Habitat and Lifestyle PDF

TOPIC 2 Habitat and Lifestyle Everyone has special talents that make that person unique. What do you do better than anyone else in the class? Like people, some organisms do...

TOPIC 2 Habitat and Lifestyle Everyone has special talents that make that person unique. What do you do better than anyone else in the class? Like people, some organisms do some things better than others. Variation in people and other organisms is more than just physical appearance. It can also be what an organism does well. For example, dandelions grow well in bright sunlight, while ferns grow well in the shade. The Niche: What Makes an Organism Special? As you have seen, adaptations allow an organism to play a specific role Describe the niches of in its environment. Adaptations also help organisms to compete with three other organisms each other for the needs of life. You may remember from earlier studies found in Alberta. that an organism’s niche includes two parts: where an organism lives Describe at least one (its habitat) and what it does. Look at the poplar tree plant and one animal. in Figure 1.9. This poplar’s habitat is a mountain Write your answers in forest just outside of Banff. But what your Science Log. does the poplar tree do? What is its role? A poplar tree: absorbs light for photosynthesis removes carbon dioxide from the air and releases oxygen into the air provides food and shelter for a wide variety of organisms stabilizes the soil from erosion (wearing away) covers the ground with leaves in the fall, which returns nutrients back into the soil removes water and nutrients from the soil These various activities are what the poplar tree "does" and they make up its role in the ecosystem. Figure 1.9 This poplar tree performs many functions, which, together with its habitat, make up its niche. 16 MHR Biological Diversity Variation and Competition When resources such as food, water, or sunlight are plentiful, many species can share them. However, when any one of these resources becomes scarce, the organisms that depend on the resource must compete for it. Competition can occur between members of the same species or between different species. Whenever two individuals compete, variations between the individuals may give one of them an advantage. Again, this is true of members of the same or different species. For example, if two species, such as mule Hawaiian plants do not deer and white-tailed deer, are competing for the same resource, one may have thorns or toxins. have more favourable adaptations. Mule deer are able to tolerate cold Although pigs, goats, and winters much better than white-tailed deer. However, white-tailed deer deer have been intro- thrive near agricultural lands. Depending on the surroundings, the duced to the islands, there are no browsing members of one species may be faster or better able to avoid predators. mammals native to This would allow the better-adapted deer species to reproduce and Hawaii. As a result, native eventually “take over.” In order for future generations to survive, the plants did not evolve less successful species may have to change to a less desirable food adaptations for protection source or move to another habitat. from browsing mammals. in ok g Lo d A hea Think about what you would need to know about various species of trees and other plants in order to dis- Figure 1.10 These deer must compete with each other and with other species for food cuss the issue on and space. pages 82–83. Is there an advantage to Some species avoid competition with more dominant species by using a removing old trees? different food source or keeping different habits or behaviours. Cougar What effect might this hunt large herbivores like deer, elk, or bighorn sheep, and are usually action have on com- found in thick pine forests. Lynx can inhabit the same area as cougars, petition among other kinds of organisms on but tend to feed on snowshoe hare. Many owls avoid competing with the area? hawks by hunting at night. As organisms change to avoid or reduce competition, they alter their niches. These subtle changes eventually increase the variation within or between species. Habitat and Lifestyle MHR 17  Warblers are small, active birds with sharp beaks adapted for capturing insects. Numerous species of warblers can be found in Alberta during the summer. They winter in the southern United States and in Central and South America. In the spruce forests of Canada five warbler species can co-exist in the same tree: Cape May warbler feeds on insects at the top and tips of the tree. In your Science Log, Yellow-rumped warbler feeds on Cape May black- create a scenario that warbler throated would explain how the insects near the trunk’s lower green feeding habits of the branches and on the ground. warbler different warblers Black-throated green warbler feeds developed. near the middle of the tree. Blackburnian warbler feeds from Blackburnian the outer tips from the middle to warbler the top. Bay-breasted warbler feeds from the lower half of the tree away bay- yellow- from the tips. breasted rumped Explain why the diagram All of these birds live in the warbler warbler of the spruce tree does not show a completely same tree, but do they share the Figure 1.11 Which characteristics do all of accurate picture of the same niche? the warblers share? How are these birds warblers’ feeding pat- Animals are not the only organ- able to avoid competing with one another? terns. How could you isms that have very specific niches. design an experiment to Did you know that countless numbers of micro-organisms inhabit the get a more accurate pic- ture of what is happening? human body? You could say that each part of your body is its own Write your thoughts in ecosystem. Most of these micro-organisms are not harmful and the your Science Log. different species that inhabit the skin, the mouth, and the digestive tract are your constant companions. Figure 1.12 The bacterium Streptococcus mutans is a major component of dental plaque. Regular brushing is required to prevent plaque from building up and causing cavities. 18 MHR Biological Diversity  Find Out Bird Watching Alberta is home to many birds, such as the (b) Where do the birds robin, sparrow, magpie, chickadee, and duck, make their nests? which are common in neighbourhood backyards (c) What do the or parks. birds eat? Materials (d) Do other birds binoculars (optional) or animals live tape recorder (optional) in the same area notebook as the birds you pens are studying? Procedure Initiating and Planning Which ones? Communication and Teamwork Performing and Recording What Did You Find Out? Analyzing and Interpreting 1. With a group, choose two or three birds 1. How were your answers similar to or in your neighbourhood to observe. Devise different from your classmates’ answers? a procedure for making and recording 2. Based on your observations, describe the observations. niches of your study birds. Compare and 2. Make your observations of the birds, keeping contrast their niches. the following questions in mind: 3. How would your observations be different if (a) In what location do the birds live? (For you had done this activity at another time example, one bird may live next to a of year? pond in the local park.) The Broad Niche If you have had the chance to travel around northern Canada and observe the wildlife, you may have noticed two things. First, there are not as many different species of plants and animals as there are in other regions. Second, there are very large populations of the species that you do find. There are vast herds of caribou and millions of arctic hare. Even large carnivores like wolves and polar bears are found not only in northern Canada but also all around the northern regions of the globe. These same species of wolf (Canis lupus) and polar bear (Ursus maritimus) are found in Russia and northern Europe. In contrast, if you travel through the rainforests of Central and South America, you may see hundreds or thou- Figure 1.13 Wolves need sands of different species, but each population is very small. It is quite large areas of land to live. possible that you could walk through the jungle and not see the same Wolves currently travel kind of bird twice in one day. between Canada and the United States along a Why do Canadian ecosystems lack diversity but support high numbers wildlife corridor, a natural of the species that live here? The animals that live here year-round route used by animals, in must be able to withstand daily and seasonal changes in temperature. the Rocky Mountain region. Habitat and Lifestyle MHR 19  They also must be able to eat a variety of plants or other animals as seasons and conditions change. There are exceptions, but in general, organisms that survive here must have a broad niche. They must have adaptations that allow them to survive in the heat of the summer and the freezing cold of the winter. These Canadian species are generalists that are able to spread over large areas. Diversity in the Tropics: The Dangers of a Narrow Niche In the tropics, temperatures and food supplies are relatively stable. In these regions, most organisms are specialists, which means they have Figure 1.14 Like the adaptations that make them very efficient at surviving in their own envi- caribou, polar bear, and ronments. Plants and animals tend to have very narrow niches with wolf, the arctic hare is a adaptations directed toward competing for one dependable food source, generalist, and is adapted to living in cold winters and one type of soil, or one level of light. This specialization allows many mild summers. different species to inhabit a single area, but it prevents any one species from spreading over a large area. The result is that the tropics have an incredible diversity of species, but their populations tend to remain low. A specialist is well suited to one particular environment. This has been described as “the trap of specialization.” As the species competes Plants and animals that with others, the more useful adaptations it acquires and the more suc- have specialized niches in cessful it becomes. However, many of the adaptations that make a wetlands are put at risk species successful in one environment may prevent it from being able when wetlands are to inhabit other environments. For example, the lion-tailed macaque of drained. Research Alberta India is specialized for life in the forest canopy. This monkey is not suited wetlands to learn about some of the species that for life on the ground. As the forests are cut down the lion-tailed live there. You can use macaque has nowhere else to live. the library or the Internet Figure 1.15 The tropical rain forests for your research, or you of the world are areas of rich can contact an expert biological diversity. Many parts of with a wildlife conserva- these forests have never been tion group. How would explored by scientists and likely contain many undiscovered species. you advise the local government about any plans to build houses over a wetland area? Record your findings in your Science Log. www.mcgrawhill.ca/links/sciencefocus9 What happens if a new species is introduced into a food web? To begin your research for this activity, go to the web site above, and click on Web Links to find out where to go next. Present Figure 1.16 Not all specialists live in the tropics. The your findings in a short talk to your class. prairie white-fringed orchid is an endangered specialist. If populations of the hawkmoths that pollinate this flower decrease, what will happen to the orchid? 20 MHR Biological Diversity  Find Out Introducing... Generalists can live almost anywhere. Their What Did You Find Out? Analyzing and Interpreting adaptations allow them to survive in a variety 1. How have populations of local species of environments and live on a variety of differ- changed since the arrival of the introduced ent food sources. When introduced into a new species? area where there are too few predators or com- peting organisms, generalists spread rapidly. As 2. What niche does the introduced species you may recall, an introduced generalist can now occupy? sometimes take over, forcing out species that 3. Should we limit the spread of the introduced are specialized for life in local ecosystems. species? If so, what steps are being taken Procedure Performing and Recording to control the further spread of this species? Research an example of an introduced species, find out if it was introduced intentionally or 4. Make a list of all of the species introduced accidentally, and detail its effect on local species to Canada that you and your classmates and ecosystems. have researched. Enter the names of these species into a data base that other people can search. Dependencies Between Species Living things have struggled to survive for millions of years. Few, if any, have done so alone. You may think that an elk needs only water to drink and plants to eat. In fact, the elk would not be able to digest its food without the help of communities of micro-organisms that live in the elk’s rumen, a specialized stomach. In turn, the elk provides the micro-organisms with a place to live. This kind of plant cell close partnership is common in natural communities. Many plants depend on mycorrhizae, specialized fungi, mycorrhizae to help absorb water and minerals from the soil. The fungi attach to the roots of the plants, which increases the surface area of the roots. The mycorrhizae also pro- tect the plants from some diseases. The fungus benefits by being able to draw nutrients from the plants. You may recognize that this is a symbiotic relationship in which two organisms live in direct contact. It is also an example of mutualism, because the relationship benefits both species. www.mcgrawhill.ca/links/sciencefocus9 Figure 1.17 The ability of plants and mycorrhizae Many micro-organisms play important roles in the environment. to live in symbiosis is an adaptation — but with a To find out more about them, go to the web site above, and click on difference. In each case the adaptation was made Web Links to find out where to go next. Record the names of three or in close harmony with the other species. Both more beneficial micro-organisms. Write a short paragraph partners in the relationship developed compatible explaining the importance of each. adaptations at the same time. Here, the fungus is shown as it infects a plant root. Habitat and Lifestyle MHR 21  S K I L L C H E C K Initiating and Planning Performing and Recording 1-C Analyzing and Interpreting Communication and Teamwork Clover and Soil Bacteria Clover, peas, beans, and other plants called legumes have symbiotic relationships with certain soil bacteria. These bacteria, known as rhizobia, are able to live in the plant roots, where they remove nitrogen from the air and change it into nitrogen compounds the plant can use. Hypothesis Formulate a hypothesis about the importance of rhizobia to clover plants and their role in soil communities. Safety Precautions Examine the roots to find Observe the nodules on any bumps or nodules (see the highest magnification figure at top right). available. Be careful when cutting nodules from roots. Cut out one or two of the nodules and place them on a Apparatus microscope slide. Add one small shovel microscope scissors slide or two drops of methylene eye dropper cover slip blue dye. Put on a cover slip and press gently on the cov- Materials er slip to crush the nodules. methylene blue dye Procedure Clover is found in most Analyze lawns and fields. Find patches 1. Where did you find the 6. Can legume plants of clover in your schoolyard clover? grow without living or local park. in symbiosis with Dig up two or three clover 2. Could you see the bacteria rhizobia? Explain plants, taking care to keep from the crushed nodule? your answer. the roots intact. 3. Why is it difficult to see the bacteria? Extend Your Knowledge Conclude and Apply 4. What evidence did you 7. Repeat the experiment observe in the field that with pea plants or indicates the bacteria are bean plants. Choose adding nitrogen to the soil? plants from fertilized and unfertilized soils. 5. Why do farmers some- Which plants have In the lab, gently rinse the times alternate clover nodules? Explain roots to remove any soil. with other crops? your findings. 22 MHR Biological Diversity  Without special stains, many microscopic structures would be almost impossible to see, even using a microscope. As mycorrhizal fungi surround and enter roots, the roots themselves change shape. Shown here are the roots of an orchid seedling colonized by a mycorrhizal fungus. In order to see mycorrhizae, biologists used a fluorescent stain. A blue light was then shone on the stained specimen. When seen through a microscope, the mycorrhizal fungi showed up in fluorescent colours. Life in the Extreme Would you expect to find life at 110 °C? In a salt lake? In the desert sand? In fact, there are organisms adapted to living in all of these extreme environments. The Antarctic springtail, for example, is adapt- ed to the extreme cold. This tiny arthropod produces a type of antifreeze in its tissues, which allows it to survive temperatures as low Specialized bacteria as -35 °C. Snow algae, which can be found on snowfields around the called archaebacteria globe, have cell membranes that are adapted to cold temperatures. make their home in the boiling waters of geysers Being photosynthetic, the snow algae make their food using the energy in Yellowstone National of sunlight. However, high in the mountains, sunlight can be very Park, in the United States. intense. Some snow algae produce reddish pigments that protect The study of heat-loving against the Sun’s damaging rays. bacteria led to the discovery of an important Many organisms have adaptations that defy our current understanding heat-stable product used of life. Scientists who are curious about the possibility of life on other, in scientific research. less hospitable planets hope to learn from these strange, earthly species. Figure 1.18 Have you ever seen pink snow? Snow alga is a red alga that is well adapted to living in cold climates. It can be found living on the surfaces of snowfields and glaciers. Figure 1.19 The desert spadefoot frog has its niche in the harsh conditions of the Australian desert. This frog can remain inactive for years while buried in the desert sand awaiting rain. Habitat and Lifestyle MHR 23  Across Canada Lemmings do not intentionally jump off cliffs to drown in the One great thing about sea, as some people may think. Mass movements of these working in the North, near-sighted little rodents may result in their accidental Deborah reports, “was drowning, however. University of British Columbia ecologist getting to know the Dr. Deborah Wilson went to Nunavut in Canada’s Far North Inuit who lived near our to study lemmings. As part of her study, she looked at their remote field station. population peaks and crashes, which have led to the cliff- Some helped with our jumping myth. field study, and we were “Lemming numbers fluctuate quite regularly,” Deborah able to learn about their explains, “with peaks in the population every three years. We culture and the difficulties place small radio transmitters on individual lemmings and they face living in an follow their movements. This helps us learn whether they arctic environment.” become food for predators or whether some other factor is Deborah started her working life as a computer programmer, responsible for the steep declines in numbers. Predators (such but later realized that she would rather be an ecologist. This as arctic foxes and ermine) are responsible for most lemming meant more years of study, but it was worthwhile. “Keep deaths, but that’s not the whole story. Lemmings reproduce at striving to do what you love,” she advises students. “It took a lower rate when they are very abundant. Whether their lower me a long time to be able to work in the field of ecology, reproduction is a response to the population density or to a where my real interest lies. It is much less lucrative than shortage of food or space to live in is not known.” working in business, but that doesn’t matter to me at all.” TOPIC 2 Review 1. What two things make up an organism’s niche? 2. (a) Both red squirrels and grey squirrels live in Alberta, although the grey squirrel was introduced from eastern Canada. Both feed on seeds, nuts, flowers, fruit, insects, and birds’ eggs. Do these squirrels have to compete for resources? What are some ways they could avoid compet- ing for resources? (b) Would you classify red squirrels and grey squirrels as specialists or generalists? Explain. 3. Describe two examples of symbiotic relationships found in nature. In each example, how do the adaptations of one organism depend on the other’s? No one knows for sure how they got there, but the bright green parrots of New York City aren’t leaving anytime soon. Flocks of the birds make New York their home, where they build nests on high-voltage power poles. The parrots are also called feral parakeets because they are probably descended from pet birds that escaped. It is hard to say if these parrots are generalists or just very lucky specialists! 24 MHR Biological Diversity  Wrap-up TOPICS 1–2 If you need to check an item, Topic numbers are provided in brackets below. Key Terms variation structural adaptation competition narrow niche biological diversity behavioural adaptation broad niche specialization species diversity index generalist symbiotic association speciation environment specialist Reviewing Key Terms Understanding Key Concepts 1. In your notebook, match the description in 2. Examine the photograph of the eagle. What column A with the correct term in column B. structural and behavioural adaptations does it have that enable it to obtain food? A B a struggle for resources diversity index (1) 3. How could you go about measuring the between organisms of the biological diversity in a tropical area? What same or different species would you expect to find? (1) What has a species with a very generalists (2) happened over time to produce this level narrow niche of diversity? (2) the word that describes behavioural adaptations (1) 4. What are the advantages of a broad niche? both the role and the habitat When can these advantages turn out to be of an organism disadvantages for different species? (2) the many differences competition (2) between individuals of the 5. Define the term “species” using your own same or different species words. Are all organisms that look alike the a mathematical expression symbiotic (2) same species? Are all organisms that look of the different kinds of different from separate species? Explain organisms in an area your answer. (1) a direct or close association variation (1) 6. If an area of tropical rainforest were cleared between two different species to make room for a farm, how might the local the habits of a species that niche (2) wildlife be affected? Would the consequences have been developed over time be worse for specialists or generalists? populations of these specialist (2) Explain. (2) organisms tend to be high, although there is not usually very much diversity in the kinds of these organisms Wrap-up Topics 1–2 MHR 25