, Parasite: ✓, Saprotroph: X
7.Match each term with its correct description.
Medium
- Obligate anaerobe
- Facultative anaerobe
- Obligate aerobe
- Cannot survive in the absence of oxygen
- Can only carry out anaerobic respiration and cannot tolerate oxygen
- Mainly respires aerobically but can switch fully to anaerobic respiration
8.Place the steps of holozoic nutrition in the correct order.
Medium
- Assimilation
- Ingestion
- Absorption
- Digestion

மேலும் கேள்விகள்

9.Which of the following are features that can be considered part of an ecological niche? (select all that apply)
Medium
- AThe time of day at which a species is active
- BThe exact location within a habitat where a species feeds
- CThe physical place where a species lives, such as a rocky shore
- DThe abiotic factors acting on a species
- EThe biotic factors acting on a species
10.Match each nutritional term with its correct description.
Medium
- Holozoic nutrition
- Saprotrophic nutrition
- Mixotrophic nutrition
- Ingesting, digesting, absorbing and assimilating molecules from the tissues of other organisms, with internal digestion
- Secreting enzymes onto dead organisms or waste material and digesting it externally before absorbing the products
- Using more than one method of nutrition, such as both autotrophy and heterotrophy
11.Place the stages of holozoic nutrition in the correct order, starting with the first stage.
Medium
- Ingestion
- Digestion
- Absorption
- Assimilation
12.Which of the following best describes an obligate anaerobe?
Medium
- AAn organism that can only carry out anaerobic respiration and cannot tolerate oxygen
- BAn organism that mainly respires aerobically but can switch to anaerobic respiration in the absence of oxygen
- CAn organism that cannot survive without oxygen and relies on aerobic respiration
- DAn organism that uses both autotrophic and heterotrophic nutrition
13.Which of the following statements about archaea are correct? (select all that apply)
Medium
- APhototrophic archaea use light energy to generate ATP but are not considered autotrophic.
- BChemoautotrophic archaea produce their own carbon compounds using energy released from chemicals.
- CHeterotrophic archaea gain their carbon compounds from other organisms.
- DAll archaea are obligate anaerobes.
- EHalobacteria use bacteriorhodopsin to absorb light energy and pump H+ ions across a membrane.
14.Which of the following statements about fundamental and realised niches is correct?
Medium
- AA realised niche is the actual conditions and resources a species uses in the presence of competitors, and is smaller than its fundamental niche.
- BA fundamental niche is smaller than a realised niche because it is limited by competition.
- CA realised niche is the full range of conditions a species could use if there were no limiting factors.
- DFundamental and realised niches are always the same size.
15.When two species compete for the same niche, one species may be forced to occupy a new, slightly different niche or become locally extinct.
Easy
True or false?
16.In the classic experiment with Paramecium aurelia and Paramecium caudatum, what is the expected outcome when both species are grown together in the same habitat?
Medium
- AP. aurelia outcompetes P. caudatum, leading to the elimination of P. caudatum.
- BBoth species coexist indefinitely because they occupy different niches.
- CP. caudatum outcompetes P. aurelia, leading to the elimination of P. aurelia.
- DBoth species die out because they compete for the same resources.
17.Which of the following are adaptations that aid herbivory in mammals? (select all that apply)
Medium
- AFlat teeth for grinding plant matter
- BStomachs with several compartments allowing regurgitation and re-chewing
- CSpecialised bacteria in the digestive tract that break down cellulose
- DProducing proteins in saliva that bind to tannins
- ESharp canine teeth for tearing meat
18.Match each type of adaptation to the correct example.
Medium
- Chemical adaptation of a predator
- Physical adaptation of a predator
- Behavioural adaptation of a predator
- Venom produced by adders that damages the circulatory system
- Excellent vision in birds of prey for detecting small prey
- Lions cooperating in a pack to hunt
19.Spirulina is grown in a glucose medium and exposed to different light intensities, and its growth is compared with an autotrophic alga. Which result would best support the conclusion that Spirulina is a mixotroph?
Hard
- ASpirulina grows in the dark as well as in the light, while the autotrophic alga only grows in the light.
- BSpirulina and the autotrophic alga both grow only when light is present.
- CSpirulina grows only in the dark, while the autotrophic alga grows only in the light.
- DSpirulina grows faster than the autotrophic alga at all light intensities.
20.Place the following events in the correct order to show how a saprotroph obtains nutrients.
Medium
- Secrete digestive enzymes onto dead organic matter
- Hydrolyse large biological molecules into smaller products
- Absorb the products of external digestion
- Release mineral ions such as ammonium and phosphate into the soil
21.Which of the following are adaptations of prey animals to avoid predation? (select all that apply)
Medium
- AEyes positioned on the sides of the skull giving a wide field of vision
- BBright warning colouration (aposematism)
- CProducing toxins in the skin
- DHaving large canine teeth for tearing prey
- EMimicking the appearance of a predator, such as owl butterflies
22.Detritivores such as earthworms use the same method of nutrition as saprotrophic fungi.
Easy
True or false?
23.Which of the following is an example of a mechanical deterrent against herbivory in plants?
Medium
- ASharp spines on cacti
- BProduction of digitalis by foxgloves
- CProduction of tannins that taste bitter
- DProduction of caffeine that is toxic to insects
24.A student observes a bacterial species that grows well in the presence of oxygen but can also survive and grow when oxygen is completely removed, with no harmful effects. Which term best describes this organism?
Medium
- AObligate aerobe
- BObligate anaerobe
- CFacultative anaerobe
- DPhotoautotroph
25.Modified atmosphere packaging (MAP) for red meat uses about 80% O₂ and 20% CO₂, while MAP for chicken uses about 20% O₂ and 80% CO₂. Which conclusion is best supported by this information?
Medium
- AThe gas mixture must be designed to match the oxygen requirements of the microorganisms that spoil each meat type.
- BRed meat spoils only in the absence of oxygen, so it needs more O₂ than chicken.
- CChicken is preserved by oxygen, so it needs a higher O₂ concentration than red meat.
- DThe same gas mixture can be used for all meats because the spoilage bacteria are identical.
26.Which of the following are features that can be part of a species' ecological niche? (select all that apply)
Medium
- AThe time of day the species is active
- BThe abiotic factors acting on the species
- CThe exact place in the habitat where the species feeds
- DThe species' scientific name
- EThe species' DNA base sequence
27.An obligate anaerobe can survive in an oxygen-rich environment because it can switch to aerobic respiration.
Easy
True or false?
28.Match each adaptation to the correct category of predator or prey adaptation.
Medium
- Haemotoxic venom in adders
- Eyes positioned on the sides of the skull in prey
- Ambush predators remaining motionless for long periods
- Bright warning colours in poison dart frogs
- Chemical adaptation of a predator
- Physical adaptation of prey
- Behavioural adaptation of a predator
- Aposematism in prey
29.Place the following events in the correct order to show how a saprotroph such as a fungus obtains nutrients from dead material.
Medium
- Secrete digestive enzymes onto the dead material
- Enzymes hydrolyse biological molecules externally
- Absorb the products of digestion
- Release mineral ions such as ammonium and phosphate into the soil
30.A student grows three bacterial species at different partial pressures of oxygen and records growth. Species X grows only at 0% oxygen and dies at higher concentrations. Species Y grows best at 20% oxygen but also grows, without harm, at 0%. Species Z grows only at 20% oxygen and dies at 0%. Which row correctly identifies the metabolic strategies of X, Y and Z?
Medium
- AX = obligate anaerobe; Y = facultative anaerobe; Z = obligate aerobe
- BX = facultative anaerobe; Y = obligate anaerobe; Z = obligate aerobe
- CX = obligate anaerobe; Y = obligate aerobe; Z = facultative anaerobe
- DX = obligate aerobe; Y = facultative anaerobe; Z = obligate anaerobe
31.A modified atmosphere package for red meat contains 80% O₂ and 20% CO₂. A 250 g gas mixture is used. What mass of oxygen, in grams, is present in the package?
Hard
- A200 g
- B80 g
- C20 g
- D50 g
32.Spirulina was grown in a glucose medium at increasing light intensities and its growth rate was compared with an autotrophic alga grown under the same conditions. Which result would best support the conclusion that Spirulina is a mixotroph?
Medium
- ASpirulina grows in the dark in the glucose medium, but its growth rate increases as light intensity increases.
- BSpirulina grows only when light is present, and its growth rate is identical to the autotrophic alga.
- CSpirulina grows only in the dark and stops growing when light is supplied.
- DSpirulina grows at the same rate as the autotrophic alga at all light intensities.
33.Which of the following statements about the realised niche of Chthamalus dalli is correct?
Medium
- AIt is smaller than its fundamental niche because of competition with Balanus glandula.
- BIt is larger than its fundamental niche because Chthamalus can tolerate more conditions.
- CIt is the same as its fundamental niche because no other barnacle species are present.
- DIt is restricted to the lower shore where Balanus glandula is most abundant.
34.Which of the following are valid experimental controls or precautions when investigating the growth of bacteria at different oxygen concentrations? (select all that apply)
Medium
- AUse the same growth medium and temperature for all oxygen concentrations.
- BMeasure the amount of bacterial growth using a consistent method, such as optical density or colony count.
- CUse a different bacterial species for each oxygen concentration.
- DInclude a sealed control with no bacteria to check for contamination.
- EChange the temperature for each oxygen concentration to speed up growth.
35.Saprotrophs digest their food externally by secreting enzymes onto dead material, while detritivores such as earthworms digest their food internally using holozoic nutrition.
Medium
True or false?
36.Match each experimental observation with the correct conclusion about an organism's method of nutrition.
Medium
- Organism grows in the dark in a glucose medium and also grows faster in light.
- Organism grows only when oxygen is absent and dies when oxygen is present.
- Organism secretes enzymes onto dead material and absorbs the products.
- Organism cannot survive without oxygen.
- Mixotroph
- Obligate anaerobe
- Saprotroph
- Obligate aerobe
37.Place the following steps in the correct order to show how a saprotroph such as a fungus obtains nutrients from dead material.
Medium
- Secrete digestive enzymes onto the dead material
- Hydrolyse biological molecules into smaller products
- Absorb the products of digestion
- Release mineral ions into the surrounding soil
38.What is the term for the place where a species lives?
Easy
- AIts habitat
- BIts niche
- CIts ecosystem
- DIts population
39.An ecological niche includes the abiotic factors acting on a species.
Easy
True or false?
40.Which term describes an organism that synthesises its own organic molecules from simple inorganic substances?
Easy
- AAutotroph
- BHeterotroph
- CSaprotroph
- DDetritivore
41.What is the term for an organism that synthesises its own organic molecules from simple inorganic substances in its environment?
Easy
42.Complete the sentence about ecological niches.
Medium
The role of a species within its habitat is known as its ____, while the place where a species lives is its ____.
43.The MAP used to preserve red meat contains around 80% oxygen. If a 500 g pack of beef is stored in this atmosphere, what mass of oxygen, in grams, is present?
Medium
44.Complete the sentence about Chthamalus dalli and Balanus glandula.
Medium
The fundamental niche of Chthamalus dalli is ____ than its realised niche, because competition with Balanus glandula restricts it to a smaller area.
45.A modified atmosphere package for red meat contains 80% oxygen. If the package contains 500 g of gas mixture, what mass of oxygen, in grams, is present?
Medium
46.Complete the sentence about epiphytes.
Medium
Epiphytes grow high up in tree branches to absorb more ____, but they do not begin their lives on the forest floor.
47.Complete the sentence about the Ghost Orchid (Epipogium aphyllum). It lacks leaves and chlorophyll and obtains nutrition from a fungus, while the fungus's growth is slowed. Therefore, E. aphyllum is a ___ and a ___.
Easy
E. aphyllum is a ____ and a ____.
48.A modified atmosphere package for red meat contains 500 g of gas mixture, of which 80% is oxygen. Calculate the mass of oxygen, in grams, present in the package.
Medium
49.A modified atmosphere package for chicken contains 750 g of gas mixture, of which 20% is oxygen and 80% is carbon dioxide. Calculate the mass of carbon dioxide, in grams, present in the package.
Medium
50.Name the term for an organism that can use both autotrophic and heterotrophic methods of nutrition.
Medium
51.Complete the sentence about the Ghost Orchid (Epipogium aphyllum).
Medium
The Ghost Orchid lacks leaves and chlorophyll and obtains nutrition from a ____, while the fungus's growth is ____ as a result of the relationship.
52.A modified atmosphere package for chicken contains 750 g of gas mixture, of which 80% is carbon dioxide. Calculate the mass of carbon dioxide, in grams, present in the package.
Medium
53.Distinguish between a fundamental and a realised niche.
Hard
54.Explain how the results of an investigation into Spirulina growth in a glucose medium at different light intensities can show that Spirulina is a mixotrophic organism.
Hard
55.Explain a range of adaptations that aid animals in holozoic nutrition.
Hard
56.Outline the metabolic diversity present in the archaea.
Hard
57.The MAP used to preserve red meat contains around 80% oxygen. If a 500 g pack of beef is stored in this atmosphere, what mass of oxygen, in grams, is present?
Medium
- A360 g
- B440 g
- C400 g
- D480 g
58.A modified atmosphere package for red meat contains 80% oxygen. If the package contains 500 g of gas mixture, what mass of oxygen, in grams, is present?
Medium
- A360 g
- B440 g
- C400 g
- D480 g
59.A modified atmosphere package for red meat contains 500 g of gas mixture, of which 80% is oxygen. Calculate the mass of oxygen, in grams, present in the package.
Medium
- A440 g
- B400 g
- C360 g
- D480 g
60.A modified atmosphere package for chicken contains 750 g of gas mixture, of which 20% is oxygen and 80% is carbon dioxide. Calculate the mass of carbon dioxide, in grams, present in the package.
Medium
- A720 g
- B660 g
- C600 g
- D540 g
61.A modified atmosphere package for chicken contains 750 g of gas mixture, of which 80% is carbon dioxide. Calculate the mass of carbon dioxide, in grams, present in the package.
Medium
- A660 g
- B720 g
- C540 g
- D600 g

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