Chapter 3 Ecology

 Ecology – the scientific study of interactions among organisms and between organisms and their environment.  The term ecology was coined in 1866 by Ernst Haeckel  oikos is greek for house

 Biosphere – combined portions of the planet in which all life exists  The biosphere is from 8 km above the surface to 11 km below sea level.

Levels of Organization  Species – a group of organisms so similar to each other that they can breed and produce fertile offspring.  Populations – groups of individuals that belong to the same species and live in the same area.

Species of Sea Turtles Green Hawksbill Kemp Ridley Leatherback Loggerhead Olive Ridley Website Flatback

Levels of Organization  Community – a group of different species that live in the same area.  Ecosystem – a collection of all of the organisms that live in a particular place together with the nonliving aspects of the environment.

Pelagic Waters (community)  The open ocean  The pre-juveniles feed on zooplankton  And Nekton CopepodJellyfish Krill Oysters (intertidal zones and bays Scallops Subtidal Zones bays

Biome  A biome is a group of ecosystems that have the same climate and dominant communities.  The biosphere is the highest level of organization.

Ecological Methods  Binoculars, magnifying glasses, microscopes, DNA, field cameras  Modern research uses three approaches;  observing, experimenting, and modeling

 Observing – first step  Experimenting – to test a hypothesis….field or lab  Modeling – used to gain insight into complex phenomena (weather)

Energy Flow  The flow of energy through an ecosystem is one of the most important factors that determines the system’s capacity to sustain life.  Sunlight is the main energy source for life on Earth. Less than 3% of the energy from the sun that strikes the Earth is used.

 Some types of organisms rely on the energy stored in inorganic chemical compounds.  hot springs and undersea vents

 Only plants, some algae, and certain bacteria can capture energy from sunlight or chemicals and use that energy to produce food.  Autotrophs – assemble organic molecules from inorganic molecules

 Autotrophs are also called producers because they make their own food.  The best known autotrophs are those that harness solar energy through photosynthesis.

 During photosynthesis, light energy is used to power chemical reactions that convert carbon dioxide and water into oxygen and carbohydrates.  carbohydrates are sugars or starches

 This process provides us with oxygen and removes carbon dioxide in the atmosphere.  6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2

 Plants - land  Algae - mostly oceans  Bacteria - tidal flats and salt marshes (cyanobacteria are the most common)

Cyanobacteria

Chemosynthesis when organisms use chemical energy to produce carbohydrates. when organisms use chemical energy to produce carbohydrates.  they produce food in the absence of light  they rely on energy in the chemical bonds of inorganic molecules like hydrogen sulfide (H 2 S)  mostly bacteria  found in hot springs like yellowstone and hydrothermal ocean vents

Heterotrophs  Organisms that rely on other organisms for their energy and food supply.  Also called consumers

Types of Heterotrophs  herbivores – obtain energy from plants  carnivores – eat animals  omnivores – eat plants and animals  detritivores – feed on plant and animal remains ….or dead matter  decomposers – break down organic matter

Feeding Relationships  Energy flows in an ecosystem in one direction, from the sun or inorganic compounds to autotrophs and then to various heterotrophs.

Food Chains  The energy stored by producers is passed from organism to organism in a series of steps called a food chain.  Grass - Antelope - Coyote  Algae - Zooplankton - Small fish - Squid - Shark

Food Webs  When the feeding relationships in an ecosystem form a network of complex interactions it is called a food web.  Each step in a food chain or web is called a trophic level.

Ecological Pyramids  A diagram that shows the relative amounts of energy or matter contained within each trophic level of a food chain or web.  There are three different types of ecological pyramids;  Energy Pyramids, Biomass Pyramids, and Pyramids of Numbers

Energy Pyramids  There is no limit to the number of trophic levels that a food chain can support.  Only part of the energy that is stored in one trophic level is passed to the next. This is because organisms use much of the energy that they consume on life processes such as respiration, movement, and reproduction.

 Only about 10% of the energy at one trophic level is transformed to organisms at the next trophic level.

Biomass Pyramid  The total amount of living tissues within a given trophic level.  Biomass is usually expressed in terms of grams of organic matter per unit area.  Represents the amount of potential food available for each trophic level in an ecosystem.

Pyramid of Numbers  Based on numbers of organisms at each trophic level.

Cycles of Matter  95% of most organisms are made of C, H, N, and O  Unlike the one way flow of energy, matter is recycled within and between ecosystems.  Matter is passed from one organism to another through biogeochemical cycles.  Matter is not used up, it is transformed.

The Water Cycle  Water cycles through our environment in various ways.  The process by which water changes from liquid form to an atmospheric gas is called evaporation.  Transpiration – evaporation from the leaves of plants.  Precipitation – rain, snow, sleet, hail

The Carbon Cycle