Ch 3 - The Biosphere 3.1 What is Ecology?
Ecology The study of the interactions between organisms, and between organisms and their environment
Levels of Organization of Living Things Organisms individual living thing Species Group of similar organisms that can successfully reproduce Population Group of organisms of the same species living in one area
Community The group of multiple populations of different species living in one area Ecosystem The community of organisms and the environment they live in Environment - Describes the conditions (factors) surrounding an organism
Biome Group of ecosystems that share similar climates and organisms Biosphere All life on Earth and the part of Earth in which they live (all biomes)
Parts of the Environment Many factors in the environment affect how an organism lives: Abiotic factors Parts of the environment that are not alive, and were never alive (non-living) Includes physical aspects, such as: temperature, water, sunlight, soil, etc
Biotic factors Parts of the environment that are, or once were, alive Includes: organism, dead plant material, etc. Abiotic and Biotic factors are closely associated and depend on each other
3.2 Energy, Producers, and Consumers
Energy in an Ecosystem All organisms require energy to live (for movement, reproduction, growth, etc) The primary source of energy on Earth is the sun
Primary producers Organisms that first produce energy-rich compounds used by other organisms for energy, captured directly from the sun or chemicals, and convert it to a usable form Also called Autotrophs (make their own food)
Processes used: Photosynthesis capturing energy from the sun (used by plants, algae) Chemosynthesis capturing energy from inorganic compounds (used by some bacteria)
Consumers Organisms that capture energy by eating other organisms Also called Heterotrophs
Types of consumers Herbivores only eat plants Ex: Omnivores eat plants and animals Ex: Carnivores eat only other animals Ex:
Scavengers eat dead animals Ex: Decomposers chemically break down organic matter, causing decay Ex: Detritivores eat decayed organic matter, called detritus Ex:
Type Definition Example Herbivore Cows, rabbits Heterotroph that eats animals Omnivore Humans, bears, pigs Detritivore Decomposer Heterotroph that consumes dead animals but doesn t typically kill them itself
3.3 - Energy Flow in Ecosystems
Food Chains and Webs Food Chains a single series of steps in which organisms transfer energy by eating and being eaten Must include a primary producer and consumers (one or more) First consumer in chain is called primary consumer (1st), second is secondary consumer (2nd), Tertiary consumer (3rd), etc.
Arrows show where energy is going (points toward consumer) Example - Grass Antelope Lion
Energy transfer in the food chain
Food Web interconnected network of feeding relationships, showing multiple relationships between producers and consumers Several individual food chains are found within a food web
Decomposers and detritivores are necessary for recycling some energy within the food web Example see figure 3-9, pg 75
A food web
Disturbance of food webs Because feeding relationships in an ecosystem are interconnected, if one part is disturbed, the entire web can unravel Decline/increase in population size, a species becomes extinct, leaves the area, etc.
Trophic Levels Each step within a food chain is called a trophic level First trophic level is always primary producers All following steps are always a consumer
As energy moves up each trophic level, energy is lost Organism in each level used the energy it captured for its own use Consumers only receive 10% of energy from previous trophic level
Pyramid of energy:
Number of trophic levels is usually limited to 4-5, because of energy loss Because energy decreases as trophic level increases, the number of organism at each level also decreases (less energy available) Primary producers are plentiful, less primary consumers, even less secondary consumers, and very few tertiary consumers
Feeding relationships
3.4 Cycles of Matter
Nutrients and other materials move through the biosphere in cycles The water cycle movement between land, air, and organisms Nutrient cycles movement between organisms and environment Carbon cycle, nitrogen cycle, Phosphorus cycle
Water Cycle
The water cycle
The water cycle
Carbon Cycle
What is the carbon cycle?
Labeling the carbon cycle
Nitrogen Cycle
What is the nitrogen cycle?
Labelling the nitrogen cycle
Components of the nitrogen cycle
Phosphorus Cycle
Ecological terms
Create a Food Web Below are a list of Antarctic animals and a description of what they eat. Using this information, construct a food web that shows their interactions and how energy is passed along in this ecosystem. Diatoms microscopic marine plants; get their energy from the sun; they don t eat anything Krill 1-4 inch shrimp-like animals; they graze on diatoms Blue whale one of the largest whales; feeds on krill Crabeater Seal feeds on krill Winged birds various species; feed on krill Adele penguins feeds on krill Skua small scavenging bird; feeds primarily on the dead carcasses of Adele penguins Small fish and squid feed on krill Emperor Penguin feed on small fish and squid Large Fish Feed on small fish and squid Weddell Seal feed on small fish and squid Ross Seal Feed on small fish and squid Leopard Seal Feeds on Ross Seals, Weddell seals, Emperor penguins, Adele penguins and Crabeater seals Killer Whale Feeds on Leopard Seals, Crabeater Seals, and blue Whales