Chapter 40 Bio
the study of populations in relation to their environment including environmental influence on population density and distribution, age structure, and variations in population size (Population ecology or autoecology is a sub-field of ecology that deals with the dynamics of species populations and how these populations interact with the environment. It is the study of how the population sizes of species groups change over time and space.)
Because Earth is titled on its axis relative to its plane of orbit around the sun the intensity of solar radiation varies seasonally. The intense solar radiation near the equator initiates a global pattern of air circulation and precipitation.
A rain shadow is a patch of land that has been forced to become a desert because mountain ranges blocked all plant-growing, rainy weather. On one side of the mountain, wet weather systems drop rain and snow. On the other side of the mountain—the rain shadow side—all that precipitation is blocked.
(Biomes are large areas on Earth with similar conditions, such as climates and living organisms)
So the reason we can say that hiking from Gatlinburg, Tennessee, at 393 meters of elevation in the Smoky Mountains region, to the top of Mount LeConte, at 2,010 meters, is like traveling to Canada is because we are increasing in elevation and we are increasing in latitude from the equator so it is getting colder just like it is in Canada.
2. hurricans and other storms create opening for new species in many tropical and temperate forsts.
2. Temperature is usally high averaging: 25-29 C.
3. Location/ Distribution: equalatorial and subequatorial regions.
4. Flora broadleaf evergreen tees are dominant in rain forests (while dry forest trees drop their leaves during the dry season)
5. Fauna: home to million of animal species (including 5-30 million still undescribed species of insects, spiders, and other arthropods). Animal diversity is higher than in any other terrestrial biome. The animals are adapted to the vertically layered environment and are often inconspicuous
2. temperature: varies seasonally and daily, it may exceed 50 C in hot deserts and fall below -30 C in cold deserts
3. Location/distribution: deserts occur in bands near 30 north and south latititude or at other latitudes in the interior of continents (for example the Gobi deser of north central asia)
4. Flora: dominated by low widely scattered vegetations; common plants include succulents such as cacti or euphorbs, deeply rooted shrubs, and herbs that grow during infrequent moist periods.
a. Desert plant adaptations include tolerance to heat and desiccation, water storage, reduced leaf surface area, and physical defenses such as spines and toxins in leaves.
b. Most desert plants carry out C4 or CAM photosynthesis
5. Fauna: scorpions, ants, beetles, snakes, lizards, migratory nd resident birds, and seed eating rodents
a. Many species in hot deserts are active at night when the air is cooler
b. Water conservation is a common adaptation and some animals can obtain all their water by breaking down carbohydrates in seeds
2. Temperature: averages 24-29 C but varies seasonally more than in tropical forests
3. Location/Distribution: equatorial and subequatorial regions
4. Flora: scattered trees oftern are throny and have small leaves (an apparent adaptation to the releativly dry condition), firs are common in the dry season and the dominat plant species are fire adapted and tolerant of seasonal drought, grasses and small nonwoody plants called forbs make up most of the ground cover
5. Fauna: large plant eating mammals such as; wildebeests and zebras, and predators including lions and hyenes. Domminet herbivores are insects especially terminates.
2. Temperature: Fall winter and spring are cool with average temps of 10-12 C and average summer temperature is 30 C
3. Location/Distribution: midlatitude coastal regions on several continents
4. Flora: dominated by shrubs and smll trees adapted to frequent fires; some fires adapted shrubs produce seeds that will germinate only after a hot fire, food reserves stored in their roots enable them to resporut quickly and use nutrients released by the fire
a. Adaptations to drought include tough evergreen leaves which reduce water loss
5. Fauna: browsers such as deer and goats (that feed on twigs and buds of woody vegetations), also many insects, amphibians, small mammals, and birds
2. Temperature: below -10 C in winter and reach 30 C in summer
3. Location/ Distribution: typically at midlatitudes often in the interior of continents
4. Flora: dominant plants are grasses and forbs (which vary in height from a few centimets to 2m in tall grass prairie), many graslnand plants have adaptations that help them survive periodic protracted droughts anf fire
5. Fauna: large mammals such as bison and wild horses (they help prevent establishment of woody shrubs and trees), burrowing ammals such as prairie dogs
2. Temperature: winters are cold, in siberia typically ranges from -50 C in winter to over 20 C in summer
3. Location/Distribution: in a broad band across northern north America and Eurasia to the edge of the artic tundra, is the largest terrestrial biome
4. Flora: Cone bearing trees (conifers): such as pine, spruce, fir, and helock (some species depend on fire to regenerate). The conical shape of many conifers prevents snow from accumulating and breaking their branches and their needle like or scale like leaves reduce water loss.
a. Plant diversity in the shrub and herb layers is lower than in temperate broadleaf forests
5. Fauna: migratory birds nest in northern coniferous forests, mammals including moose, brown bears, and Siberian tigers, periodic outbreak of insects (can kill vast tracts of trees).
2. Temperature: winter temperature averages around 0 C summers are humid with maximum near 35 C
3. Location/ Distribution: Midlatitiudes in the Nothern Hempishpere with smaller areas in Chile, South Africa, Australia, and New Zealand
4. Flora: dominant plant is deciduous trees (which drop their leaves before winter when low temperatures would reduce photosynthesis). In australia evergreen eucalyptus trees are common
5. Fauna: Nothern hempespere many mammals hibernate in winter while bird species migrate to ears with warmer climates
2. Temperature: Winters are cold with average temperatures in some area below -30 C summer temperatures generally average less than 10 C
3. Location/ Distribution: covers expansive ares of the artic (amounting to 20% if the earth;s land surface). High winds and low temperatures produce alpine tundra on very high mountaintops at all latitiudes including the tropics
4. Flora: herbaceous; typically a mix of mosses, graases, and forbs, with some dwarf shrubs, trees, and lichens,
a. Permintaly frozen soil layer called permafrost restricts the growth of plant roots
5. Fauna: large grazing musk oxen are resident while caribou and reindeer are migratory, Preditors inckude bears, wolves, foxes, and snowy owls. Many bird species migrqate to the tundra for summer nesting
(Dispersion plays a role in the global distribution of organisms), It can be a key factor limiting the distribution of a species (like kangaroos could live anywhere else but cant go anywhere because they are land animals thus dispersion limits them)
– is the most common pattern of dispersion
– clumping is because the conditions is good there (like good resources, lots of food, good conditions)
– also clumping of animals may also be associated with mating behavior
– forming groups may also increase the effectiveness of predation or defense
– Rarer than clumped patterns
– Uniform is because of Competition (society)
– Also uniform occurs in antagonistic social interaction such as territoriality (the defense of a bounded physical space against encroachment by other individuals
– Random occurs in the absence of strong attraction or repulsion among individuals or where key physical or chemical factors are relatively constant across the study area
eventually in a J-shaped growth curve when population size is plotted over time)
(Elephants in south Africa grew exponentially because they were protected from hunting.
Another example is when a species has unlimited amount of food supply and resources.
One example is when a species has no predators/ are a protected species.
Another example is when a species)
A metapopulation is a group of populations linked by immigration and emigration