Xylem and Phloem

The xylem is the principal water-conducting tissue of vascular plants. It consists of tracheary elements, tracheids and wood vessels and of additional xylem fibres. All of them are elongated cells with secondary cell walls that lack protoplasts at maturity. Bordered pits are typical for tracheids, while wood vessels are marked by perforated or completely dissolved final walls.

Phloem is the vascular tissue plants use to transfer sugars from sites of production or storage to locations where energy is needed. In contrast to xylem, phloem tissues are living. Sieve tube members connect at specialized areas called seive plates. At maturity the seive tube members lose their nuclei and fill with a complex proteinaceous material called cell sap. Sugars are transported through the cell saps of adjacent cells.

In losing their nuclei, sieve tube members lack the molecular control mechanisms most living cells possess. Nucleated cells adjacent to sieve tube members appear to take over the control of cellular functions within these phloem transport cells. These nucleated cells are appropriately called companion cells.

Sieve plates are specialized areas where materials flow through tiny pores from one sieve tube member to another.
Most phloem cells are parenchyma cell types. Sometimes phloem tissues contain sclerenchyma fibers for support.

External and Internal Parts of Plant Organs

Plant Hormones

Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Example: Indole Acetic Acid (IA). Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant. This produces a curving of the plant stem tip toward the light, a plant movement known as phototropism.

Auxin also plays a role in maintaining apical dominance. Most plants have lateral (sometimes called axillary) buds located at nodes (where leaves attach to the stem). Buds are embryonic meristems maintained in a dormant state. Auxin maintains this dormancy. As long as sufficient auxin is produced by the apical meristem, the lateral buds remain dormant. If the apex of the shoot is removed (by a browsing animal or a scientist), the auxin is no longer produced. This will cause the lateral buds to break their dormancy and begin to grow. In effect, the plant becomes bushier. When a gardener trims a hedge, they are applying apical dominance.

Gibberellins promote stem elongation. They are not produced in stem tip. Gibberellic acid was the first of this class of hormone to be discovered.

Cytokinins promote cell division. They are produced in growing areas, such as meristems at tip of the shoot.

Abscisic Acid promotes seed dormancy by inhibiting cell growth. It is also involved in opening and closing of stomata as leaves wilt.

Ethylene is a gas produced by ripe fruits. Why does one bad apple spoil the whole bunch? Ethylene is used to ripen crops at the same time. Sprayed on a field it will cause all fruits to ripen at the same time so they can be harvested.

Dark Reaction of Photosynthesis: Puzzle

Photosynthesis word search game » word search puzzle maker

Nine Environmental Principles

1. Nature knows best
This principle is the most basic and, in fact, encompasses all the others. In essence people must not go against the natural process if they would like to ensure a continuous and steady supply of resources. In nature, nutrients pass from the environment to the organism and back to the environment. Any disruption in the cycle can bring about imbalance. For example, burning of farm wastes instead of allowing them to decompose naturally disrupts the cycle.

2. All forms of life are important.
Each organism plays a fundamental role in nature. All living things must be considered valuable in the maintenance of stability in an ecosystem. It is easy to appreciate the beautiful butterflies, especially knowing their important role in pollination. Giant beasts like whale, alligator, and elephant are objects of wonder and respect.

3. Everything is connected to everything else.
In an ecosystem, all components interact with each other to ensure the system is continued. Any outside interference may result in an imbalance. Deforestation in the mountains may affect the lowlands, resulting in floods, drought, or erosion. What happens in one country may even affect other countries.

4. Everything changes.
The only permanent thing is change. Change may be linear, cyclical, or random. An example of linear change is the evolution of a species. Cyclical changes is the eruption of a volcano, like Mt. Pinatubo bringing great upheaval in many parts of Luzon.

5. Everything must go somewhere.
When a piece of paper is thrown away, it disappears from sight but it does not cease to exist. It simply goes somewhere else. Wastes can either be pollutants or resources. We need to change or "throw-away" society attitude in order to develop better methods of waste management and recycling.

6. Ours is a finite earth.
The earth's resources can be classified as either renewable or nonrenewable. Renewable resources, like water, air, plants, and animals, can easily be replenished by natural cycles. Nonrenewable resources, like minerals, oil, and coal cannot be replenished through natural cycles. Awareness of the earth's limited resources should lead to a conscious effort to change one's attitude as a consumer.

7. The amount of life nature can support is limited.
Carrying capacity is the maximum number of individuals of a given species which can be supported by a particular habitat or ecosystem without damaging it. For example, a typical Filipino bahay kubo can only support a limited number of family members; the presence of too many residents results in overcrowding. Therefore, nature nature has its own processes or mechanisms to regulate the population of a species within or environment.

8. Human progress must consider its effect on nature.
Sustainable development meets the needs of the present without comprising the ability of future generations to meet their own needs. Development is viewed as essential in improving the quality of human life, yet human activities often change the environment and destroy or damage natural resources. Sustainable development strives for human progress without threatening the environment.

9. Nature is beautiful and we are stewards of God's creation.
This principle is inherent in most religious and tribal beliefs. teachings of Christianity, Buddhism, and Islam enjoin everyone to respect all life and order of nature.

NOTE: Guys, you will work by three or by four. Think of a situation or a scenario on how you can role play or simulate the each principle of environment. You will perform on Monday.

Branches of Biology

These are the main branches of biology:[65][66]

* Aerobiology - study of airborne organic particles

* Agriculture - study of producing crops from the land, with an emphasis on practical applications

* Anatomy - the study of form and function, in plants, animals, and other organisms, or specifically in humans

* Astrobiology- the study of evolution, distribution, and future of life in the universe. Also known as exobiology, exopaleontology, and bioastronomy.

* Biochemistry - the study of the chemical reactions required for life to exist and function, usually a focus on the cellular level

* Bioengineering - the study of biology through the means of engineering with an emphasis on applied knowledge and especially related to biotechnology.

* Bioinformatics - the use of information technology for the study, collection, and storage of genomic and other biological data

* Biomathematics or Mathematical Biology - the study of biological processes through mathematics, with an emphasis on modeling.

* Biomechanics - often considered a branch of medicine, the study of the mechanics of living beings, with an emphasis on applied use through artificial limbs, etc.

* Biomedical research - the study of the human body in health and disease

* Biophysics - the study of biological processes through physics, by applying the theories and methods traditionally used in the physical sciences

* Biotechnology - a new and sometimes controversial branch of biology that studies the manipulation of living matter, including genetic modification

* Building biology - study of the indoor living environment

* Botany - the study of plants

* Cell biology - the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell.

* Conservation Biology - the study of the preservation, protection, or restoration of the natural environment, natural ecosystems, vegetation, and wildlife

* Cryobiology - the study of the effects of lower than normally preferred temperatures on living beings.

* Developmental biology - the study of the processes through which an organism forms, from zygote to full structure.

* Ecology - the study of the interactions of living organisms with one another and with the non-living elements of their environment.

* Embryology - the study of the development of embryo (from fecondation to birth). See also topobiology.

* Entomology - the study of insects

* Environmental Biology - the study of the natural world, as a whole or in a particular area, especially as affected by human activity

* Epidemiology - a major component of public health research, it is the study of factors affecting the health and illness of populations

* Ethology - the study of animal behavior.

* Evolutionary Biology - the study of the origin and descent of species over time

* Genetics - the study of genes and heredity.

* Herpetology - the study of reptiles and amphibians

* Histology - the study of cells and tissues, a microscopic branch of anatomy.

* Ichthyology - the study of fish

* Integrative biology - the study of whole organisms

* Limnology - the study of inland waters

* Mammalogy - the study of mammals

* Marine Biology - the study of ocean ecosystems, plants, animals, and other living beings.

* Microbiology - the study of microscopic organisms (microorganisms) and their interactions with other living things

* Molecular Biology - the study of biology and biological functions at the molecular level, some cross over with biochemistry

* Mycology - the study of fungi

* Neurobiology - the study of the nervous system, including anatomy, physiology, even pathology

* Oceanography - the study of the ocean, including ocean life, environment, geography, weather, and other aspects influencing the ocean.

* Oncology - the study of cancer processes, including virus or mutation oncogenesis, angiogenesis and tissues remoldings

* Ornithology - the study of birds

* Population biology - study of the populations of organisms - most often referred as ecology, or used to point out biology adaptations, biology events sum up

* Population ecology - the study of populations of organisms, including how they increase and go extinct (dynamics

* Population genetics - the study of changes in gene frequencies in populations of organisms

* Paleontology - the study of fossils and sometimes geographic evidence of prehistoric life

* Pathobiology or pathology - the study of diseases, and the causes, processes, nature, and development of disease

* Parasitology - the study of parasites and parasitism

* Pharmacology - the study and practical application of preparation, use, and effects of drugs and synthetic medicines.

* Physiology - the study of the functioning of living organisms and the organs and parts of living organisms

* Phytopathology - the study of plant diseases (also called Plant Pathology)

* Psychobiology - study of the biological bases of psychology

* Sociobiology - study of the biological bases of sociology

* Structural biology - a branch of molecular biology, biochemistry, and biophysics concerned with the molecular structure of biological macromolecules

* Virology - the study of viruses and some other virus-like agents

* Zoology - the study of animals, including classification, physiology, development, and behavior (See also Entomology, Ethology, Herpetology, Ichthyology, Mammalogy, and Ornithology)

Respiratory System

The Pathway

* Air enters the nostrils
* passes through the nasopharynx,
* the oral pharynx
* through the glottis
* into the trachea
* into the right and left bronchi, which branches and rebranches into
* bronchioles, each of which terminates in a cluster of
* alveoli

Only in the alveoli does actual gas exchange takes place. There are some 300 million alveoli in two adult lungs. These provide a surface area of some 160 m2 (almost equal to the singles area of a tennis court and 80 times the area of our skin!).


Breathing
In mammals, the diaphragm divides the body cavity into the

* abdominal cavity, which contains the viscera (e.g., stomach and intestines) and the
* thoracic cavity, which contains the heart and lungs.

The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse. This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, reinflation occurs as the air is gradually absorbed by the tissues.
Because of this adhesion, any action that increases the volume of the thoracic cavity causes the lungs to expand, drawing air into them.

* During inspiration (inhaling),
o The external intercostal muscles contract, lifting the ribs up and out.
o The diaphragm contracts, drawing it down .
* During expiration (exhaling), these processes are reversed and the natural elasticity of the lungs returns them to their normal volume. At rest, we breath 15-18 times a minute exchanging about 500 ml of air.
* In more vigorous expiration,
o The internal intercostal muscles draw the ribs down and inward
o The wall of the abdomen contracts pushing the stomach and liver upward.
Under these conditions, an average adult male can flush his lungs with about 4 liters of air at each breath. This is called the vital capacity. Even with maximum expiration, about 1200 ml of residual air remain.