Harmful Algal Blooms, Echinoderms, Mollusks, and Eutrophication
Harmful Algal Blooms
Harmful Algal Blooms (HABs) are the result of the rapid multiplication of a single species of microorganisms known as photosynthetic microalgae. This proliferation reaches millions of cells per liter and can be colored by pigments on the cell surface, hence the popular name “Red Tide.” Those blooms produced by microalgae that are present in different oceans across the globe and are capable of producing potent toxins are termed Harmful Algal Blooms, a term coined by the Intergovernmental
Read MoreKingdom Classification of Living Organisms
Chronology of Classifications
Living things were initially classified into two kingdoms: Animalia and Plantae. However, with scientific advancements, it became apparent that some organisms could not be assigned to either of these two kingdoms. Haeckel suggested the establishment of the kingdom Protista to group all unicellular organisms whose characteristics did not fit either plants or animals. This included bacteria, which were later separated into another kingdom named Monera, encompassing single-
Read MoreUnderstanding the Respiratory System: Mechanisms and Control
Dorsal Respiratory Group Neurons
The dorsal respiratory group controls inspiration and breathing rate. It is located in the dorsal portion of the medulla and extends along it. It is mainly stimulated by inspiration. Most of its neurons are located in the nucleus of the solitary tract, where the vagus and glossopharyngeal nerves terminate. These nerves transmit signals to the nucleus from:
- Peripheral chemoreceptors
- Baroreceptors
- Several types of lung receptors
They are responsible for generating the respiratory
Read MoreNerve Impulse Transmission and Nervous System Evolution
Transmission of Nerve Impulses from Neuron to Effector Organs
The transmission of nerve impulses to effector organs is conducted similarly to what happens at the synapse. Neurotransmitters are released into the effector organs. Thus, effectors respond to the presence of the neurotransmitter, causing a muscle to contract or producing a secretion in the case of a gland.
Invertebrate Nervous System
As one ascends the evolutionary scale, the nervous system acquires greater complexity:
- It tends to direct
Ecosystems and Living Organisms: Interactions and Adaptations
Understanding Ecosystems and Their Components
All living things that inhabit our planet belong to a species. Individuals of the same species can breed with each other and produce fertile offspring. Individuals of the same species living in the same area form a population. The set of populations that share a territory and establish relationships with each other is called a community or biocenosis. The territory occupied by a biocenosis, which has specific physical and climatic characteristics, is
Read MoreCellular Reproduction and Biological Development: A Comprehensive Study
**Asexual Reproduction**
- Occurred 3500 million years ago
- Involves mitosis
- One progenitor
- Normal cells
- Simple and profitable reproduction system
- Genetically identical individuals
- Recombination of genes, not characters
- Rapid growth in the number of individuals
**Sexual Reproduction**
- Occurred 1500 million years ago
- Involves meiosis
- Almost always two parents
- Special cells
- Constructive and very complicated reproductive expenditure
- Genetically different individuals
- Easy recombination of genes and characters