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Answer questions asked by users of Biology Questions and Answers.

Perhaps a few hundred million years after the first mitochondrion appeared, as the oceanic oxygen content, at least on the surface, increased as a result of oxygenic photosynthesis, those complex cells learned to use oxygen instead of hydrogen. It is difficult to overstate the importance of learning to use oxygen in respiration, called . Before the appearance of aerobic respiration, life generated energy via and . Because oxygen , aerobic respiration generates, on average, about per cycle as fermentation and anaerobic respiration do (although some types of anaerobic respiration can get ). The suite of complex life on Earth today would not have been possible without the energy provided by oxygenic respiration. At minimum, nothing could have flown, and any animal life that might have evolved would have never left the oceans because the atmosphere would not have been breathable. With the advent of aerobic respiration, became possible, as it is several times as efficient as anaerobic respiration and fermentation (about 40% as compared to less than 10%). Today’s food chains of several levels would be constrained to about two in the absence of oxygen. Some scientists have and oxygen and respiration in eukaryote evolution. is controversial.

Plant Energy Transformations-Photosynthesis - …

I. Body Organization
A. Define anatomy and physiology
B. Explain the relationship between anatomy and physiology
C. List the characteristics of life
D. List the factors required for maintenance of life
E. Use accepted anatomical terminology to describe body positions, sections, and regions
F. Locate major body cavities
G. Identify membranes
H. Name the major organ systems and list the organs associated with
I. Identify vital signs
J. Define homeostasis and summarize its significance
K. Describe the systemic approach of study of the human body and organize the body in this format.
II. Cytology
A. Identify the human cell
B. Identify the structures of the human cell
C. List the functions of principle cell structures
D. Summarize the Cell Theory
E. Explain physiological movements through cell membranes
F. Identify the stages of cell division in human cells
G. Demonstrate proper staining of a human cell
H. Identify prepared cells upon presentation
I. Define common cytological terms
III. Histology
A. Identify human tissues types upon presentation
B. Categorize human tissues
C. Describe the functions of each tissue type
D. List locations of tissue types in the body
E. Explain how glands are classified
F. Define common histological terms
IV. Integumentary System
A. List functions of the skin
B. Identify the regions of the skin
C. Identify organs of the integumentary system upon presentation
D. List functions of the integumentary organs
E. Describe factors involved in skin color
F. Distinguish anomalies and pathologies of skin
G. Define common dermatological terms
V. Skeletal System
A. List functions of the skeletal system
B. Identify bone structures
C. Classify bones according to their shape
D. Summarize bone growth and remodeling
E. Recognize divisions of the skeleton
F. Identify bones of the skeleton
G. Identify foramina and processes of bones
H. Distinguish anomalies and pathologies of bone
I. Describe the effects of hormones that act on bone
J. Classify joints based on structure and movement
K. Identify joints
L. Distinguish pathologies of joints
VI. Muscular System
A. List the functions of the muscular system
B. Identify structures within skeletal muscle
C. Describe how muscles structure is organized
D. Identify the muscle organs of the human body upon presentation
E. Summarize the events of muscular contraction
F. Explain how energy is supplied to muscle
G. Summarize muscle fatigue
H. Explain the effect of oxygen on muscle
I. Describe how exercise affects skeletal muscle
J. Identify the three types of muscle
K. Summarize muscle group function
L. Define common terms associated with muscle and kinesiology
M. Distinguish common muscle pathologies
VII. Nervous System
A. List the functions of the nervous system
B. Describe how nervous tissue is organized
C. Identify the types of nerve cells
D. List functions of nerve cells
E. Identify structures within nerve cells
F. Explain how an injured nerve may regenerate
G. Explain nerve cell potentials
H. Summarize the events at a synapse
I. Distinguish between types of post synaptic potentials
J. List factors that affect post synaptic potentials
K. List the components of the reflex arc
L. Summarize the importance of nerve pathway organization
M. Identify the meninges
N. Distinguish between CNS and PNS
O. Identify the organs of the CNS
P. Identify the major parts of the brain and spinal cord
Q. List the functions of the organs of the CNS
R. Distinguish association areas of the cerebral cortex
S. Distinguish between ANS and SNS
T. Summarize the functions of the ANS
U. Distinguish between the sympathetic and parasympathetic divisions of the ANS
V. Identify the nerves of the PNS
W. Distinguish common nervous system pathologies
X. Identify special senses
VIII. Endocrine System
A. Identify organs that secrete hormones
B. Classify glands based on structure
D. Classify glands based on function
E. Explain hormone pathways and regulation
IX. Cardiovascular System
A. Identify the components of blood upon presentation
B. List the functions of each type of blood cell
C. Explain control of red blood cell production
D. List the functions of blood plasma
E. Summarize blood typing procedures
F. Summarize the events in coagulation
G. Identify the structures of the heart
H. Describe the pathway of blood through the heart chambers
I. Explain heart contraction
J. Summarize the events of the conduction system
K. Identify common physiological tests
L. Perform vital signs
M. Identify the types of blood vessels
N. Locate major arteries and veins of the body
O. List functions of each type of blood vessel
P. Distinguish common heart, blood, and vessel anomalies using standard
medical reports
Q. Define terminology used in the medical community relating to
cardiovascular care
X. Digestive System
A. Identify digestive organs, their regions, and structures upon
B. Distinguish between alimentary canal organs and accessory organs
C. List and explain the functions of the digestive system
D. List the functions of each digestive organ
E. Explain how the contents of the alimentary canal are moved
F. Describe common pathologies of digestive organs
G. Summarize factors that affect digestion
XI. Respiratory System
A. Identify respiratory organs, their regions, and structures upon
B. Summarize the events in inspiration and expiration
C. List and explain the functions of the respiratory system
E. Define common respiratory ailments
F. List nonrespiratory air movements
G. Classify respiratory organs as upper or lower tract
H. Explain the exchange of gases at the alveolar level
I. Distinguish common breathing anomalies using standard medical
J. Identify clinical pathologies of the respiratory system
XII. Urinary System
A. Identify urinary organs, their regions, and structures upon
B. List and explain the functions of the urinary system
C. Trace the pathway of blood through the kidney
D. Explain the events of urine formation
E. Summarize the events of micturition
F. Identify common anomalies of the urinary system
XIII. Reproductive System
A. Identify reproductive organs, their regions, and structures upon
B. List the functions of each reproductive organ
C. Identify analogous organs of both gender systems
D. Explain how hormones control sexual characteristics
E. Trace the complete path of sperm cells
F. Trace the complete path of an egg through fertilization and
G. Identify common STDs
H. Lymphatic System
I. Identify lymphatic organs
J. List the functions of the lymphatic system

Biology (BIOL) < Johnson County Community College


All animals, , use aerobic respiration today, and early animals (, which are called metazoans today) may have also used aerobic respiration. Before the rise of eukaryotes, the dominant life forms, bacteria and archaea, had many chemical pathways to generate energy as they farmed that potential electron energy from a myriad of substances, such as , and photosynthesizers got their donor electrons from hydrogen sulfide, hydrogen, , , and other chemicals. If there is potential energy in electron bonds, bacteria and archaea will often find ways to harvest it. Many archaean and bacterial species thrive in harsh environments that would quickly kill any complex life, and those hardy organisms are called . In harsh environments, those organisms can go dormant for millennia and , waiting for appropriate conditions (usually related to available energy). In some environments, it can .

Around when Harland first proposed a global ice age, a climate model developed by Russian climatologist concluded that if a Snowball Earth really happened, the runaway positive feedbacks would ensure that the planet would never thaw and become a permanent block of ice. For the next generation, that climate model made a Snowball Earth scenario seem impossible. In 1992, a professor, , that coined the term Snowball Earth. Kirschvink sketched a scenario in which the supercontinent near the equator reflected sunlight, as compared to tropical oceans that absorb it. Once the global temperature decline due to reflected sunlight began to grow polar ice, the ice would reflect even more sunlight and Earth’s surface would become even cooler. This could produce a runaway effect in which the ice sheets grew into the tropics and buried the supercontinent in ice. Kirschvink also proposed that the situation could become unstable. As the sea ice crept toward the equator, it would kill off all photosynthetic life and a buried supercontinent would no longer engage in . Those were two key ways that carbon was removed from the atmosphere in the day's , especially before the rise of land plants. Volcanism would have been the main way that carbon dioxide was introduced to the atmosphere (animal respiration also releases carbon dioxide, but this was before the eon of animals), and with two key dynamics for removing it suppressed by the ice, carbon dioxide would have increased in the atmosphere. The resultant greenhouse effect would have eventually melted the ice and runaway effects would have quickly turned Earth from an icehouse into a greenhouse. Kirschvink proposed the idea that Earth could vacillate between states.

Energy and the Human Journey: Where We Have Been; …

Garden - How To Information | eHow

An additional pathway for CO2 uptake involves photosynthesis by phytoplankton. The organic carbon produced by phytoplankton moves up the food chain and about 90% is converted eventually to CO2(aq) by respiration and decay within the oceanic mixed layer. The 10% fraction that precipitates (fecal pellets, dead organisms) represents a biological pump transferring carbon to the deep ocean. The biological productivity of the surface ocean is limited in part by upwelling of nutrients such as nitrogen from the deep (), so that the efficiency of the biological pump is again highly dependent on the vertical circulation of the ocean water. It is estimated that the biological pump transfers 7 Pg C yr-1 to the deep ocean, as compared to 40 Pg C yr-1 for CO2(aq) transported by deep water formation.

II. Principles of Science
A. List the ecological levels of the hierarchy of matter.
B. List and describe the five physical characteristics of the biosphere which allow life to exist on Earth.
C. Describe the biomes east and west of Kansas City with respect to limiting factors and vegetation.
D. List the biotic and abiotic components of an ecosystem.
E. Compare and contrast photosynthesis and cell respiration.
F. State the Principle of Competitive Exclusion and the Law of Tolerances.
G. State the Law of Conservation of Matter and the two Laws of Thermodynamics.
H. Describe the application of the Law of Conservation of Matter and the two Laws of Thermodynamics to ecosystems.
I. Describe factors which lead to ecosystem stability.
J. Describe nutrient cycling and the specific of two cycles.

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South University - Campus Savannah campus

The twin ideas of efficiency and resilience are important. Efficiency is about getting more for less, particularly energy. Although aerobic respiration’s energy efficiency allowed for to develop, they end up creating interactions and dependencies, and the entire structure can lose its resilience when compared to simpler systems. Remove one part of the food chain and the entire ecosystem can collapse, and it can be part of the chain, from top to bottom. Making systems more efficient, as the last bits of energy are wrung from the system, reduces their resilience to the real world’s surprises. That dynamic is probably a key contributing factor of mass extinctions during the eon of complex life. Modern ecosystems studies are making the connections clear and are being applied to the dynamics of human civilizations; work has been seminal in this regard. Complex ecosystems pass through of exploitation, conservation, release, and reorganization, and three dimensions of interaction are involved: potential, connectedness, and resilience. In general, simple systems are more stable than complex ones, which is another reason why any , if there were any, would have been far less cataclysmic than those of complex life.

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