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WorksheetsPage 1
Total questions: 150
Worksheet time: 1hrs 15mins
Variations caused due to mutations are best described as
random and directionless
random and directional
random and small
random, small and directional
Which statement about homology and evolution is not true?
Homologous organs share structure but differ function
Homology indicates common ancestry
Homologous structures arise from convergent evolution
Flippers of whales and dolphins are homologous
A population is in Hardy–Weinberg equilibrium with alleles A (dominant) and a (recessive). If allele frequency of A is 0.6, the expected genotype frequency of Aa is
0.21
0.42
0.32
0.48
Early Greek philosophers proposed that life came to Earth from another planet in the form of
Gemmules
Gametes
Seeds
Spores
Post‑industrialisation in England affected moth populations. The expected effect of natural selection on white‑winged versus dark‑winged moths was
Both less in number
Less white than dark
Both more in number
More white than dark
The graph shows number of giraffes versus neck length forming a peaked curve. Which option best describes the selection process affecting giraffe neck length?
Directional selection favoring longer necks
Stabilising selection with longer necks selected further
Disruptive selection favoring smaller and longer necks
Stabilising selection favoring medium neck lengths
Thorn of Bougainvillea and tendril of Cucurbita are examples of
homologous organs
vestigial organs
retrogressive evolution
analogous organs
Darwin’s finches are an excellent example of
seasonal migration
adaptive radiation
connecting links
brood parasitism
If allele a has frequency 0.4 in an equilibrium population, what is the expected frequency of genotype aa?
0.36
0.24
0.48
0.16
Which observation most strongly supports common ancestry of whales and dolphins?
Analogous fin function in swimming
Similar habitats and diet
Homologous flipper bone arrangement
Convergent streamlined body shape
Evolution of different species in a given area starting from a point and spreading to other geographical areas is known as
migration
adaptive radiation
natural selection
divergent evolution
The theory of spontaneous generation stated that
life arose from living forms only.
life can arise from both living and non-living.
life can arise from non-living things only.
life arises spontaneously, neither from living nor from non-living.
Palaentological evidences for evolution refer to the
development of embryo
analogous organs
fossils
homologous organs
The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because
they have biochemical similarities
one organism has given rise to another
they share a common ancestor
they perform the same function
Which of the following organs are homologous?
Forelimbs of man and wings of bat
Wings of Bat and bird
Wings of Bat and Pterodactyl
None of these
Homologous organs show
parallel evolution
divergent evolution
natural selection
convergent evolution
Analogous organs arise due to
convergent evolution
divergent evolution
genetic drift
artificial selection
Evolution of life shows that life forms had a trend of moving from
land to water
dryland to wet land
fresh water to sea water
water to land
Viviparity is considered to be more evolved because
the young ones are left on their own.
the young ones are protected by a thick shell.
the embryo takes a long time to develop.
the young ones are protected inside the mother's body and are looked after they are born leading to more chances of survival.
Fossils are generally found in
igneous rocks
any type of rock
metamorphic rocks
sedimentary rocks
According to Hugo de Vries, speciation is due to
inter specific breeding
intraspecific breeding
accumulation of small variations
saltation
Which type of selection explains industrial melanism observed in moth, Biston betularia?
Artificial
Disruptive
Directional
Stabilising
The most accepted line of descent in human evolution is
Australopithecus → Ramapithecus → Homo erectus → Homo habilis → Homo sapiens.
Ramapithecus → Homo habilis → Homo erectus → Homo sapiens
Australopithecus → Ramapithecus → Homo sapiens → Homo habilis
Homo erectus → Homo habilis → Homo sapiens
Which of the following is an example for link species?
Sea weed
Lobe fish
Chimpanzee
Dodo bird
Match the scientists in Column I with the ideas in Column II: A. Darwin, B. Oparin, C. Lamarck, D. Wagner; (i) Abiogenesis, (ii) Use and disuse of organs, (iii) Continental drift theory, (iv) Evolution by natural selection. Choose the correct pairing.
A-(i); B-(iv); C-(ii); D-(iii)
A-(ii); B-(i); C-(iii); D-(iv)
A-(iv); B-(iii); C-(ii); D-(i)
A-(iv); B-(i); C-(ii); D-(iii)
Stabilising selection favors which outcome in a population?
none of these
intermediate form
both extreme forms
only one extreme form
Disruptive selection favors which outcome in a population?
only one extreme form
both extreme forms
intermediate form
none of these
The phenomenon of "Industrial melanism" demonstrates which evolutionary process?
induced mutation
genetic drift
natural selection
geographical isolation
In 1953, S. L. Miller simulated primitive Earth conditions to show abiotic synthesis of organic molecules. Which set best describes those conditions?
low temperature, volcanic storms, reducing atmosphere
high temperature, volcanic storms, reducing atmosphere with CH4, NH3
low temperature, volcanic storms, oxygen-rich atmosphere
high temperature, volcanic storms, non-reducing atmosphere
Which is the correct Hardy–Weinberg equation for a two-allele locus?
p2 + pq + q2 = 0
p2 + pq + q2 = 1
p2 + pq + q2 = infinity
p2 + 2pq + q2 = 1
Assertion–Reason: Assertion: Louis Pasteur’s experiments showed that new organisms appeared in an open flask with heat-killed yeast. Reason: Life arises from pre-existing life. Choose the correct option.
Assertion wrong; reason correct
Assertion correct; reason wrong
Assertion and reason both correct; reason does not explain assertion
Assertion and reason both correct; reason explains assertion
Which scientist is most directly associated with "use and disuse" theory?
Wagner
Darwin
Lamarck
Oparin
Continental drift theory is linked with which scientist among the list?
Wagner
Lamarck
Oparin
Darwin
Industrial melanism led to increased dark morphs of moths during heavy pollution. Which mechanism best explains the shift?
directional selection favoring dark morphs
disruptive selection splitting color forms
random genetic drift in small populations
stabilising selection around mean color
Which statement best describes analogous organs, as illustrated by wings of butterflies and birds?
Anatomically similar with identical structure
Functionally different but anatomically identical
Anatomically different yet functionally similar
Both anatomically and functionally identical
Disruptive selection typically causes which population outcome?
Elimination of extreme phenotypes
Split into two or more groups
Shift toward intermediate traits
One uniform average phenotype
In early evolution, which molecule is considered the hereditary material of the earliest cells?
Protein-based enzymes
Polysaccharide templates
DNA as primary genome
RNA as hereditary molecule
Which principle explains occurrence of variations in population and species by focusing on genetic equilibrium?
Founder principle
Hardy–Weinberg principle
Bergmann’s rule
Adaptive radiation model
The founder effect may lead most directly to which outcome?
Formation of new species
Restoration of gene flow
Increase in population size
Elimination of mutations
Excessive use of herbicides and pesticides most likely selects for which microbial trait?
Broader host specificity
Higher mutation frequency
Reduced reproductive rate
Chemical resistant varieties
Darwin’s finches show different beak types mainly due to which evolutionary process?
Artificial selection
Genetic assimilation
Adaptive radiation
Convergent evolution
Genetic drift primarily refers to which population-level change?
Changes in allele frequency
Increase in mutation rate
Directional selection pressure
Gene flow between populations
Among primates, which species is identified as the closest relative of present-day humans?
Gorilla
Chimpanzee
Gibbon
Orangutan
The industrial melanism observed in British moths after industrialisation showed which trend in white-winged moth numbers?
Increased substantially
Stayed approximately constant
Varied seasonally only
Decreased drastically
In a simulation of the Urey–Miller experiment, which gas mixture is heated and exposed to electrical sparks to test origin-of-life chemistry?
CO2, N2, H2O, H2S
H2O, CH4, H2, NH3
O2, CO, NO2, SO2
H2O, CH3OH, O2, Ar
Which error prevented the desired results in an early origin-of-life experiment?
Excluding methane from mixture
Maintaining pressure too high
Using O2 instead of H2 gas
Using glass instead of metal
In Urey–Miller’s conclusion, what was shown about life’s origin?
Evolution only by natural selection
Abiogenesis from inorganic molecules
Direct panspermia of spores
Immediate formation of cells
What was a temperature issue that led to failure in a replication attempt of the origin-of-life setup?
Cooled rapidly with ice water
Varied randomly from 20–50°C
Held constant at 37°C
Maintained 80°C not 800°C
What was the main purpose of Urey–Miller’s experiment?
Model fossilization in sediments
Confirm abiogenesis from organic matter
Measure ozone formation in storms
Test photosynthesis in algae
Which statement contrasts abiogenesis with panspermia?
Life started by plants vs animals
Life began in oceans vs deserts
Life came from viruses vs bacteria
Life formed on Earth vs spores from space
According to Darwin, what role does an individual play in natural selection?
Eliminates all mutations
Controls environmental changes
Creates new species instantly
Passes variations and adaptations
What term describes the evolution of different species from a common ancestor across habitats in an area?
Directional selection
Genetic drift
Convergent evolution
Adaptive radiation
How do the Galápagos finches demonstrate adaptive radiation?
Migrated without change
Diverged in size, color, beaks
Cloned identical offspring
Hybridized into one form
What is meant by the fitness of an individual in Darwinian terms?
Speed compared to competitors
Capacity to grow larger muscles
Skill to find abundant food
Ability to survive and pass genes
Which evolutionary process best explains similarities between the wolf and Tasmanian wolf?
Artificial selection by humans
Co-evolution with same prey
Parallel mutation in genes
Convergent evolution of niches
Which animal likely evolved along with the Tasmanian wolf due to similar ecological roles?
Giant herbivorous wombat
Komodo dragon predator
Placental wolf as analogue
Marine dolphin hunter
Name the process resulting in resemblance between the wolf and Tasmanian wolf despite different lineages.
Stabilizing selection
Allopatric speciation
Artificial breeding
Convergent evolution
Which geographical region is depicted as the habitat for the organisms shown in the diagram?
South America rainforest
Eurasia temperate zones
Australia and nearby islands
Africa continent overall
Adaptive radiation is best described as which evolutionary process?
Development of identical genes across species
Evolution of diverse forms from a common ancestor
Random drift without environmental influence
Hybridization leading to sterile offspring
Which pair illustrates convergent evolution resulting in similar niches despite different lineages?
Mouse and marsupial mouse
Wolf and Tasmanian wolf
All of the listed pairs
Flying squirrel and flying phalanger
What key difference distinguishes a wolf from a Tasmanian wolf?
Both are marsupial mammals
Tasmanian wolf is a placental mammal
Wolf is a placental mammal
Neither gives live birth
Which example from the diagram supports adaptive radiation within marsupials?
Marsupial mole, marsupial mouse, numbat
Tasmanian tiger cat, wolf, mouse
Bobcat, lemur, flying squirrel
Mole, anteater, spotted cuscus
Convergent evolution leads to organisms that are best described as
Correlated groups sharing ancestry
Unrelated groups with similar functions
Identical species across continents
Populations separating without selection
Which pair in the diagram exemplifies gliding adaptations in different mammalian groups?
Lemur and bobcat
Mole and marsupial mole
Flying squirrel and flying phalanger
Mouse and marsupial mouse
Why might placental wolf and Tasmanian wolf occupy similar habitats?
Shared recent common ancestor
Convergent evolution to similar niches
Human introduction to the region
Identical reproductive anatomy
Which animal listed is an insectivorous marsupial analogous to an anteater?
Spotted cuscus
Numbat (anteater)
Bobcat
Marsupial mouse
Which statement about lemur and spotted cuscus sharing habitat is most accurate?
They share habitat due to genetic drift
They share habitat due to hybrid speciation
They share habitat due to convergent evolution
They share habitat due to correlated evolution
Animal husbandry and plant breeding programmes are examples of
reverse evolution
natural selection
artificial selection
mutation
DDT resistance in mosquito is an example of
stabilizing selection
directional selection
disruptive selection
no selection
Darwin’s finches are an excellent example of
both (a) and (b)
divergent evolution
adaptive selection
connecting links
Identify the correct type of evolution exhibited by the two animals shown, living in the same habitat in Australia.
convergent evolution
divergent evolution
disruptive selection
homologous ancestry
At which stage during evolution did humans use hides to protect their bodies and bury their dead?
Homo habilis
Neanderthal man
Homo erectus
Java man
Assertion (A): Sediments of different aged rocks contain fossils and different life forms. Reason (R): The age of fossils is estimated by radiocarbon dating.
A is wrong but R is correct
A is correct but R is wrong
Both A and R are correct but R does not explain A
Both A and R are correct and R explains A
Assertion (A): Pasteur’s experiment supported the theory of abiogenesis. Reason (R): Theory of abiogenesis states that first form of life arose from non-living molecules.
A is wrong but R is correct
Both A and R are correct and R explains A
Both A and R are correct but R does not explain A
A is correct but R is wrong
Assertion (A): Darwin’s finches show adaptive radiation. Reason (R): All finches arose from common ancestral seed-eating stock and underwent adaptive changes.
Both A and R are correct but R does not explain A
Both A and R are correct and R explains A
A is wrong but R is correct
A is correct but R is wrong
Observe the picture. Name the naturalist and state the explanation he gave for how evolution of giraffe forms occurred in this example.
Darwin, natural selection acts on neck length
Lamarck, inheritance of acquired longer neck
Mendel, segregation of neck length alleles
Wallace, random drift changing neck length
Which selection pattern most likely maintains intermediate phenotypes and reduces extremes in a stable environment?
balancing mutation
stabilizing selection
directional selection
disruptive selection
Which hypothesis did S.L. Miller aim to test using his experimental apparatus with electrodes, gases, and boiling water?
RNA world self‑replicating ribozymes
Panspermia arrival of life from comets
Endosymbiotic origin of mitochondria and chloroplasts
Primordial soup origin of organic molecules
Meteorite analysis supports which idea about the origin of life molecules?
Exclusive synthesis only in deep‑sea vents
Immediate formation of DNA double helix
Extraterrestrial delivery of organic compounds
Direct emergence of complex cells
In the snake population diagram, brown snakes are dominant (A) and grey snakes recessive (a). If recessive phenotype frequency q2 is 9%, what is the approximate frequency of heterozygotes?
About 54 percent of the population
About 45 percent of the population
About 9 percent of the population
About 30 percent of the population
Using the same snake scenario where q2=0.09 , what is the approximate frequency of homozygous dominant individuals?
About 64 percent of individuals
About 27 percent of individuals
About 36 percent of individuals
About 51 percent of individuals
Which evolutionary mechanism best explains the change from population‑one to population‑two after bird migration in the snake diagram?
Nonrandom mating among grey snakes
Natural selection by predation pressure
Genetic drift due to small sample size
Mutation increasing recessive allele rate
Among skulls labeled A, B, and C, which two are more similar to each other in overall morphology?
A and C show closest similarity
B and C show closest similarity
None of the three are similar
A and B show closest similarity
Name the primate type that existed around 1.5 million years ago and is man‑like in features.
Homo erectus with upright gait
Homo habilis tool‑maker early
Australopithecus robustus form
Neanderthal late European type
According to Hugo de Vries, what primarily causes speciation?
Hybridization between close species
Geographic isolation of populations
Gradual selection over many generations
Sudden mutations producing new forms
Why is Archaeopteryx significant in studies of organic evolution?
It is a transitional fossil showing reptile‑bird traits
It documents origin of flowering plants
It demonstrates modern mammal diversification
It proves convergent evolution in insects
Why are coelacanth lobefins considered highly significant to evolutionary biologists?
They demonstrate recent rapid speciation
They evolved wings from forelimbs
They show direct mammalian ancestry
They represent living fossils with lobed fins
Darwin’s finches are a classic example of which evolutionary pattern?
Adaptive radiation producing diverse niches
Stabilizing selection maintaining mean trait
Parallel evolution in unrelated groups
Directional selection toward larger beaks
Which statement correctly defines fossils and one way they support biological evolution?
Recent bones; show rapid seasonal shifts
Preserved remains; document chronological changes
Living specimens; demonstrate present biodiversity
Mineral crystals; reveal genetic mutations directly
In Miller’s apparatus, what was the function of the condenser connected above the spark chamber?
Trap liquid water containing products
Introduce gases from the vacuum pump
Generate high‑voltage electrical sparks
Cool vapors to form water droplets
Which pair of statements is correct regarding ecological interactions and plant chemicals?
(ii) and (iv)
(i) and (iii)
(iii) and (iv)
(i) and (ii)
Mass of living matter at a trophic level in an area at any time is called
standing crop
detritus
humus
standing state
Identify the possible link “A” in the food chain: Plant → insect → frog → “A” → eagle
wolf
parrot
rabbit
cobra
Which one is not a functional unit of an ecosystem?
Stratification
Productivity
Decomposition
Energy flow
The upright pyramid of number is absent in
lake
pond
both (a) and (b)
grassland
The rate of formation of new organic matter by rabbit in grassland is called
secondary productivity
net productivity
gross primary productivity
net primary productivity
Decomposers like fungi and bacteria are
autotrophs
heterotrophs
saprotrophs
chemo-autotrophs
Mineralisation by microorganisms helps in release of
inorganic nutrients from humus
both organic and inorganic nutrients
organic nutrients from humus
inorganic nutrients from detritus
Productivity is rate of biomass production expressed as
kcal m⁻³ yr⁻¹
g m⁻² yr⁻¹
kcal m⁻² yr⁻¹
g⁻¹ yr⁻¹
An inverted pyramid of biomass can be found in
Grassland
Marine
Forest
Tundra
Pyramid of numbers is
neither upright nor inverted
either upright or inverted
always inverted
always upright
About 10% of energy passing from one trophic level to another is
respired and becomes heat
passed out as faces or urine
stored as body tissue
recycled to autotrophs
If carbon fixed by producers has passed through three species, the last species’ trophic level would be
tertiary producer
tertiary consumer
scavenger
secondary consumer
Humans benefit from ecosystems because ecosystems provide
maintenance of a clean water supply
buffers from natural disasters such as floods
Which ecosystem type is most likely where evaporation exceeds precipitation and mean annual rainfall is below 100 mm?
Shrubby forest with dense canopy
Mangrove with saline wetlands
Desert with arid conditions
Grassland with sparse trees
The zone at a lake or ocean edge that is alternately exposed to air and immersed in water is called:
Benthic zone on the bottom
Pelagic zone in open waters
Littoral zone near the shore
Lentic zone in still waters
Edaphic factor primarily refers to:
Altitude influencing climate
Water availability in habitats
Soil characteristics in ecosystems
Relative humidity of air
Assertion: Some aquatic ecosystems have inverted biomass pyramids. Reason: More energy is required by organisms at higher trophic levels.
Both statements true; reason correctly explains
Both statements true; reason does not explain
Assertion false; reason true
Assertion true; reason false
Assertion: A network of food chains existing together is a food web. Reason: An animal like a kite cannot be part of a food web.
Both statements true; reason correctly explains
Assertion false; reason true
Both statements true; reason does not explain
Assertion true; reason false
Assertion: In a food chain, members of successive trophic levels are fewer. Reason: Organism numbers at any trophic level are independent of food availability at lower levels.
Both statements true; reason correctly explains
Both statements true; reason does not explain
Assertion true; reason false
Assertion false; reason true
Assertion: Vertical distribution of different species at different levels is called stratification. Reason: Trees occupy top strata, shrubs the second, herbs and grasses the bottom layers.
Assertion false; reason true
Both statements true; reason correctly explains
Assertion true; reason false
Both statements true; reason does not explain
Assertion: Pyramid of energy is always upright. Reason: Energy is lost as heat at each step when flowing to the next trophic level.
Both statements true; reason correctly explains
Assertion true; reason false
Both statements true; reason does not explain
Assertion false; reason true
Assertion: Decomposers feed on detritus, derived from all levels. Reason: At each level of energy flow in the food web, energy is lost to respiration.
Both statements true; reason correctly explains
Assertion false; reason true
Both statements true; reason does not explain
Assertion true; reason false
Assertion: In terrestrial ecosystems, detritus food chain is the major conduit for energy flow. Reason: Solar energy is the direct energy source in a detritus food chain.
Both statements true; reason correctly explains
Assertion true; reason false
Assertion false; reason true
Both statements true; reason does not explain
Which term best describes an organism’s specific position in a food chain where it performs a functional role?
Population within its habitat
Guild of interacting consumers
Niche within community dynamics
Trophic level in the food chain
What is the typical direction of energy transfer in a linear food chain?
Cyclic among decomposers only
Unidirectional from producers upward
Bidirectional between all levels
From consumers to producers
Which principle states that only about 10% of energy is transferred to the next trophic level?
Lotka–Volterra energy law
Law of limiting factors
Lindeman’s ten percent law
Gause’s competitive exclusion rule
Why do most food chains contain only about four or five trophic levels?
Predators cap population sizes
Energy loss limits transfer upward
Nutrient cycles stop at consumers
Producers outcompete higher carnivores
In an ecological pyramid of biomass for phytoplankton → zooplankton → small fish → large fish, which shape is most likely?
Flat because biomass is constant
Diamond with peak at zooplankton
Upright with decreasing biomass upward
Inverted due to producer biomass low
Given producer biomass 4 kg/m² and zooplankton biomass 11 kg/m², what does this indicate about aquatic biomass pyramids?
They are always upright in water
They can be inverted at lower levels
They cannot exceed producer biomass
They equalize across all trophic levels
If only 10% of energy passes to the next trophic level, what percent is typically lost due to respiration and other activities?
About ten percent lost
About fifty percent lost
About one percent lost
About ninety percent lost
Which statement best explains stability in ecosystems with interacting biotic and abiotic components?
Stability arises solely from abiotic cycles
Interactions through food chains support stability
Energy input is independent of producers
Predation alone ensures system stability
Choose the correct sequence of trophic levels for the provided aquatic example.
Large fish → small fish → zooplankton → phytoplankton
Phytoplankton → zooplankton → small fish → large fish
Zooplankton → phytoplankton → small fish → large fish
Phytoplankton → small fish → zooplankton → large fish
Which outcome would most likely occur if a food chain had more than five trophic levels?
Energy transfer would be 100 percent
Producers would increase indefinitely
Residual energy would be insufficient
Decomposers would disappear from system
Which of the following is not a producer?
Spirogyra
Nostoc
Agaricus
Volvox
Among the following, where would the process of decomposition be the fastest?
Tropical rain forest
Antarctic
Alpine region
Dry arid region
How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?
1%
90%
10%
40%
Increased concentration of DDT in fish-eating birds is due to
cultural eutrophication
bio-magnification
accelerated eutrophication
eutrophication
Assertion (A): Energy always flows from the Sun to producers. Reason (R): No energy that is trapped into an organism remains in it forever. Choose the correct option.
Both A and R are correct and R explains A
Both A and R are correct but R does not explain A
A is correct but R is wrong
A is wrong but R is correct
Assertion (A): Decomposition process is slower if detritus is rich in lignin and cutin. Reason (R): Decomposition is largely an oxygen requiring process. Choose the correct option.
Both A and R are correct and R explains A
Both A and R are correct but R does not explain A
A is correct but R is wrong
A is wrong but R is correct
Which factor primarily affects the rate of decomposition in a terrestrial ecosystem?
Availability of nitrates only
Nature of detritus and temperature
Amount of solar radiation
Presence of large herbivores
Humus formed during decomposition has which important feature?
Short-lived and transparent layer
Highly stable and dark material
Purely inorganic crystalline compound
Bright colored and volatile fraction
What is the key difference between grazing food chain and detritus food chain?
Uses carnivores versus omnivores
Starts with producers versus detritus
Includes parasites versus decomposers
Operates in oceans versus forests
In Sweden’s age pyramid, what pattern best describes the distribution?
Broad base with high birth rate
Top-heavy with extremely old population
Near-rectangular with low birth rate
Highly skewed male-to-female ratio
In Rwanda’s age pyramid, which feature indicates population growth trend?
Wider top than middle
Uniform width across ages
Equal percentages in elderly groups
Broad base and narrow top
Comparing Sweden and Rwanda, which statement about population structure is most accurate?
Sweden has higher infant percentage than Rwanda
Both show declining growth with narrow bases
Rwanda shows aging population like Sweden
Sweden shows stable growth; Rwanda shows rapid growth
Which age group in Sweden has approximately 3.6% for males and 3.6% for females?
35–39 years
45–49 years
25–29 years
15–19 years
Which term refers to the rate at which biomass is produced by autotrophs in an ecosystem?
Tertiary trophic transfer rate
Secondary consumer assimilation rate
Net ecosystem respiration rate
Gross primary productivity rate
Which unit is most appropriate for expressing primary productivity over time?
mL L−1 min−1
kJ m−2 yr−1
g mL−1 day−1
m s−2 month−1
According to the 10% law, what fraction of energy is typically transferred from one trophic level to the next?
About one-tenth of the energy
About one-half of the energy
About one-fourth of the energy
About nine-tenths of the energy
Why can an ecological pyramid based on numbers be misleading for a food web?
It cannot show trophic levels
It always overcounts producers
It ignores energy units
It ignores biomass differences
Which statement best explains low primary productivity in an arid region compared to a tropical region?
Stronger winds always increase respiration
Greater soil nitrogen always reduces growth
Higher herbivore density reduces producers
Lower water availability limits photosynthesis
A broad base in an age pyramid of a population indicates what demographic trend?
Low birth rate and stable size
Balanced immigration and emigration
High birth rate and rapid growth
High death rate in older ages
Which trophic level directly consumes primary producers?
Quaternary consumers
Tertiary consumers
Secondary consumers
Primary consumers
Which organisms commonly occupy more than one trophic level in an ecosystem?
Omnivores feeding on plants and animals
Obligate carnivores feeding on deer
Detritivores feeding on leaf litter
Strict herbivores feeding on grasses
Earthworms, mushrooms, soil mites, and dung beetles share which ecological role?
Detritus processing and decomposition
Obligate parasitism on producers
Primary production via photosynthesis
Top predation on tertiary consumers
In the diagram, DDT concentration increases from water to fish-eating birds. What term best describes this increase across trophic levels?
Bioaccumulation only within producers
Biological dilution through food chains
Biological magnification across trophic levels
Biodegradation by top consumers
Which process most directly causes higher DDT levels in fish-eating birds than in large fish?
More rapid metabolic breakdown of DDT
Lower lipid storage in birds
Consumption of many contaminated prey items
Direct absorption of DDT from water
What is the most likely physiological effect on fish-eating birds exposed to 25 ppm DDT?
Accelerated growth and larger body size
Eggshell thinning and reproductive failure
Enhanced immune resistance to pathogens
Improved thermoregulation in cold climates
Identify the correct trophic sequence shown in the diagram from I to V.
Water → zooplankton → small fish → large fish → fish-eating birds
Water → small fish → zooplankton → large fish → fish-eating birds
Water → zooplankton → large fish → small fish → fish-eating birds
Water → fish-eating birds → large fish → small fish → zooplankton
