Ecology The study of interactions that take place between organisms and their environment.

Organisms and Their Environments Species interact with both other species and their nonliving environment. Interdependence theme in ecology—one change can affect all species in an ecosystem.

Levels of Organization

Biosphere Part of the Earth that supports living things From high in the atmosphere To the bottom of oceans

Abiotic Factors Non-living parts of an organisms environment Air currents Temperature Moisture Light soil

Biotic Factors All the living organisms that inhabit an environment Animals Plants Fungi Protists—weird group including algae and amoebas Bacteria

Organization Ecosystem (made of biological communities and abiotic factors) Biological Community (made of populations) Populations (made of organism of the same species)

Ecosystem Terrestrial: Located on land Aquatic: Forest, Meadow, and rotting log Aquatic: Fresh water: ponds, lakes, and streams Marine (salt water): 70% of Earth’s surface

Biological Community Contains many populations (species) Interact with one another Changes in one can cause changes in the others

Population Same species Interbreed Live in the same area At the same time Members still compete with one another

Organisms in a Changing Environment Acclimation Some organisms can adjust their tolerance to abiotic factors Control of Internal Conditions Conformers: organisms that do not regulate their internal conditions; they change as their external environment changes. Regulators use energy to control some of their internal conditions.

Who is a conformer? Regulator?

Escape from Unsuitable Conditions Some species survive unfavorable environmental conditions by becoming dormant or by migrating

Habitat Where an organism lives out its life Lawn, forest, pond, can you think of any? Can change because of natural and human causes Many species can share a habitat

Niche Strategies and adaptations a species uses in its environment Meets specific needs for food and shelter All interactions with biotic and abiotic No two have exact same niche Adaptations

Generalists vs. Specialists relatively tightly defined niches and have a narrow range of tolerance better off when their preferred environment remains stable have broad niches and tolerate larger changes in the environment can survive in a variety of different conditions

Next….. Nutrition and Energy Flow

Nutrition and Energy Flow

Energy Role in an Ecosystem Determined by: How it obtains energy How it interacts with other living organisms in its ecosystem The sun: provides energy Producers: harness energy from the sun ex. plants Consumers: organisms that eat something else ex. animals Decomposers: return energy to the environment ex. fungus, bacteria

Producers Autotroph: Uses light energy or energy stored in chemical compounds to make energy Grass Trees Green Algae

Consumers Heterotrophs: Feeds on other organisms Herbivores: Eat plants Carnivores: Eat other heterotrophs (meat only) Omnivore: Eat both (meat and plant) Scavengers: Eat animals that are already dead Decomposers: Break down other organism into simpler compounds

Food Chain Berries  Mice  Black bear Simple model Two – Four transfers Trophic Levels—feeding levels

Energy flow through biological systems

Aquatic Food Chain

Food Chains series of events in which one organism eats another and obtains energy

Food Chains Continued Arrows always points in the direction of energy flow 1st organism is always the producer 2nd organism is the consumer that eats the producer Primary consumer 3rd organism is the consumer that eats the 1st level consumer Secondary consumer 4th organism is the consumer that eats the 2nd level consumer Tertiary Consumer And so on…

Energy Pyramid 2nd Law of Thermodynamics: energy is not transferred from one object/organism to the next with 100% efficiency Some of the energy is lost to the environment Energy Pyramid shows the amounts of energy that moves from one level to the next

Sample Energy Pyramid

Energy Transfer Only about 10% of energy is transferred from one level to the next The other 90% is used by the organism to carry out its life processes or it is lost to the environment

Food Web Shows all possible feeding relationships at each trophic level in a community

Aquatic Food Web

Pyramid of Numbers

the total mass of living matter in a given unit area Pyramid of Biomass generally expressed in dry weight (after removal of all water from the sample) per unit area of land or unit volume of water