Adaptation to Environment (DP IB Biology)
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1/40- FrontHabitats
Define the term habitat.
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Define the term habitat.
A habitat is the place in which an organism, species, population or community lives.
What information can be included in the description of a habitat?
A habitat can be described in terms of its:
geographical or physical location, e.g. North America or Arctic
ecosystem type, e.g. grassland or wetland
What is an abiotic factor?
Abiotic factors are non-living factors that affect organisms within their environment, such as light intensity, temperature and soil pH.
What is the main challenge faced by grasses that grow on sand dunes?
The main challenge faced by grasses living on sand dunes is a lack of water. Water drains away quickly in sand, so it is a challenge for the plants to avoid losing more water than they can take up from the sandy soil.
How are grasses that grow on sand dunes adapted to reduce water loss?
Grasses that grow on sand dunes, e.g. marram grass, are adapted to reduce water loss by having:
rolled leaves
sunken stomata in pits
tiny hairs on the inner surface of rolled leaves
a thick waxy cuticle
True or False?
Mangrove trees grow with their roots submerged in fresh water.
False.
Mangrove trees grow with their roots submerged in salt water.
What are the abiotic challenges faced by mangrove trees?
Mangrove trees face the following abiotic challenges:
high salinity means that there is a risk of losing water from their roots by osmosis
low fresh water availability
low oxygen availability
What adaptations do mangroves have for high salinity?
Mangrove adaptations to high salinity include:
cells that do not allow the entry of salt, allowing them to take up fresh water without disrupting their osmotic balance (red mangroves)
taking salt water into their cells and excreting excess salt through salt glands (black mangroves)
What adaptations do mangroves have for low oxygen availability?
Mangroves are adapted to low oxygen levels by having an aerial root system where the parts of the roots that are above the water take in oxygen; examples include:
prop roots (red mangroves)
pneumatophores that grow vertically upwards out of the water-logged soil (black mangroves)
What are some examples of abiotic factors?
Examples of abiotic factors include:
light intensity and wavelength
temperature
turbidity, or cloudiness, of water
humidity
soil or water pH
soil or water salinity
soil composition
oxygen or carbon dioxide concentration
What is the range of tolerance of a species?
The range of tolerance of a species is the range of environmental conditions within which it can survive.
True or False?
The adaptations of a species determine its range of tolerance.
True.
The adaptations of a species determine the range of environmental conditions that it can tolerate.
Define the term distribution in the context of species.
Distribution is where a species is found within an ecosystem.
Define the term limiting factor in the context of a species' range of tolerance.
A limiting factor is any biotic or abiotic factor that restricts the growth of organisms, so playing a role in determining a species' range of tolerance.
What is a transect?
A transect is a line laid out across a habitat, usually along an environmental gradient, along which abundance and distribution can be measured.
True or False?
It is necessary to measure all abiotic factors in a study that is investigating the effect of such factors on a species' range of tolerance.
False.
It is only necessary to record abiotic factors that are relevant to the study in question, e.g. in an investigation into soil moisture and species distribution, this is the only factor that would need to be measured.
What is a semi-natural habitat?
A semi-natural habitat is a habitat that has been influenced by human activities but that is still dominated by wild species rather than cultivated species.
What type of sensor would be used to measure air or water temperature in a habitat?
A thermometer would be used to measure air or water temperature in a habitat.
How would light intensity be measured in a habitat?
Light intensity in a habitat would be measured using an electronic light meter.
How would soil pH be measured in a habitat?
Soil pH would be measured using indicator solution, or an electronic pH meter.
What are corals?
Corals are structures that form as the result of a relationship between an animal known as a coral polyp, and a zooxanthellae algae.
What is the primary building material of coral reefs?
The primary building material of coral reefs is calcium carbonate, secreted by some species of coral polyps.
True or False?
Coral reefs can form in any ocean region.
False.
The distribution of reef-building corals is limited by abiotic factors, meaning that reefs only form in the tropics and subtropics.
Non-reef-building can be found in other locations.
What abiotic factors affect coral formation?
Abiotic factors that affect coral formation include:
water depth
pH
salinity
water clarity
temperature
How does pH affect coral reef formation?
pH affects coral reef formation by influencing the availability of carbonate ions needed for calcium carbonate formation; lower pH reduces coral growth.
What is the effect of water depth on coral reef formation?
Water depth affects coral reef formation as corals can only grow at shallow depths where light can penetrate for zooxanthellae photosynthesis.
Define the term biome.
A biome is a large community of plants and animals that has occurred as a result of environmental factors.
What are the two main factors affecting biome distribution?
The two main factors affecting biome distribution are:
average temperatures
rainfall patterns
What can be determined from the graph below?
The graph allows us to determine which type of biome will develop at any given mean annual rainfall and temperature. It is known as a climograph.
True or False?
On a graph of mean annual rainfall against mean annual temperature, temperature should always be plotted on the x axis.
False.
On a graph of mean annual rainfall against mean annual temperature, neither variable is the independent variable, so either variable can be plotted on either axis.
This means that you may come across different forms of this graph in an exam.
True or False?
Communities in equivalent biomes in different parts of the world contain the same species.
False.
Equivalent biomes contain similar communities, even if the species are not exactly the same.
What causes similarities between communities in equivalent biomes?
Similarities between communities in equivalent biomes exist due to shared abiotic factors and resultant convergent evolution.
How do the environmental conditions in a temperate forest biome differ from those of a tropical forest biome?
Abiotic conditions in a tropical forest biome can be compared with those in a temperate forest biome as follows:
Tropical forest
Temperate forest
high rainfall
lower rainfall
consistent temperatures all year round
seasonal temperatures
nutrient poor soil
fertile soil
What is taiga biome known for?
Taiga is a biome that contains coniferous forest with high snow fall and cold temperatures.
What are the abiotic conditions of a grassland biome?
Grassland biomes have medium levels of seasonal rainfall, and can occur over a wide range of temperatures.
True or False?
Tundra biomes have high productivity.
False.
Tundra biomes have low productivity due to a lack of water, light and warmth for tree growth.
What are the temperature conditions for hot desert biomes?
Hot desert biomes have hot days (up to 49 °C) and cold nights (down to 0 °C).
What adaptations might an animal that lives in a hot desert biome have?
Adaptations of animals in hot deserts might include:
digging burrows inside which they can keep cool during the day
the ability to gain water from food
the ability to reduce water lost in urine
True or False?
Plants that live in a hot desert biome are likely to have reduced leaves.
True.
Plants in hot deserts are likely to have reduced leaves as this reduces the surface area for water loss. E.g. cacti have leaves that are reduced to spines.
Why might a plant species in a tropical forest biome be adapted to grow quickly?
A plant in a tropical forest might be adapted to grow quickly as this increases its ability to outcompete other plants for light in a region of high productivity.