Test 3 Review Flashcards
What is the difference between taxonomic and physiognomic classifications? Can you provide an example of each? Can you recognize each when an example is given?
Physiognomic classifications refer to the physical features of the plant, while taxonomic ones refer to a plant’s evolutionary lineage. The category of needle-leaved plants is a physiognomic one, based on the physical characteristics of the plant. Although the many plants that fall into the category of needle-leaved may have very similar appearances, they may be only distantly related to one another, having evolved similar features through convergent evolution. A taxonomic classification would be the Linnaeus system of classification that we now use to categorize species into related groups, using higher-up groups like kingdom, phylum, class, order, family, and genus. For example, the genus of the domestic cat is Felis, and its species epithet is catus - giving it the name Felis catus. Other related animals, like medium-sized cats, are also in the Felis genus but have different species epithets.
Can you describe, define, and recognize the layers of vegetation in the forest?
There are four layers typically defined in forests: the bottom-most layer is the moss layer, where we find thallophytes, which is on the forest floor. The next layer up is the herb layer, which grows taller than the moss layer and has herbaceous plants like graminoids and forbs, which are not woody. Next up is the shrub layer, where we find shrubs, which are woody plants that branch close to the ground. Finally, the layer with plants that grow the tallest is the tree layer, where we find trees - woody plants with a main stem that grows up high before branching out and making leaves and foliage.
Can you define and differentiate between: trees, shrubs, liana, herbaceous, forb, graminoid, epiphytes, and arboreal plants?
Trees and shrubs both have woody stems, but trees have a trunk and the foliage is raised above this thick, woody trunk, while with shrubs the branching and foliage are near the ground. Herbaceous plants lack woody stems and are generally shorter than trees. The category of herbs can be further divided into graminoids and forbs. Graminoids are grasses, sedges and rushes; they have parallel venation. Forbs have dendritic, or webbed, venation. Liana is another word for vine; these plants are rooted in the ground and use things like buildings or other plants for support. Epiphytes are like lianas, except they are not rooted in the ground. Lianas and epiphytes are generally not detrimental to their hosts. Finally, the arboreal category can be used to define both plants that grow to the size of trees, like with Papyrus being an arboreal graminoid, or it can be used to describe plants whose habitats are on trees, like epiphytes.
Can you define and differentiate between broadleaf vs needle leaf plants?
Broadleaved plants have leaves that are typical of what we think of when we think of leaves - maple trees, for example, are broad-leaved trees. Needle-leaved trees have “leaves” that have evolved into needles, since this is structurally beneficial for withstanding the weight of snow and for conserving energy, as these trees do not have to spend energy regrowing all their leaves each year in the spring. An example would be a spruce tree.
Can you define and differentiate between deciduous vs evergreen plants?
Deciduous plants lose their leaves in response to conditions that do not favour photosynthesis as a measure to conserve energy, for example during the winter, or in the arctic when there is very little daylight some parts of the year. Evergreen plants do not lose their leaves or leaf equivalents.
Can you define and differentiate between annual and perennial plants?
Annual plants die out on a yearly basis, usually when winter arrives, and they reappear in the spring when the seeds they leave behind begin to grow. To contrast, perennial plants can survive the winter on an individual basis, with the same plant surviving through winter and regrowing when spring comes. Perennial plants sometimes grow out of bulbs in the ground.
Can you define and differentiate between forests and woodlands?
In a forest, the crowns of the trees overlap, giving a full and thick canopy cover. In a woodland, this is not the case - trees are far enough apart, or have small enough crowns, that the crowns do not overlap, and there are areas of shrub activity where there are no trees to hog the light.
Where does water enter a plant? Where is it lost?
Water enters the plant from its roots, after which it is transported through the vascular system up to the leaves, where it plays an important role in photosynthesis. Water is primarily lost in vapour form through the stomata of the plant’s leaves.
What strategies (adaptations) help plants reduce water loss?
Since leaves are the major site of gas exchange in plants and most water is lost as vapour due to gas exchange, most adaptations that conserve water involve leaves somehow. In the desert,
What is a thallophyte?
Thallophytes are plants that have singular, undifferentiated bodies, like lichens, liverworts, and mosses. This category exists in opposition to cormophytes, which have differentiated bodies, meaning their bodies can be divided into distinct parts, like the roots, stems, leaves, et cetera.
How would you characterize a xerophytic plant?
Xerophytes are plants that have adapted to conditions where there is very little water. These plants often have either no leaves - having spines instead - or their leaves (or other structures) have evolved thick, waxy coatings and fleshy insides to help them minimize evapotranspiration and conserve and store water. Some xerophytes have even more specific adaptations, like long and thick roots that allow them to absorb groundwater, or an adaptation to the way they fix carbon dioxide that allows them to open their stomata only at night, when evapotranspiration will be low (CAM plants).
How (generally) goes temperature affect plants?
As a general trend, as temperature decreases, the productivity of plants decreases. We see the highest rates of plant activity in warm, moist environments near the equator. We see the least in the cold and dry arctic environments of the poles.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 1: Desert (both warm and cold)
Desert environments are characterized by very low levels of precipitation. They can be hot deserts, like the sahara, or cold deserts, like those in the arctic. Due to a lack of regularly decaying organic matter, soils are often poorly developed, with little organic content and a very thin organic horizon. Since organic matter provides a dark colour to soils, the soils in arctic deserts are often a characteristic brown. In a cold desert, the thin organic horizon may also be attributed to the presence of permafrost. Typically, vegetation is sparse, small, slow-growing, and well spread out to minimize competition for the limited moisture available.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 2: tropical rainforest
Tropical rainforests have the highest plant productivity of any biome thanks to an excess of water and a fairly constant hot temperature suitable for plant growth. Soils are (strangely) not very well developed at all. They are known as oxisols. The high amounts of rainfall carry away organic matter and cause leaching. Plants generally get their nutrients from a very thin layer of ever-present decaying organic matter at the forest floor. Plants have the opportunity to grow very large due to no lack of water (no need to limit leaf size to conserve moisture) or nutrients, and this enables them to compete for sunlight, creating a dense canopy.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 3: boreal (needleleaf) forest
The boreal forest is often found in subarctic environments, like northern Canada. Temperatures vary throughout the year, and the region likely has very cold winters and cool summers. Precipitation is moderate throughout the year. The soils here are called podzols, and they have moderately thick active layers and are often subject to bleaching in lower soil horizons. The turnaround time for decomposition of organic matter in these soils is very slow, and a low nutrient content makes it hard for new plants to grow. Due to the cold climate, there may be discontinuous permafrost in this biome.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 4: mid-latitude broadleaf and mixed forest
This biome describes southern Ontario and Quebec, including Montreal. Here, there are cold winters and hot summers, and a moderate amount of precipitation throughout the year. The soils here are brunisols, which are not highly developed, but have a thicker organic layer and a faster organic matter decomposition turnaround time when compared to boreal forests due to greater temperature variability. Both of these features of the soil enable it to support a wider variety of plant life, leading to the development of mixed deciduous and coniferous forests.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 5: prairie/grassland (tall and short grass)
Owing to the versatility of graminoids, grasslands can be found all over the world in a diverse set of conditions. The archetypal grassland is seen in the midwestern US and Canada, in the great plains. Here, the soils (known as chernozems, or mollisols) are especially fertile, although precipitation can be lower than in other regions. Temperatures are similar to mixed forest environments, with cold winters and hot summers. The environment lends itself well to the development of woodlands and shrublands. However, periodic drought (“dry seasons”) prevents significant forest development. Short grass prairie is found at the west end of the great plains, where they meet the rockies, and there is less rainfall and soil is less fertile.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 6: mediterranean shurbland
This biome is typically semi-arid, with little precipitation and cool to hot temperatures. Plants here have adapted to the lack of moisture in the hot summers by evolving small, hard leaves with thick cuticles. The soils here are known as terra rossa, and they live up to their name with a brilliant red colour. This biome can be found around the mediterannean sea, but also in portugal, california, australia, and other places.
Can you describe and compare the basic climate, vegetation, and soil differences of the following biomes, highlighting the DIFFERENCES AMONG them AND INDICATING where they are on a map of the world? Biome 7: tundra
Tundra is often found in the northern subarctic, and it is typically cold and semi-arid. Due to low levels of vegetation and low moisture availability, trees do not thrive here as they do in the subarctic boreal forest. Typically, we see some graminoids and forbs that have adapted to low moisture and cold temperatures, while trees are rare and are generally remnants of now-dead forests that are just surviving. This zone is between boreal forest and the arctic desert.
What strategy/ies for avoiding moisture stress is/are typical of the mediterranean shrubland?
The vegetation in the mediterannean region is often described as sclerophyllous, meaning they have hard leaves with a thick, waxy cuticle to keep in water that would otherwise be lost through evapotranspiration.
Can you describe the pattern of vegetation change on the North American continent from east to west at approximately 40degN latitude?
As we go inland on this trip, moisture becomes less and less available. Starting at the coast of rhode island, we encounter coastal estuaries, including salt marshes. These environments have water in abundance, lots of precipitation, and are warm. Slightly inland from the coast we see temperate mixed forests. The next biome we encounter is the oak savanna, where we find woodlands but not forests, due to the decrease in moisture availability. Next, we move into the prairies. In the first phase of the prairies we still see some forbs along with the grass, but as we progress westward we eventually move into steppe which is purely grassland. Finally, after this, we reach the desert.
How are transitions in vegetation communities with latitude and altitide similar? Why? Can you give examples of vegetation changes?
As you go up in latitude or altitude, temperatures decrease and precipitation tends to decrease, so the changes in vegetation and soils are similar. Going north from souther quebec to the arctic, we move from broad-leaf deciduous or mixed forest to boreal forest, to alpine tundra, to finally arctic desert. This same pattern is reflected as you go up a mountain.
Can you explain the difference between primary and secondary succession?
Primary succession occurs in response to catastrophic events that strip the soil from the land, like landslides, tornadoes, lava flows, et cetera. Secondary succession occurs in response to less extreme events that don’t affect the soils but remove vegetation cover, like forest fires, windstorms, or anthropogenic disturbance.
What environmental changes occur during succession?
Since old plant material is often removed, there is much more light available near the ground after the event that causes succession. In addition, there will be more water available on the ground, as precipitation will not be intercepted as much. Surface temperatures can change due to large changes in albedo. In primary succession, as most of the soil is stripped away, there are far fewer nutrients in the environment.
What is meant by the expression “climax vegetation”?
The climax community is a group of self-perpetuating species whose presence is persistent once established (i.e. they are not later replaced wholesale by other species).
How are some ecosystems “resistant” or “resilient” ?
A resistant ecosystem is resistant to change. A resilient ecosystem is good at recovering from unforseen change. For example, rainforest environments are quite resistant, able to withstand typhoons each year; however they are not very resilient, as their soils are poorly developed, and if they were destroyed by another force (e.g. clearcutting) they would not be able to recover.
What is a paradigm?
A set of concepts, results, and procedures upon which subsequent scientific work is based. A paradigm is disturbed when we gather too many anomalies that cannot be explained within its framework.
Can you provide a definition of niche?
The function or occupation of a lifeform in a given community, and the way it provides for its physical, chemical, and biological needs.
Can you draw a diagram of major carbon flows, including sinks and sources, storage, etc?
