Notes, summaries, assignments, exams, and problems for Biology

Myth 1: Everything is an Adaptation Produced by Natural Selection

We tend to assume that all characteristics of plants and animals are adaptations that have arisen through natural selection. Many are neither adaptations nor the result of selection at all.

Argument 1: Not everything is an adaptation

→ Male nipples

Argument 2: Multi-Skilled Genes

We have multi-skilled genes which have more than one function.

Myth 2: Natural Selection Is the Only Means of Evolution

Before we were told all of the 10 facts were myths, we already thought this was not right, because science can also change evolution with the advanced technology we have nowadays.

Myth 3: Evolution Leads to Ever-Greater Complexity

→ No -. Evolution gets rid of what we don’t use (example:... Continue reading "Debunking Common Myths About Evolution" »

The Endocrine System

Why do we need the endocrine system?

The endocrine system functions to secrete hormones directly into the circulatory system to be carried towards distant target organs. These hormones are transported by the circulatory system to regulate physiology and behavior.

What is the endocrine system made of?

It is composed of various organs and glands.

What do glands need to secrete hormones?

These glands secrete hormones to regulate many bodily functions, including growth and metabolism.

How is hormone secretion controlled?

Once the stimulus is over, the secretion of hormones ends. This is controlled through:

• Feedback mechanisms
• Other glands

Main Glands and the Hormones They Secrete

• Pineal Gland: Melatonin
• Pituitary Gland: ACTH
• Thyroid Gland:

Hemangiomas: Congenital Vascular Anomalies

Epidemiology and Onset

• Newborns: 1.1% - 2.6%
• Infants: 10.1%
• Gender Ratio: Girls to Boys (3:1)

Onset occurs in the first year of life. Slow reduction until complete disappearance is possible from Year 2.

Complications

• Ulceration
• Infection
• Bleeding

Treatment Options

1. Spontaneous reduction: Possible without cosmetic or functional consequences.
2. Conservative treatment:
   • Compression Therapy: Used for the trunk, extremities, or abdomen (Note: can cause thrombosis).
   • Laser Therapy: Treatment of surface port-wine stains.
   • Sclerotherapy: Liquid nitrogen.
3. Surgery: Surgical intervention when necessary.

Angiomatosis

General Characteristics

• Wide damage zone.
• Internal visceral organs are affected.

Common Locations

• Extremities
• Abdominal wall
• Perineum
• Buttocks

Clinical

Transgenic Vaccines

Transgenic vaccines are vaccines in which an extracted gene from an organism is introduced into a unicellular organism's genetic code (a bacteria or yeast). This is done to produce a certain protein (the one from the extracted gene) and to multiply that bacteria and the production of the protein in larger quantities. That protein is then able to produce the weakened protein of the membrane of the virus.

Steps of Production

The gene is extracted from the organism and introduced into the seed of the plant, meaning it's introduced inside the first genetic information of the plant. Then you need to plant the seed and allow for the production of the protein.

Advantage of Transgenic Vaccines by Yeasts Over Injured Viruses

They stimulate... Continue reading "Introduction to Biotechnology and Evolution" »

Real and Apparent Origins

Cranial nerves have a real origin, which is the nucleus of gray substance inside the brain, except for cranial nerves I, II, and VIII, whose real origin is outside the brain. The apparent origin is the attachment surface of the brainstem.

Specific Cranial Nerves

Olfactory Nerve (CN I)

Origin: Roof of the nasal cavity.

Optic Nerve (CN II)

Origin: Ganglionic cells of the retina.

Oculomotor Nerve (CN III)

Origin: Sulcus on the medial side of the cerebral peduncle.

• Superior division: Supplies the superior rectus and levator palpebrae superioris.
• Inferior division: Supplies the medial rectus, inferior rectus, and inferior oblique muscle.
• Function: Parasympathetic innervation, constricts the pupil via the ciliary ganglion.

Trochlear

Functions of the Blood

Transports nutrients and oxygen to all the cells and collects waste products produced by cell metabolism. Contributes to the regulation of body temperature. Plays a role in the fight against infections.

Cardiovascular System

Shares nutrients and oxygen between cells and collects waste products that cells produce during metabolism.

Puberty begins with the first ejaculation (spermache) and the first menstruation (menarche).

-Menopause (50), andropause (50)

Reproductive Tract

• Epididymis: Formed by the seminiferous tubes, where sperm mature.
• Ductus referens: Continuation of the epididymis and ascends up to the abdomen. It is used to store sperm.
• Urethra: Also part of the urinary tract connecting the bladder to the exterior.

Accessory Glands

• Seminal vesicles: Flow into ductus deferens, secrete spermatic fluid.
• Prostate: Secretes prostatic fluid which consists of substances to protect sperm from the acidity of the vagina.
• Cowper's glands: A pair of glands that secrete a lubricating fluid that facilitates sexual intercourse.

Reproductive Tract

• Fallopian tubes: Two small tubes located

Arthropod Characteristics

Arthropods are coelomate, segmented, invertebrate animals exhibiting bilateral symmetry. They possess an exoskeleton and jointed appendages. They were the earliest invertebrates to have jointed appendages.

Respiration Methods

1. Sensory Receptors

Sensory receptors are responsible for perceiving information, which they convert into a nerve impulse. The nerve impulse travels to the brain and produces feeling.

1.1. Types of Sensory Receptors

Sensory receptors can be classified according to the stimuli that they can receive, or by where they are located.

1.1.1. According to the Stimuli

• Photoreceptors: They detect light stimuli and are located in the eye.
• Mechanoreceptors: They are stimulated by mechanical changes such as pressure, contact, or sound waves.
• Chemoreceptors: They respond to chemical changes.
• Thermoreceptors: They detect temperature changes.

1.1.2. According to Their Location

• Internal receptors: They are located in the internal organs where they collect information

1. The term anaerobic means