Evolution & Origin of Life: Theories, Experiments & Evidence
Evolution & Origin of Life
Early Experiments & Theories
Redi’s Experiment
Francesco Redi investigated the spontaneous generation of maggots by placing meat in three jars: one open, one covered with fabric, and one sealed. Maggots only appeared in the open and fabric-covered jars, suggesting they arose from flies, not spontaneously.
Pasteur’s Experiment
Louis Pasteur further disproved spontaneous generation by using swan-neck flasks containing sterilized broth. The broth only decomposed when exposed
Read MoreBlood Circulation and Internal Environment in Human Beings
1. Internal Environment
Internal environment is those that provides all cells with all the nutrients they need. The internal environment in human beings is formed by:
- Interstitial plasma. It is a liquid substance that fills the existing spaces between cells. Interstitial plasma needs to be renewed continuously, because new nutrients need to be provided and waste products can’t be allowed to accumulate and must be released. Blood renews interstitial plasma given that it circulates around the whole
Understanding Environmental Factors and Adaptations
Environmental Factors
The characteristics of the environment that affect living things are called environmental factors. They can be biotic or abiotic.
Biotic/Abiotic Factors
Abiotic factors are the physical and chemical conditions that affect living things: water, temperature, light, soil, pH, humidity, and nutrients found in soil or water.
Biotic factors are the organisms that share the same natural environment.
Intraspecific Relationships
Those between individuals of the same species.
Interspecific
Read MoreChordates: Characteristics, Classification, and Evolution
Chordates: Characteristics and Classification
Basic Characteristics of Chordates
All chordates share four basic characteristics:
- Dorsal Notochord: A long supporting rod that runs through the body just below the nerve cord. Most chordates have a notochord only when they are embryos.
- Dorsal Hollow Nerve Chord: The cord runs along the back of the body. Nerves branch from this cord at regular intervals and connect to internal organs, muscles, and sense organs.
- Pharyngeal Pouches: Paired structures in the
Human Sensory Organs and Effectors: Functions and Structures
The Eye
The eye receives light where the photoreceptors are located. Photoreceptors in the eye transform stimuli into electrical impulses and transmit the information to the optic nerve.
- Lens: transparent and elastic organ
- Retina: innermost layer, two types of photoreceptor cells (rods and cones)
- Choroid: second layer, the iris appears colored. In the center of the iris there is an orifice called pupil.
- Sclera: outermost layer, frontal part (transparent, forming the cornea)
- Fovea: best visibility
- Blind
Pharmaceutical Processes and Techniques
Construction
The body of a double cone mixer consists of two cone-shaped sections joined to a central section. The rotational axis is perpendicular to the cone axis and passes through the central section. The blender body is held by two lateral supports, one of which is fitted with the driving motor.
Working
The double cone blender is attached to the two lateral supports to prevent movement of the mixture. The materials are then loaded, and the lid of the blender is closed. The equipment is then switched
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