Transcript Ecology
Ecology Ecology • Ecology = the study of the interactions among organisms and their environment Abiotic Factors The nonliving or physical things in an environment are called ABIOTIC factors. - - Examples: Sunlight Temperature Rainfall Air Soil Earthquakes Biotic Factors The living or biological things in an environment are called the biotic factors. Examples: • parasitism • disease • predators • prey • competition Levels of Organization • Ecologists study organisms ranging from the various levels of organization: – Species – Population – Community – Ecosystem – Biome – Biosphere Levels of Organization Species =a group of similar organisms that can breed and produce fertile offspring Levels of Organization Population =group of organisms, all of the same species, which interbreed and live in the same area. EX: all the turtles in Town Lake Levels of Organization Community = a collection of different populations that live together Levels of Organization Ecosystem = a collection of interacting populations and their physical surroundings (abiotic factors) Levels of Organization Biome = a group of ecosystems with the same climate and dominant communities Tropical rain forest Temperate grassland Temperate forest Tundra Tropical dry forest Desert Mountains and ice caps Tropical savanna Temperate woodland and shrubland Northwestern coniferous forest Boreal forest (Taiga) Levels of Organization Biosphere= the part of the earth where life exists including land, water, air, and atmosphere • It extends from high in the atmosphere to the bottom of the oceans. • If the earth could be shrunk to the size of an apple, the biosphere would be no thicker than the apple's skin. Habitat vs. Niche HABITAT • Place where an organism lives • Lots of organisms have the same habitat NICHE • Role and position a species has in its environment • Organisms want a unique niche Habitat vs. Niche HABITAT • Ex: red fox’s habitat is the forests’ edge, meadows, and river bank NICHE • Ex: red fox’s niche is a predator which feeds on the small mammals etc. that is active at night Symbiotic Relationships Symbiosis = permanent (living together) relationship between two different organisms 3 types: 1. Mutualism 2. Commensalism 3. Parasitism Symbiotic Relationships 1. Mutualism = when both organisms benefit from each other EX: clownfish and sea anemone EX: lichen EX: flower and bee Symbiotic Relationships 2. Commensalism = one organism benefits, the other is not helped or harmed EX: pilot fish and shark (fish eats scraps from the shark’s food) Symbiotic Relationships 3. Parasitism = one organism benefits, the other is harmed EX: tapeworms EX: ticks Predation Relationships • Predator = an animal • that feeds on another animal Prey = that animal that is killed and eaten EX: lion (predator) hunts and eats the zebra (prey) Population Size • Size of a population • • changes over time. Most populations stabilize rather than grow endlessly. Why? Because of demands on the ecosystem (ex. Enough food?) Limiting Factors • Limiting Factors = any environmental factors that limit the size of a population EX: - Availability of food - Availability of water - Availability of oxygen - Availability of sunlight Density- Dependent Limiting Factors • Limit the growth of a • population when the pop gets to a certain size Population density = the # of organisms in a given area Density- Dependent Limiting Factors Two Main Factors 1. Competition- when a pop gets big, organisms compete for available resources EX: group of trees fighting for sunlight, soil, or water Density- Dependent Limiting Factors 2. Predation – if the predator population becomes too large, there will not be enough prey to support it Density-Independent Factors • Limit the growth of a population regardless of its size EX: - Climatic events like extreme cold/heat, tidal waves, volcanoes, flooding, drought Density-Independent Factors • Diseases such as HIV, influenza, tuberculosis, Bubonic Plague, and etc. • They kill humans without the care of the population. Carrying Capacity • Carrying capacity = • the largest population that a given environment can support over a long period of time Important for conservationists in managing wildlife pops Carbon Cycle • The cycling of carbon dioxide from the atmosphere through the land and back. • Processes of photosynthesis and aerobic respiration had this cycle balanced. • Industrial revolution brought about the burning of fossil fuels which increased the amount of CO2 released into the atmosphere. • This excess of CO2 (greenhouse gas) has increased the Earth’s atmospheric temperatures resulting in a climate change. Water cycle • The cycling of water • from the atmosphere down to Earth and back to the atmosphere. This cycle is driven by solar energy. Nitrogen Cycle • The cycling of nitrogen from the Earth to the atmosphere and back. • Nitrogen cycle was in balance but the addition of fertilizers along with burning of fossil fuels has unbalanced the cycle. • Excess of nitrogen in our water systems results in eutrophication. • Eutrophication is also known as alga blooms. It ends up killing off all the organisms in the system. Oxygen Cycle • The cycling of oxygen from the atmosphere through photosynthesis and aerobic respiration. QUESTIONS 1. Which of the following is a symbiotic relationship where both organisms benefit? a. mutualism b. commensalism c. altruism d. competition Questions 2. Which of the following pairs of animals are most likely to have a predator-prey relationship? a. dog and tapeworm b. buffalo and tickbird c. spider and fly d. whale and barnacle Questions 3. Some species of shark allow small fish to enter their mouths without eating them. Inside the mouth, the small fish feed on debris around the teeth. The sharks get their teeth cleaned, which reduces the risk of decay and infection. Which term best categorizes this relationship? a. predation b. mutualism c. commensalism d. parasitism Questions 4. Which of the following is a densitydependent limitation on population growth? a. wildfire b. competition c. unlimited nutrients d. severe drought Questions 5. Which cycle is responsible for the increase in the Earth’s atmospheric temperatures? a. Water b. Nitrogen c. Carbon d. Oxygen