Biology by Bradford
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The subtopic in the middle and ten tasks round it: label four diagrams, complete two tables, put a process in order and fill 46 gaps. Every box is standard level. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.
A is the place where an organism, population, species or community lives. A full description gives its location (the part of the world), its physical location and the type of : the common limpet lives on rocky shores of north-west Europe, clinging to rocks between high and low tide.
Mangrove swamps fringe tropical coasts. Their mud is waterlogged, so it holds little , and the water is . Red mangrove (Rhizophora mangle) stands on arching roots that brace it in soft mud, and its seeds germinate while still on the tree. Grey mangrove (Avicennia marina) takes in air through roots that grow up out of the mud, and gets rid of excess salt through on its leaves.
| Factor | Needed for reef growth | Why it matters |
|---|---|---|
| Water depth | shallow, mostly less than 50 m | the algae living in the coral need for photosynthesis |
| Clarity | clear water, low | suspended sediment blocks light and smothers the polyps |
| Temperature | , about 23 to 29 °C | growth slows in colder water; hotter water stresses the corals |
| Salinity | close to that of the open sea | reefs are absent near river mouths, where dilutes the sea |
| pH | slightly , about 8.2 | calcium carbonate skeletons are laid down more easily |
A is a group of ecosystems with similar communities, found wherever the abiotic conditions, above all the climate, are alike. Unrelated species in the same biome on different continents often look similar through : American cacti and African euphorbias both have swollen green stems that store water. Tundra is cold all year over permanently frozen ground; taiga has long freezing winters, and much of its precipitation falls as .
Marram grass (Ammophila arenaria) holds coastal , where rain drains away fast and the wind is drying. In dry air its leaves roll up, trapping air so less water is lost by . When blown sand buries it, underground stems called grow up through the sand, and its roots grow long and deep to reach water far below.
Number the steps in order.
Placing the quadrats at fixed intervals avoids . A strong correlation suggests a link, but on its own it does not prove .
| Species | Adaptation | How it helps |
|---|---|---|
| Saguaro cactus, hot desert | leaves reduced to ; stomata open only at | little water is lost: no broad leaves, and gas exchange happens when it is cool |
| Fennec fox, hot desert | very large, thin | radiate body heat; also pick up prey moving under the sand |
| Kapok tree, tropical rainforest | wide at the base of the trunk | hold up a very tall tree rooted in shallow soil |
| Spider monkey, tropical rainforest | a long tail that grips | a fifth limb for climbing and hanging in the canopy |
Many rainforest leaves end in a pointed that sheds rainwater quickly.
Abiotic variables such as temperature, light intensity and soil pH for a plant, or temperature and dissolved oxygen for an animal, affect where a species is found. A variable that goes beyond what the species can survive is the , setting the edge of its .
For any pattern of temperature and rainfall, one type of natural is likely to develop. Where it is too dry for forest but wetter than desert, the result is .
1234A habitat is the place where an organism, population, species or community lives. A full description gives its geographical location (the part of the world), its physical location and the type of ecosystem: the common limpet lives on rocky shores of north-west Europe, clinging to rocks between high and low tide.
Marram grass (Ammophila arenaria) holds coastal sand dunes, where rain drains away fast and the wind is drying. In dry air its leaves roll up, trapping humid air so less water is lost by transpiration. When blown sand buries it, underground stems called rhizomes grow up through the sand, and its roots grow long and deep to reach water far below.
Mangrove swamps fringe tropical coasts. Their mud is waterlogged, so it holds little oxygen, and the water is salty. Red mangrove (Rhizophora mangle) stands on arching roots that brace it in soft mud, and its seeds germinate while still on the tree. Grey mangrove (Avicennia marina) takes in air through roots that grow up out of the mud, and gets rid of excess salt through salt glands on its leaves.
Abiotic variables such as temperature, light intensity and soil pH for a plant, or temperature and dissolved oxygen for an animal, affect where a species is found. A variable that goes beyond what the species can survive is the limiting factor, setting the edge of its distribution.
Placing the quadrats at fixed intervals avoids bias. A strong correlation suggests a link, but on its own it does not prove causation.
| Factor | Needed for reef growth | Why it matters |
|---|---|---|
| Water depth | shallow, mostly less than 50 m | the algae living in the coral need light for photosynthesis |
| Clarity | clear water, low turbidity | suspended sediment blocks light and smothers the polyps |
| Temperature | warm, about 23 to 29 °C | growth slows in colder water; hotter water stresses the corals |
| Salinity | close to that of the open sea | reefs are absent near river mouths, where fresh water dilutes the sea |
| pH | slightly alkaline, about 8.2 | calcium carbonate skeletons are laid down more easily |
For any pattern of temperature and rainfall, one type of natural ecosystem is likely to develop. Where it is too dry for forest but wetter than desert, the result is grassland.
A biome is a group of ecosystems with similar communities, found wherever the abiotic conditions, above all the climate, are alike. Unrelated species in the same biome on different continents often look similar through convergent evolution: American cacti and African euphorbias both have swollen green stems that store water. Tundra is cold all year over permanently frozen ground; taiga has long freezing winters, and much of its precipitation falls as snow.
| Species | Adaptation | How it helps |
|---|---|---|
| Saguaro cactus, hot desert | leaves reduced to spines; stomata open only at night | little water is lost: no broad leaves, and gas exchange happens when it is cool |
| Fennec fox, hot desert | very large, thin ears | radiate body heat; also pick up prey moving under the sand |
| Kapok tree, tropical rainforest | wide buttress roots at the base of the trunk | hold up a very tall tree rooted in shallow soil |
| Spider monkey, tropical rainforest | a long prehensile tail that grips | a fifth limb for climbing and hanging in the canopy |
Many rainforest leaves end in a pointed drip tip that sheds rainwater quickly.