The living environment inspires infinite questions. How many species really exist, how do species live and interact with one another, how do they reproduce, and what happens to the species if it dies? Scientists work to help us answer these questions. But here are some basic facts to help you better understand the living environment.
- Diversity of Life. The diversity of life, or biodiversity, includes the different life forms within a habitat, may it be an ecosystem, a biome, or the earth itself. The species today are products of almost 3.5 billion years of evolution. Species can generally be classified as plants or animals. There are over 350,000 species of plants, some of which are still unidentified. Ecosystems can be studied more through curricula in environmental science.
- Heredity. Heredity is the passing of traits from the parent or ancestor to an offspring. The process of inheritance can be classified, namely by the number of positions on a chromosome that may be occupied by one or more genes, by the structure of DNA and protein in cells, or by the genetic constitution or the observable characteristics of a life form. For instance, a man with blue eyes creates an offspring with a woman with brown eyes. In order for the offspring to have blue eyes, he must inherit the dominant gene for blue eyes from his father, and the recessive gene for brown eyes from his mother. In order for him to have brown eyes, he must inherit the dominant gene for brown eyes from his mother, and the recessive gene for blue eyes from his father.
- Cells. The cell is the smallest unit of life. All living organisms are made of one cell or more. Cells can reproduce through binary fission or mitosis, or meiosis. They can take in raw materials and convert them into energy for metabolic use. They can also respond to stimuli. Cells can be classified as eukaryotic or prokaryotic. Eukaryotic cells are bigger than prokaryotic cells. Eukaryotes contain compartments lined by membranes where metabolic activities happen, while prokaryotes don't. Cells are so small that you need the help of microscopes in labs in order to see them.
- Interdependence of Life. All species in an ecosystem are linked together. They benefit each other, in one way or another. Food chains or food webs show the interdependence of life in an ecosystem. For instance, a plant gets consumed by a caterpillar, the caterpillar gets consumed by a frog, the frog gets consumed by a snake, and the snake gets consumed by the owl. When the owl dies, it decomposes and its nutrients enter into the soil, which then gets consumed by plants.
- Flow of Matter and Energy. Matter and energy in an ecosystem goes in a cycle. No matter or energy should be wasted, in order to have a balanced ecosystem. Here is an example of how matter and energy goes in a cycle. The sun radiates solar energy. The banana tree then absorbs it and converts it into carbohydrates. The monkey consumes the banana, which contains carbohydrates and converts them into chemical energy. The monkey's muscle cells take in the chemical energy, and as the muscle contracts, it converts the chemical energy into mechanical energy and heat flow. When the monkey swings from one tree to another, the mechanical energy gets converted to kinetic energy. The monkey's heat flow, on the other hand, gets dispersed to the surrounding air.
- Evolution of Life. The evolution of life can be divided into eons. The Hadaen eon, 3800 MYA and earlier, was when the earth was formed. Prokaryotic-like cells known as chemoautotrophs appear on the earth. These are the very first organisms. The Archean eon, 3800 MYA to 2500 MYA, was when photosynthesizing bacteria evolved. The Proterozoic eon, 2500 MYA to 542 MYA, was when the first eukaryotes appeared. The rate of evolution increased because of sexual reproduction, and animals started appearing on earth. The Phanerozoic eon, 542 MYA to present, can be classified into eras. The Paleozoic era, 542 MYA to 251.0 MYA, was when insects, sharks, and vegetation evolved. The mesozoic era was the start of the marine revolution. Gymnosperms, viruses, and angiosperms evolved. the Cenozoic era, 65.5 MYA to present, was when all dinosaurs, excluding the birds, were eradicated. Grasses and anatomically modern humans evolved. Biologists can be considered as the living books of the study of the evolution of life.
It has been billions of years since the earth was formed. But up to know, a lot of questions about our living environment still remain unanswered.