IB Biology SL B4.1 Adaptation to environment Question Bank

Three-toed sloths (Bradypus variegatus) are placental mammals that live in trees in Central and South America. They eat leaves and fruit and get almost all their water from succulent plants.

Three-toed sloths change their body posture in response to the temperature of their environment (ambient temperature). Researchers assessed posture on a scale from 1 to 6 , with 1 being when the sloth was curled into a tight ball and 6 when it had all limbs spread. The percentage of time the sloths were observed in each position was recorded at ambient temperatures from $22^{\circ} \mathrm{C}$ to $34^{\circ} \mathrm{C}$. The researchers also measured the body temperature of the sloths over the same range of ambient temperatures.

Posture

Fires are a natural phenomenon in some forest ecosystems, so plants evolve to become fire-adapted. The Northern Jarrah Forest in southwest Australia is an example. The seeds of many species germinate after forest fires, when there is less competition for resources from existing plants.

The effect of temperature on germination was measured in species that occur commonly in the Northern Jarrah Forest. The graphs show results for eight species across the range of soil temperatures expected in this ecosystem. Four replicates of 25 seeds were sown at each temperature. Statistical modelling was used to predict the overall relationship between temperature and germination, and to estimate the optimum temperature ( $\mathrm{T}_{\text {opt }}$ ) and maximum temperature ( $\mathrm{T}_{\max }$ ) at which germination commonly occurs. The eight species were then divided into two groups according to the effects of temperature on germination.

Bottlenose dolphins (Tursiops truncatus) inhabit almost all tropical and temperate oceans between $45^{\circ} \mathrm{N}$ and $45^{\circ} \mathrm{S}$. Over a two-year period, aerial surveys were carried out to investigate the seasonal distribution of these animals along the mid-Atlantic and eastern coastal waters of the USA. Sightings were recorded using a global positioning system (GPS) while flying parallel to the coast approximately 500 m offshore. The diagram below shows a map of the section of coast surveyed. The bar graph shows the seasonal data for summer and winter at the corresponding latitudes ( ${ }^{\circ} \mathrm{N}$ ). A total of 5431 bottlenose dolphins were sighted during these surveys.

Beavers are large rodents that live in waterways throughout the northern hemisphere. Dams made by beavers change the temperature of the streams and affect the mayfly, Baetis bicaudatus. In the summer of 2008, beaver ponds in West Brush Creek and Cement Creek, Colorado, were studied to evaluate their impacts on mayflies. The study sites included streams flowing into (upstream) and out of (downstream) each beaver pond.

Mayflies, including the species B. bicaudatus, are aquatic insects that hatch and spend their larval stages in water emerging from the water as adults. Larger females produce an increased number of better quality eggs.

The image shows a cast of the lower surface of a leaf from a busy Lizzie (Impatiens walleriana) plant as seen under a light microscope with a magnification of $600 \times$.

The distribution of native grasses in a temperate arid region of Mendoza, Argentina, was studied in six habitats (I to VI) at different altitudes. The table shows the presence (+) or absence (-) of the species in each habitat.

A graph of abiotic factors needed for biomes to develop is shown. Which label identifies temperate forest?

What is an abiotic factor in an ecosystem?

Avicennia officinalis is a tree species that is adapted to live in mangrove swamps. Salt glands can be seen in the micrograph of a transverse section of an A. officinalis leaf.

How does A. officinalis benefit from this adaptation?

The desert cottontail (Sylvilagus auduboni) is a rabbit that lives in North American deserts.