Adaptation To Environment

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शिक्षकों के लिए: Adaptation To Environment (Biology, HL) के लिए इस्तेमाल के लिए तैयार लेसन स्लाइड्स, रिवीज़न नोट्स — इन्हें अपने लेसन में इस्तेमाल करें, या टॉपिक को एक इंटरैक्टिव क्लास एक्टिविटी की तरह चलाएं जिसे आपके शिक्षार्थी लाइव गेम की तरह खेलें।

लेसन नोट्स

Habitats

A habitat is the place where an organism lives.
A single habitat contains many species that together form a community.
Habitats can be described by their geographical location, e.g. polar habitat at the North and South Poles.
Habitats can also be described by ecosystem type, e.g. grassland habitat occurs as prairies in North America and savannahs in Africa.
A habitat can be described using both location and ecosystem type, e.g. North American grassland, Arctic polar habitat, Sahara desert, UK wetland.

Abiotic Factors

Abiotic factors are non-living factors that affect organisms within their habitat.
Examples include light intensity and wavelength, temperature, turbidity (cloudiness of water), humidity, soil or water pH, salinity, soil composition, and oxygen or carbon dioxide concentration.
Abiotic factors can act as limiting factors that restrict the growth of organisms and determine species distribution.
Each species has a range of tolerance: conditions are ideal at the optimum, but some variation can be tolerated.
Species are not found in areas where abiotic conditions fall outside their range of tolerance.
Species adapted to extreme conditions often have a wide range of tolerance and an environmental optimum that is higher or lower than average, e.g. marram grass has a lower optimum for water availability.
Extreme species thrive where competition is low but may do less well in moderate environments due to competition from species with average optima.
Abiotic factors interact to determine the distribution of a species.

Adaptations of a fennec fox

Adaptations to Abiotic Factors: Sand Dune Grass

Marram grass grows on sand dunes, where abiotic factors include low water availability, high salinity, and low nutrient levels.
Marram grass is a xerophyte — a plant adapted to survive in dry conditions.
Xerophytes face a steep concentration gradient between the inside of leaves and the surrounding dry air, causing rapid water loss by evaporation.
Low soil water availability means lost water is not easily replaced.
Marram grass leaves are rolled up to reduce exposure to wind and trap water vapour inside.
Stomata are sunken in pits and the inner leaf surface is covered in tiny hairs, both trapping water vapour.
A thick waxy cuticle on the outer surface reduces evaporation.

Adaptations to Abiotic Factors: Mangroves

Mangrove swamps are tropical, coastal habitats frequently submerged in sea water, with high salinity, low fresh water availability, and low oxygen availability.
Submerged roots cannot take in oxygen for respiration, so mangroves have aerial root systems that absorb oxygen from the air.
Red mangroves have prop roots that provide stability in unstable soil and shelter marine animals underwater.
Black mangroves have pneumatophores that grow vertically upwards out of water-logged soil.
Red mangrove cells prevent salt from entering their water-transport systems, allowing uptake of fresh water and preventing water loss by osmosis.
Black mangroves take in salt water and excrete excess salt through salt glands in their leaves.
Mangroves grow best at a salinity of 3–27 parts per thousand (ppt) but can survive in fresh water and up to 75 ppt.

Species Distribution: Skills

Distribution refers to where a species is found within an ecosystem.
A transect measures the change in species abundance along an environmental gradient, giving an estimate of distribution at different levels of an abiotic factor.
Sampling takes measurements from a small area to represent a larger area; it saves time and must be representative with a large enough sample size.
Transect types include continuous line transect (every species touching the tape is recorded), interrupted line transect (species recorded at regular intervals), continuous belt transect (quadrats placed end-to-end), and interrupted belt transect (quadrats at regular intervals).
Abiotic factors are measured with specialised equipment: thermometer (air temperature), rain gauge (rainfall), hydrometer (humidity), electronic oxygen sensor (dissolved oxygen), turbidity meter or Secchi disc (water clarity), light meter (light intensity), compass (site aspect), clinometer (slope incline), indicator solution (pH), and mass difference before and after drying (soil water content).
Kite diagrams show both distribution and abundance along a transect; the position along a central horizontal line shows distribution and the width of the kite shows abundance.
Additional sections can be added to a kite diagram to show changes in abiotic factors such as elevation or soil pH.

Coral Reef Formation and Distribution

Corals result from a symbiotic relationship between a coral polyp and zooxanthellae algae.
The polyp provides shelter and protection; the algae photosynthesise and produce carbon compounds such as carbohydrates.
Some coral polyps secrete calcium carbonate, which builds up in layers to form a hard outer structure; over time, deposits from thousands of individuals form a coral reef.
Reef-building corals are limited to the tropics and subtropics; non-reef-building species occur elsewhere.
Reef formation is limited by water depth, pH, salinity, water clarity, and temperature; corals have a narrow range of tolerance for all of these.
Corals need shallow water for light to reach zooxanthellae; low pH reduces carbonate ion availability for calcium carbonate formation; salinity must be 32–42%; water must be clear; temperature range is roughly 20–28 °C, with best growth above 23 °C.
Rising sea temperatures cause polyps to expel their algae symbionts, leading to coral bleaching.

Biomes and Their Distribution

A biome is a large community of plants and animals that has developed as a result of environmental factors.
Biomes occur over large geographical areas and are usually named after their dominant vegetation type, e.g. tropical rainforest biome.
Examples include temperate rainforest, tropical rainforest, temperate deciduous forest, boreal/coniferous forest (taiga), grassland, tundra, and desert.
Average temperatures and rainfall patterns are significant factors determining which biome develops.
Biome development can be plotted on a climograph with mean annual rainfall and temperature on the axes.
For any given temperature and rainfall pattern, a particular biome will develop, e.g. at 200 cm rainfall and 25 °C, tropical seasonal forest develops; at 300 cm and 15 °C, temperate rainforest; at 100 cm and 0 °C, taiga.
Climographs show distinct boundaries, but in reality there is a gradual shift between biomes; other variables such as soil type and animal grazing may also influence development.
Regions with similar abiotic factors contain the same biome, e.g. desert occurs in Africa, North and South America, and Australia.

Biome Climate Conditions and Community Features

Tropical forest: annual rainfall 2000–10 000 mm, temperatures consistently 20–25 °C; nutrient-poor soil, layered vegetation, high productivity, very high biodiversity.
Temperate forest: annual rainfall 750–1500 mm, seasonal but no extreme temperatures; fertile soil due to autumn leaf fall, dominant deciduous trees, high biodiversity.
Taiga (conifer forest): annual rainfall 300–900 mm with high snowfall, very short growing season, temperatures −40 to 20 °C; dominant coniferous trees, low productivity, few well-adapted species.
Grassland: annual rainfall 500–950 mm, dry and wet seasons, temperatures −20 to 30 °C; dominant grasses, low productivity, grazing animals and few top predators.
Tundra: annual rainfall 150–250 mm, dark winters and frozen soil, temperatures −50 to 18 °C; too little water, light, or warmth for trees, low productivity, hibernating or migrating animals.
Hot desert: annual rainfall less than 250 mm, hot days up to 49 °C and cold nights down to 0 °C; very low productivity, few well-adapted species.

Adaptations to Biomes

Adaptations are traits that increase survival chances in a specific environment and come about by natural selection.
Species in equivalent biomes in different parts of the world show similar communities due to shared abiotic factors and convergent evolution.
Similar selection pressures favour similar features, which become more common in populations by natural selection, even without recent common ancestry.
Saguaro cactus (hot desert): thick waxy cuticle reduces evaporation; spines instead of leaves reduce surface area for transpiration and reduce grazing; expandable stem cells store water; deep tap root and shallow surface roots access and absorb water.
Kangaroo rat (hot desert): spends daylight hours in underground burrows to avoid high temperatures; extracts water from its diet and produces highly concentrated urine, going without drinking water for extended periods.
Kapok tree (tropical rainforest): rapid growth allows it to outcompete others and reach sunlight; wide buttress roots provide a sturdy base for rapid growth.
Orchid mantis (tropical rainforest): adult female resembles an orchid flower, attracting insect pollinators as prey — an example of mimicry; the smaller, plainer male camouflages among stems and branches.

Camouflage as an adaptation

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साइन अप करें — फ्री लॉग इन

प्रैक्टिस सवाल

फ्री प्रीव्यू — 61 में से 8 सवाल। सभी देखने के लिए साइन अप करें।

1.Which option correctly lists some abiotic features of an ecosystem?
Easy
- AMineral ions, light intensity, temperature
- BCompetition, predation
- CpH, producers, mineral ions
- DWind speed, decomposition, mineral ions
2.Which of the statements about the term habitat is/are correct? I. A habitat is the place where a community of organisms lives II. A habitat is the place where an individual organism lives III. Habitats can only be described in terms of their geographical location
Easy
- AI and II only
- BII only
- CII and III only
- DI, II and III
3.Which of the statements about biomes is correct?
Medium
- ABiome distribution is affected primarily by biotic factors.
- BFor any given temperature and rainfall pattern there are a range of ecosystem types that can develop.
- CA tropical rainforest biome will have high annual rainfall and low levels of biodiversity.
- DAverage temperatures and rainfall patterns are significant factors in determining the development of a biome.
4.Which of the following is a hazard to consider in a risk assessment when measuring abiotic factors in a natural environment?
Medium
- AUneven ground.
- BSlipping on wet rock.
- CCutting oneself on a sharp rock.
- DBreaking an ankle by falling over.
5.How could levels of dissolved oxygen in a pond be measured?
Medium
- ApH indicator
- BTurbidity meter
- CElectronic sensor
- DClinometer
6.Which of the following statements about adaptations to abiotic factors is correct?
Medium
- ASome grasses are able to release chemicals that attract the predators of insect herbivore species.
- BSome grasses are adapted to increase the water vapour concentration gradient between their leaves and the surrounding air.
- CMangroves are adapted to survive in an environment with limited fresh water availability.
- DMangroves deal with low oxygen availability by absorbing oxygen from the atmosphere via their stomata.
7.Which row correctly describes an example of an adaptation for survival in the given biome?
Medium
- ATropical forest - Thick waxy cuticles on leaves
- BTemperate forest - Nocturnal behaviour
- CTaiga - Wide buttress roots
- DHot desert - The ability to extract water from food
8.A habitat is the place where an organism lives.
Easy
True or false?

और सवाल

9.Species will be found in areas with abiotic conditions that are outside their range of tolerance.
Easy
True or false?
10.Which of the following are abiotic factors that can affect species distribution? (select all that apply)
Medium
- ASoil pH
- BCompetition for food
- CWind speed
- DPredation
- EOxygen concentration
11.Which of the following statements about mangroves are correct? (select all that apply)
Medium
- ARed mangroves have prop roots that provide stability in unstable soil.
- BBlack mangroves have pneumatophores that grow vertically upwards out of water-logged soil.
- CMangrove roots lose water by osmosis because sea water has a lower solute concentration than the root cells.
- DRed mangroves have cells that prevent salt entering their water-transport systems.
- EMangroves absorb oxygen through their stomata when submerged.
12.Match each abiotic factor to the method used to measure it.
Medium
- Air temperature
- Slope incline
- Water turbidity
- Humidity
- Thermometer
- Clinometer
- Secchi disc
- Hydrometer
13.Place the following biomes in order of increasing annual rainfall, starting with the lowest.
Medium
- Hot desert
- Tundra
- Grassland
- Temperate forest
- Tropical forest
14.Match each abiotic factor with the method used to measure it.
Medium
- Air temperature
- Rainfall
- Humidity
- Water turbidity
- Slope incline
- Thermometer
- Rain gauge
- Hydrometer
- Secchi disc
- Clinometer
15.Which of the statements about the data is correct?
Medium
- AThe data could have been collected using random quadrat sampling.
- BConditions are outside the range of tolerance for the invertebrates at >15 m from the waterline on beach 3.
- CThe number of invertebrates decreases as distance from the waterline increases.
- DConditions are at their optimum for the invertebrate species at around 9 m from the waterline.
16.Which of the following is an example of a behavioural adaptation to a hot desert environment?
Medium
- AThick waxy cuticle on leaves
- BSpending daylight hours in underground burrows
- CHaving wide buttress roots
- DProducing highly concentrated urine
17.Which of the following are adaptations of marram grass to its sand dune habitat? (select all that apply)
Medium
- ARolled leaves
- BSunken stomata in pits
- CThick waxy cuticle
- DWide buttress roots
- EAerial roots
18.Which of the following is an abiotic factor?
Medium
- APredation
- BCompetition
- CSoil pH
- DFood availability
19.Which of the following best describes the term 'distribution' in ecology?
Medium
- AThe number of individuals in a population
- BWhere a species is found within an ecosystem
- CThe variety of species in a habitat
- DThe interactions between organisms
20.Which of the following are adaptations of mangrove trees to high salinity? (select all that apply)
Hard
- ASalt glands in leaves
- BProp roots
- CCells that prevent salt entry
- DPneumatophores
- EThick waxy cuticle
21.Which of the following is a biotic factor?
Medium
- ATemperature
- BLight intensity
- CPredation
- DSoil salinity
22.What is the primary reason that coral reefs are limited to tropical and subtropical waters?
Medium
- AThey require high salinity
- BThey require shallow water for light penetration
- CThey require low pH
- DThey require strong water currents
23.Which of the following is an example of a structural adaptation of a hot desert plant?
Medium
- ANocturnal behaviour
- BExtracting water from food
- CSpines instead of leaves
- DProducing concentrated urine
24.In a climograph showing biome distribution, what does a point at mean annual rainfall of 100 cm and mean annual temperature of 0 °C represent?
Medium
- ATropical seasonal forest
- BTemperate rainforest
- CTaiga (boreal forest)
- DHot desert
25.Which of the following statements about the distribution of biomes is correct?
Medium
- ABiome distribution is primarily affected by biotic factors.
- BFor any given temperature and rainfall pattern, a range of ecosystem types can develop.
- CA tropical rainforest biome will have high annual rainfall and low biodiversity.
- DAverage temperatures and rainfall patterns are significant factors in determining biome development.
26.Which of the following is an example of a physiological adaptation to a hot desert environment?
Medium
- AThick waxy cuticle
- BSpending daylight hours in burrows
- CProducing highly concentrated urine
- DHaving wide buttress roots
27.Which of the following are adaptations of the saguaro cactus to its desert environment? (select all that apply)
Hard
- AThick waxy cuticle on the stem
- BSpines instead of leaves
- CWide buttress roots
- DCells in the stem that can expand to store water
- EAerial roots
28.The distribution of reef-building corals is limited to the tropics and subtropics.
Easy
True or false?
29.Marram grass is a xerophyte.
Easy
True or false?
30.Which of the following statements about transects is correct?
Medium
- ATransects are used to measure species abundance in a single spot.
- BTransects are lines laid out across a site to measure abundance and distribution along an environmental gradient.
- CTransects are only used in marine habitats.
- DTransects require random sampling.
31.Which of the following is an abiotic factor that affects coral reef formation?
Medium
- ACompetition with other corals
- BPredation by fish
- CWater clarity
- DSymbiotic relationships
32.Which of the following are examples of adaptations to low water availability in plants? (select all that apply)
Hard
- ARolled leaves
- BSunken stomata
- CThick waxy cuticle
- DAerial roots
- ESalt glands
33.Place the following steps in the correct order to carry out an interrupted belt transect.
Medium
- Lay out a tape measure along the environmental gradient.
- Place a quadrat at the start of the transect.
- Record the species and their abundance in the quadrat.
- Move the quadrat to the next regular interval along the tape.
- Repeat recording at each interval along the transect.
34.Match each biome with its characteristic feature.
Medium
- Tropical forest
- Temperate forest
- Taiga
- Grassland
- Tundra
- Hot desert
- High biodiversity and nutrient-poor soil
- Fertile soil due to leaf fall
- Dominant coniferous trees
- Dominant grasses and grazing animals
- Hibernating or migrating animals
- Very low productivity due to lack of water
35.A student measures the salinity of water in a mangrove swamp and finds it is 85 parts per thousand (ppt). Based on the range of tolerance for mangrove trees, which statement best describes the likely distribution of mangroves at this location?
Medium
- AMangroves will be absent because the salinity is above their critical maximum.
- BMangroves will be abundant because they prefer high salinity.
- CMangroves will be present but will grow more slowly.
- DMangroves will be present but will have a lower optimum salinity.
36.A climograph shows that a particular location has a mean annual rainfall of 800 mm and a mean annual temperature of 18 °C. According to the climograph, which biome is most likely to develop there?
Medium
- ATaiga
- BTemperate forest
- CTropical rainforest
- DTundra
37.A scientist is investigating the effect of water depth on the distribution of non-motile marine organisms. Which of the following methods would be appropriate for collecting data on non-motile species along a depth gradient? (select all that apply)
Hard
- AUsing a quadrat placed on the sea bed at different depths.
- BUsing a transect line with quadrats at regular intervals.
- CUsing a net to catch fish at different depths.
- DUsing a Secchi disc to measure water clarity.
- EUsing a clinometer to measure the slope of the sea bed.
38.Corals can only grow at shallow depths where light can penetrate the water at high enough levels for the zooxanthellae to photosynthesise.
Medium
True or false?
39.Match each abiotic factor with its effect on reef-building coral.
Medium
- Water depth
- pH
- Salinity
- Temperature
- Corals need carbonate ions to build calcium carbonate; low pH reduces their availability.
- Corals have a range of tolerance of roughly 20–28 °C, though they grow best above 23 °C.
- Corals can only grow where light can penetrate for the zooxanthellae to photosynthesise.
- Corals are marine animals that need salty water within a 32–42 % range.
40.A student is investigating the effect of soil water content on the distribution of a plant species across a sand dune. Which of the following would give the most valid measurements of the abiotic factor along the transect?
Medium
- ARecord the difference in mass between a soil sample and the same soil sample after it has been dried
- BMeasure the pH of the soil at each sample point using indicator solution
- CUse a Secchi disc lowered into the soil until it is no longer visible
- DRecord the slope incline at each sample point using a clinometer
41.Reef-building corals have a range of tolerance for temperature of roughly 20-28 °C, though they grow best above a certain temperature. State the temperature above which corals grow best, in °C.
Medium
42.Complete the definition of a biome.
Easy
A biome is a large ____ of plants and animals that has developed as a result of environmental factors.
43.Name the group of plants that are adapted to survive in dry conditions, such as marram grass.
Easy
44.Reef-building corals have a range of tolerance for temperature of roughly 20–28 °C, though they grow best above a certain temperature. State the temperature above which they grow best.
Medium
45.What is the term for the range of environmental conditions within which a species can survive?
Medium
46.Name the type of diagram that can show both the distribution and abundance of species along a transect.
Medium
47.Complete the sentence about coral reef formation.
Medium
Corals are the result of a symbiotic relationship between a coral polyp and ____ algae.
48.Complete the sentence about mangrove adaptations.
Medium
Black mangroves have vertical roots called ____ that grow upwards out of water-logged soil.
49.Mangrove trees grow best in a salinity range between 3 and 27 parts per thousand (ppt), but they can survive in salt concentrations of up to a certain level. State this maximum salinity in ppt.
Medium
50.What is the term for a factor that restricts the growth of organisms and determines their range of tolerance?
Medium
51.What is the term for the process by which similar adaptations arise independently in different species facing similar selection pressures?
Medium
52.A mangrove swamp has a salinity of 40 parts per thousand (ppt). What is the percentage salinity?
Hard
53.State two adaptations that you would expect marram grass to have in order to aid survival on sand dunes.
Medium
54.State three abiotic factors acting on mangrove trees in this habitat.
Medium
55.Identify one adaptation of mangrove trees and explain how it aids survival.
Medium
56.Explain how climate change may affect the distribution of mangrove habitat.
Hard
57.Explain why desert biome species share similar features despite living in different parts of the world.
Hard
58.Reef-building corals have a range of tolerance for temperature of roughly 20-28 °C, though they grow best above a certain temperature. State the temperature above which corals grow best, in °C.
Medium
- A21 °C
- B25 °C
- C23 °C
- D27 °C
59.Reef-building corals have a range of tolerance for temperature of roughly 20–28 °C, though they grow best above a certain temperature. State the temperature above which they grow best.
Medium
- A27 °C
- B23 °C
- C21 °C
- D25 °C
60.Mangrove trees grow best in a salinity range between 3 and 27 parts per thousand (ppt), but they can survive in salt concentrations of up to a certain level. State this maximum salinity in ppt.
Medium
- A75 ppt
- B91 ppt
- C67 ppt
- D83 ppt
61.A mangrove swamp has a salinity of 40 parts per thousand (ppt). What is the percentage salinity?
Hard
- A4 %
- B5 %
- C3 %
- D6 %

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