SIX UNIFYING THEMES OF BIOLOGY

1. Biology is unified by certain themes, that come into play No Matter what Organism or What Kind of Interaction is studied. The SIX MAJOR THEMES recur throughout our textbook:

    A. Interdependence of Organisms
    B. Matter, Energy, and Organization

C. Cell Structure and Function
  D. Stability and Homeostasis
    E. Reproduction and Inheritance
    F. Evolution (Change)

A. INTERDEPENDENCE OF ORGANISMS

BIOLOGY - the Science of Life - is The Study of ALL Living Things.

WHAT IS ECOLOGY?

1. Ecology comes from the GREEK Words OIKOS (HOUSE OR PLACE WHERE ONE LIVES) and LOGOS (STUDY OF).

2. Ecology then means the study of the "House" in which we live.

3. Ecology can be defined more specifically as the Study of the Interactions between Organisms and the Nonliving Components of their Environment.

4. The Earth includes a tremendous variety of living things. Each organism depends in some way on other living and nonliving things in its environment.

5. Ecology involves collecting information about organisms and their environment, looking for patterns, and seeking to explain these patterns.

LEVELS OF ORGANIZATION

1. The surface of the Earth as a whole is an Ecosystem.  We call the Surface of the Earth the BIOSPHERE.

2. The Biosphere is the surface of the Earth (AIR, WATER, and LAND) Where Living Things Exist.

A. Hydrosphere: the water of the earth

B. Lithosphere: the earth’s outer rocky layer

C. Atmosphere: the gases and airborne particles that surrounds the earth

3. There is an uneven distribution of organism throughout the biosphere.

4. The Biosphere is composed of smaller units called ECOSYSTEMS. An ecosystem includes all the organisms and the nonliving environment found in a particular place.

5. Ecosystems can be as large or as small as we decide.  Any area you decide to study can be considered an ecosystem.

6. For example you may choose to study your back yard, Elkhorn Creek, or the KY River. Any of these would be considered an Ecosystem.

7.  A POPULATION includes all the members of the same species that live in one place at one time.

8. Populations are individual species, all the interacting organisms (All The Different Populations) that live in a particular area make up a COMMUNITY. The physical location of a community is called the HABITAT.

9. The simplest level of organization in Ecology is that of the ORGANISM.

10. The Diversity of an Ecosystem is a measure of the number of different species there, and how common each species is.

11. Ecosystems are very complex.  They can contain hundreds or even thousands of interacting species.

FLOW OF ENERGY IN ECOSYSTEMS

1. The MOST Important Factor Determining how many and what kind of organisms that can live in an Ecosystem is the amount of ENERGY Available.

2. The amount of energy an ecosystem receives and the amount that is transferred from organism to organism has an important effect on the ecosystem’s structure.

3. All organisms need energy to carry out essential functions, such as growth, movement, maintenance and repair, and reproduction.

4. Energy in an ecosystem FLOWS from the SUN to Autotrophs (Producers) then to organisms that eat the Autotrophs, then to organisms that feed on other Organisms (Consumers).

5. The Primary source of energy for an ecosystem is the SUN.

6. Producers are Autotrophic organisms (Autotrophs) with the capability of carrying out photosynthesis, and making food for themselves and storing some for other organisms to consume. 

A. Photoautotroph: grasses, plants

B. Chemoautotroph: use electrons from inorganic substances; some bacteria

7. All other organisms in ecosystem are Consumers or Heterotrophs that eat the Producers or other organisms.

8. Heterotrophs or Consumers can be broken into different groups depending on what they EAT:

A. Primary consumers: get their food directly from primary producers (herbivores)

B. Secondary consumers: feed on primary consumers. Also called primary carnivores; spiders, foxes

C. Tertiary consumers: feed on primary carnivores; emperor penguin, killer whale

D. Decomposers – Consumers who feed on remains of dead plants and animals.

E. Omnivores – Eat both producers and consumers. Plant and meat eaters (humans).

F. Detritivores – Feed on the "Garbage" of an ecosystem.

9. In an Ecosystem these Producers and Consumers are placed in Trophic Levels (Feeding Levels).

10. A Trophic Level is a group of organisms whose feeding source is the same number of steps from the Sun.

    A. Producers (Autotrophs) are the first Trophic Level.

    B.  Herbivores are the second Trophic Level.

    C.  Carnivores are the third, fourth and fifth Trophic Levels.

11. Most Animals (Carnivores) feed at more than one Trophic Level.

12. Energy Flows through an ecosystem in a complex network of feeding relationships called a FOOD WEB.

13. A FOOD CHAIN indicates who eats whom in an ecosystem.  A Food Web may contain several Food Chains.

14. Energy is Lost or Used as it flows through the Trophic Levels of an ecosystem.

15.  Producers (plants) absorb energy from the sun, but only about ˝ of the Energy capture from the Sun becomes part of the plants body.  The other ˝ is used for living and growing or lost as HEAT.

16.  At each Trophic Level, the Energy stored in an organism is about 1/10 that of the Level Below it (10%).

17.  Because energy diminishes at each successive Trophic Level, few ecosystems can contain more than 4 or 5 Trophic Levels.

18. Organisms at Higher Trophic Levels, large carnivores, tend to be fewer in number than those at lower Trophic Levels, producers.

COMMUNITIES AND ECOSYSTEMS

COMMUNITIES

· Populations interact with one another. Mostly indirectly (soup can, dumpster, mosquito).

· The set of interacting populations present during one time in one place is called a community.

§ The size of a community is affected by the amount of energy entering it through its producers.

§ Net Primary productivity is the measure of the total dried mass of living organisms. Fresh peach vs. dried peach (same energy amount, because water is not an energy source). The higher the NPP, the more consumers can live in the community.

§ Carrying capacity limits the number of organisms that can live in a community.

§ Usually the total mass of producers is much larger than the consumers

§ On an energy pyramid, 90% of the energy of the level below is lost at each step.

· Every community is affected by 2 different kind of factors:

BIOTIC AND ABIOTIC FACTORS

1. An Ecosystem possesses both LIVING COMPONENTS OR BIOTIC FACTORS and NONLIVING OR ABIOTIC FACTORS.

2. The Nonliving Factors, called Abiotic Factors, are physical and chemical characteristics of the environment. They include solar energy (amount of sunlight), oxygen, CO2, water, temperature, Humidity, pH, and availability of nitrogen.

3. The Living components of the environment are called Biotic Factors. They include all the living things that affect an organism. Biotic components are often categorized as Producers, Consumers, and Decomposer.

ECOSYSTEMS

Ecosystems: smaller units of the biosphere which consists of a given area’s physical features (abiotic factors) and living organisms (biotic factors).

o Ecosystems are not self-contained! They are connected with other ecosystems. Their boundaries are very hard to define

o Ecosystems change over a period of time, WHY? Every organism affects the environmental conditions around it.

o Ecological succession is the process where a different community replaces an existing community of organisms over a period of time (decades to thousand of years).

§ Also it can occur where no living community existed before. Example: volcanic island

§ Climax community is a stable collection of organisms as result of succession.

THE NICHE

1. Each organism or species in the community has a ROLE or PROFESSION in that community and in Ecology this is the organism NICHE.

2. A species’ niche is its way of life, or the role the species plays in its environment.

3. The niche includes the range of conditions that the species can tolerate, the methods by which it obtains needed resources, the number of offspring it has, its time of reproduction and all its other interaction with its environment.

4. The FUNDAMENTAL NICHE is the range of conditions that a species can potentially tolerate and the range of resources it can potentially use.

5. The REALIZED NICHE of a species is the range of resources it actually uses.

6. GENERALIST are species with broad niches; they can tolerate a range of conditions and use a variety of resources. Species that have narrow niches, such as the Koala, are called SPECIALIST.

7. No 2 organisms can occupy the same niche within a community for a long period of time

8. Habitat: is where the organism lives

Animal Behavior

Learning is the acquiring of information or a behavior that was not previously a part of the organism

· Conditioning is exhibiting a behavior as a result of a respond to a particular set of conditions, known or unknown, usually called a stimulus

o Classical or associative behavior. Pavlov’s classical salivating dog experiment (responding to a substitute stimulus)

o Operant is a trial and error conditioning. The closer an individual gets to the desired response with positive reinforcement, the more he will repeat the response. Animal training.

· Habituation is to disregard a stimulus because of unproductive results. Birds in city do not flee from people (pigeons)

· Insight an animal performs a successful behavior without any previous experience. Chimpanzees.

· Observational individuals copy the behavior of another without having experienced the stimulus before that produces that behavior.

Innate are behaviors that already exists inside the individuals

· Imprinting occurs only if the right stimulus occurs during a particular time. Salmon, baby geese, etc.

· Instinct is an inherited behavior (no other explanation). Cuckoo birds, a social parasite deposits her eggs on other species nests. Newborn babies push existing eggs out of the nest so they can get all the attention from the host mother. Human babies and faces.

Movement

· Kinesis is a random change in speed or direction of an organism in response to a stimulus. Speed up in unfavorable environment, slow down in favorable one.

· Taxis is a very specific response to a stimulus. Stay or flight response.

· Group or migration is the movement of animals determine by seasonal influences, usually food availability.

Communication is needed to recognize one’s own kind for mating or for social behavior (avoiding a predator). Termite example: workers banged their heads against the tunnel when it is ruptured. This warns the soldiers who start to shoot goo from their nose.

· Chemical communication releases pheromones, which trigger a response when smelled or eaten. Working bees eat the pheromone not allowing them to reproduce.

· Visual communication is seen during courtship or aggressive behavior

· Auditory

· Tactile use for bonding, infant care, and mating.

Feeding

· Groups

o Herds use this kind of group behavior when feeding as a means of defending against predators by shielding each other.

o Packs engage in group hunting. Smaller attacking a larger one.

· Search Image is like looking for your car in a crowded parking lot.

Social

Disadvantages: low reproduction success; little food; more diseases

Advantages: cooperative predator avoidance (musk oxen); selfish herd (strong in the middle)

· Agonistic behavior is aggressive/ submissive behavior that actually has great survival rate.

· Dominance established hierarchies (pecking order)

· Territoriality ensures a food supply, a place for reproductive activities and raise of infants.

· Altruistic is an unselfish behavior that actually increases the fitness of the group by ensuring the survival of the species.