General Biology I Lecture 5 PDF

# BAZE UNIVERSITY ABUJA ## DEPARTMENT OF BIOLOGICAL SCIENCES ### General Biology I ### BIO 101 ### LECTURE 05 By MRS FATIMA MAIRAMI ## ELEMENTS OF ECOLOGY AND TYPES OF HABITAT ### CONTENTS * 5.0 - Introduction * 5.1 - Scope of ecology * 5.2 - Density and Distribution of population * 5.3 - Habit...

# BAZE UNIVERSITY ABUJA ## DEPARTMENT OF BIOLOGICAL SCIENCES ### General Biology I ### BIO 101 ### LECTURE 05 By MRS FATIMA MAIRAMI ## ELEMENTS OF ECOLOGY AND TYPES OF HABITAT ### CONTENTS * 5.0 - Introduction * 5.1 - Scope of ecology * 5.2 - Density and Distribution of population * 5.3 - Habitat and Ecological niche * 5.4 - The nature of ecosystem ## 5.5 - Introduction Ecology is the study of the interactions of living things with their environment. Ecologists ask questions across four levels of biological organization - organismal, population, community, and ecosystem. At the organismal level, ecologists study individual organisms and how they interact with their environments. At the population and community levels, ecologists explore, respectively, how a population of organisms changes over time and the ways in which that population interacts with other species in the community. Ecologists studying an ecosystem examine the living species (the biotic components) of the ecosystem as well as the nonliving portions (the abiotic components), such as air, water, and soil, of the environment. The environment or ecosystem is an area where all the biotic and abiotic components interact. ## 5.1 - Scope of ecology Taylor (1936), in an attempt to define ecology, has very rightly pointed out that scope of ecology by stating that ecology is the science of all the relations of ecosystems, all organisms to all their environments. Since ecology is the study of the interaction of the organisms with other organisms and the physical environment. Ecology like many biological discipline, is wide ranging. At one of its lowest levels, ecologist study how the individual organism is adapted to its environment. For example, they study why fishes in a coral reef live only in warm tropical water and how the fishes feed within that habitat. ## 5.2 - Density and Distribution of population Population density is the number of individual per unit area or volume while population distribution is the pattern of dispersal of individual within the area of interest that is where people live. Population density is the number of people living in a particular area usually 1 square kilometre and can be written as total population/land area. The world's population is spread unevenly across the globe with concentrations of large numbers of people living in the same area. The world as a whole has more 'empty' areas than 'crowded' areas. There are several physical and human factors to explain this. ### Distribution of World Population in 2005 A pie chart is shown with different colored sections: * Middle East * South America * Other North America (incl. Caribbean) * USA * Europe * Africa * Oceania * People's Republic of China * Other Asia * India * Indonesia **Fig1-Distribution of world population in 2005** ## 5.3 - Habitat and Ecological niche Each species occupies a particular position in the community both in spatial sense( where it lives) and in a functional sense( what role it plays).An organism lives and reproduces in its habitat. The habitat of an organism might be forest floor, a swift stream,or the ocean edge. The ecological niche of an organism is the role it plays in its community, including its habitat and its interaction with other organisms. The niche includes the resources an organism uses to meet its energy, nutrition and survival demands. The organism niche is affected both by abiotic factor (such as climates and habitat) and the biotic factors( such as competitors, parasites and predators present in the habitat) ### NICHE EXAMPLE: **BARKING TREE FROG** **NICHE** * **Habitat:** wooded regions, wetlands * **Behaviors:** often found in trees, can burrow, barking call attracts mates * **Feed on:** small insects * **Eaten by:** birds, snakes, raccoons * **Impact on ecosystem:** limit insects, aerate soil, serve as food source ## Different between Habitat and Niche 1. Habitat is a specific place or locality where a community resides while Niche is an ecological component of habitat which is delimited by functioning of an organism. 2. A habitat has a number of niches. While A niche does not have components. 3. Habitat supports a number of species. While Niche supports a single species. 4. In a habitat a species does not change its habitat. While a species may live in more than one niche in different stages of its life cycle. ## Habitat vs Niche * **Habitat** * The habitat is the place where an organism lives out its life. * It is where the organism finds food, shelter and mates * **Niche** * A niche is its role in the community and how it interacts with the environment. * How it obtains food, mates and protection from predators. A diagram is shown of a spruce tree with 3 different types of warblers in different areas of the tree, labeled as: * Bay-Breasted Warbler -Feeds in the middle part off the tree * Cape May Warbler - Feeds at the tips of branches near the top of the tree * Yellow-Rumped Warbler - Feeds in the lower part of the tree and at the bases of the middle branches **Fig 2-Ecological Niche** ## Abiotic Factors Abiotic factors of the environment determine the habitat (the particular environment an organism lives) of an organism; such factors include: sunlight, temperature, air, water and soil, which are grouped into: * **Climatic factors** - temperature, water, light and gases * **Edaphic factors** – soil types, pH and humus content * **Physiological factors** - aspect (position of the area in relation to the sunlight), slope and altitude. ## Biomes of the earth The term biome refers to a large geographical region that has a particular type of climax community, determined by the climate and other physical conditions. There are two major biomes: terrestrial and aquatic. ### Terrestrial biomes include: * **Tropical Rain Forest** - geographically located in parts of South & Central America, Southeast Asia, parts of Africa, southern India, & northeastern Australia - home to more species than all other land biomes combined; - characterized by: hot & wet year-round; thin, nutrient-poor soils. - **Dominant plants:** include broad-leaved evergreen trees; ferns; vines. - **Dominant wildlife:** sloths, jaguars; monkeys; parrots, butterflies, ants. * **Taiga (Boreal) Forest** - world largest biome. - geographically located in North America, Asia & northern Europe; - a dense evergreen forests of coniferous trees; - characterized by: long, cold winters; short, mild summers; moderate precipitation; high humidity; acidic, nutrient-poor soils. - **Dominant plants:** spruce, fir, berry-bearing shrubs, etc. - **Dominant wildlife:** timber-wolves, moose, beavers, etc. * **Tropical Savanna** - geographically located in large parts of eastern Africa, southern Brazil, northern Australia; - are characterized by a cover of grasses; - warm temperatures; - seasonal rainfall; - compact soil; - frequent fires set by lightning. - **Dominant plants:** tall, perennial grasses; trees or shrubs. - **Dominant wildlife:** lions, elephants, giraffes, zebras; eagles, termites. * **Desert** - geographically located in Africa, Asia, the Middle East, North & South America, and Australia; - characterized by: low precipitation; variable temperatures; soils rich in minerals but poor in organic material. - **Dominant plants:** cacti, creosote bush. - **Dominant wildlife:** mountain lions, mule deer, kangaroo, rats; owls, butterflies, flies, tortoises, rattlesnakes, and lizards. * **Temperate Grassland** - geographically located in central Asia, North America, Australia, central Europe, & parts of South America; - characterized by warm to hot summers; cold winters; moderate, seasonal precipitation; fertile soils; occasional fires. - **Dominant plants:** lush, perennial grasses and herbs; most are resistant to drought, fire, and cold. - **Dominant wildlife:** coyotes, grizzly bears, antelope, rabbits, hawks, snakes, grasshoppers. ### Aquatic biomes Aquatic biomes: can be broken down into two basic regions, freshwater (ponds and rivers) and marine (oceans and estuaries). * **Freshwater regions** - Freshwater is defined as having a low salt concentration - usually less than 1%. - Plants and animals in freshwater regions are adjusted to the low salt content and would not be able to survive in areas of high salt concentration (i.e., ocean). - There are different types of freshwater regions: ponds and lakes, streams and rivers, and wetlands. * **Marine regions** - cover about three-fourths of the Earth's surface and include oceans, coral reefs, and estuaries. - Marine algae supply much of the world's oxygen supply and take in a huge amount of atmospheric carbon dioxide. - The evaporation of the seawater provides rainwater for the land. ## 5.4 - The nature of ecosystem Our planet is unique in many ways. Unlike the other planets n our solar system, the earth has water, an atmosphere, and abundant life. Perhaps our planet should be called water instead of the earth. Water is present in the hydrosphere which covers over three quarter of the earth surface. The ocean moderates the tempreature of the earth as the surface temperature rise, the ocean takes up a great deal of heat and then as the temperature cool, they return heat slowly to the atmosphere. This helps keep the temperature on earth suitable to life. * **Atmosphere** -The atmosphere is concentrated in the lowest 10 kilometers near earth but extends out at least 1000 kilometer. - Among other gases, the atmosphere contained carbon dioxide, nitrogen,and oxygen that are both used and released by living things. - Carbon dioxide is necessary for photosynthesis and oxygen is necessary for cellular respiration and in the upper atmosphere it becomes the ozone that is a substance that shield the earth from ultraviolet radition and makes life possible on land. * **Lithosphere** - is a rocky substratum that extends from the earth's surface to about 100 kilometers deep. - The weathering of the rocks supplies mineral to plants, Besides minerals soil contains decaying organic materials known as humus. The decomposers play a vital role in breaking down organic matter returning inorganic nutrients to plants so that photosynthesis can continue. * **Biosphere** is that part of the atmosphere, hydrosphere and the lithosphere that contains living things. This layer ranges from heights of up to ten kilometres above sea level, used by some birds in flight, to depths of the ocean such as the Puerto Rico trench, at more than 8 kilometres deep. These are the extremes; however, in general the layer of the Earth containing life is thin: the upper atmosphere has little oxygen and very low temperatures, while ocean depths greater than 1000 m are dark and cold. In fact, it has been said that the biosphere is like the peel in relation to the size of an apple. A diagram shows the 4 "spheres": Lithosphere (crust and mantle), Hydrosphere (water), Biosphere (zone of life), and Atmosphere (air). **Fig 4-The ecosystem** ## Practice Question 1. Define the following terms * **Habtitat** * **Niche** 2. List and explain the difference between habitat and niche. 3. List out the Abiotic factors in the environment.