2015-10-13
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The diversity of living things on Earth is referred to as biodiversity. Almost everywhere biologists have looked on this planet — from the deepest, darkest caves to the lush Amazonian rain forests to the depths of the oceans — they’ve found life. In the deepest, darkest caves where no light ever enters, bacteria obtain energy from the metals in the rocks. In the Amazonian rain forest, plants grow attached to the tops of trees, collecting water and forming little ponds in the sky that become home to insects and tree frogs. In the deep oceans, blind fish and other animals live on the debris that drifts down to them like snow from the lit world far above. Each of these environments presents a unique set of resources and challenges, and life on Earth is incredibly diverse due to the ways in which organisms have responded to these challenges over time.
Ex. 38. Fill the gaps with the words from the list below. Be ready to interpret the text.
classes, domains, kingdoms, families, orders, phyla, species, genera
Being able to categorize the three largest, and most distantly related, groups of living things on Earth into domains (as explained in the preceding section) is great, but biologists need smaller groups to work with in order to determine how similar different types of organisms are. Hence the creation of the taxonomic hierarchy, a naming system that ranks organisms by their evolutionary relationships. Within this hierarchy, living things are organized into the largest, most-inclusive group down to the smallest, least-inclusive group.
The taxonomic hierarchy is as follows, from largest to smallest. (Note that organisms are placed into each category based on similarities within that particular group of organisms. Whatever characteristics are used to define a category must be shared by all organisms placed into that category.)
✓ … group organisms by fundamental characteristics such as cell structure and chemistry. For example, organisms in domain Eukarya are separated from those in the Bacteria and Archaea domains based on whether their cells have a nucleus, the types of molecules found in the cell wall and membrane, and how they go about protein synthesis.
✓ … group organisms based on developmental characteristics and nutritional strategy. For example, organisms in the animal kingdom (Animalia) are separated from those in the plant kingdom (Plantae) because of differences in the early development of these organisms and the fact that plants make their own food by photosynthesis whereas animals ingest their food. (Kingdoms are most useful in domain Eukarya because they’re not well defined for the prokaryotic domains.)
✓ … separate organisms based on key characteristics that define the major groups within the kingdom. For example, within kingdom Plantae, flowering plants (Angiophyta) are in a different phylum than cone-bearing plants (Coniferophyta).
✓ … separate organisms based on key characteristics that define the major groups within the phylum. For example, within phylum Angiophyta, plants that have two seed leaves (dicots, class Magnoliopsida) are in a separate class than plants with one seed leaf (monocots, class Liliopsida).
✓ … separate organisms based on key characteristics that define the major groups within the class. For example, within class Magnoliopsida, nutmeg plants (Magnoliales) are put in a different order than black pepper plants (Piperales) due to differences in their flower and pollen structure.
✓ … separate organisms based on key characteristics that define the major groups within the order. For example, within order Magnoliales, buttercups (Ranunculaceae) are in a different family than roses (Rosaceae) due to differences in their flower structure.
✓ … separate organisms based on key characteristics that define the major groups within the family. For example, within family Rosaceae, roses (Rosa) are in a different genus than cherries (Prunus) thanks to differences in their flower structure.
✓... separate eukaryotic organisms based on whether they can successfully reproduce with each other. You can walk through a rose garden and see many different colors of China roses (Rosa chinensis) that are all considered one species because they can reproduce with each other.
Ex. 39. Find the definitions for the words from the list below. Be ready to interpret the definitions.
More recently, taxonomists divided Monera into Bacteria and Archaea, based on RNA studies. Meanwhile, Fungi was reclassified as a kingdom separate from Plantae (indeed, many experts describe fungal organisms as closer to animals).
Protista, Animalia, Bacteria, Fungi, Archaea, Plantae
1. This kingdom includes multicellular organisms that consume other organisms or organic matter for energy. They also can move independently for at least part of their life cycle, and have thin cell membranes. The kingdom includes, among other species, mammals, birds, insects, reptiles and arthropods.
2. The organisms of this kingdom have chlorophylls a and b and produce energy from sunlight and carbon dioxide. In addition, members of the kingdom have rigid cell walls containing cellulose, and do not move independently. This kingdom include trees, bushes, grasses, ferns and green algae.
3. The organisms of this kingdom, like plants, have rigid cell walls and do not move independently; and like ferns, they reproduce via spores. However, taxonomists eventually distinguished fungi from plants. Like animals, these organisms consume external organic matter for energy, and unlike plants, they have no chlorophyll and no cellulose. Mushrooms, yeasts and molds are members of this kingdom.
4. This kingdom includes organisms of only one cell, or cell colonies that do not form differentiated tissues and whose cells contain distinct nuclei and organelles. Protozoa, red algae, slime molds and water molds belong to this kingdom.
5. Some taxonomists use the name Eubacteria for this kingdom. Others occasionally give this kingdom the old Monera label. This kingdom is composed of single-celled organisms that do not contain distinct nuclei and rarely contain organelles. Bacterial organisms are ubiquitous on Earth, found everywhere from deep-sea hot springs to the human gut.
6. Sometimes called Archaebacteria, ths kingdom comprises single-celled organisms that contain no distinct nuclei or organelles. Although very similar in appearance to bacteria, these organisms have different genetic structures and metabolic processes. The representatives of this kingdom, initially thought to inhabit only extreme environments like sulfur springs, have been found all over the planet and are particularly abundant in plankton.
Ex. 40. Translate the following text into English.
Існує декілька систем організмів. Наведемо приклад однієї з них.
У біології розрізняють неклітинні та клітинні організми. Неклітинні мають лише одне царство — Віруси. (Царство є найвищою одиницею класифікації). Клітинні організми нараховують два надцарства: прокаріоти, або доядерні, та еукаріоти (ядерні). До прокаріотів належить одне царство Дроб’янки (три підцарства: бактерії, архебактерії та ціанобактерії, або синьо-зелені водорості). Друге об’єднує три царства: Тварини (два підцарства: найпростіші, або одноклітинні, та багатоклітинні), Рослини (три підцарства: справжні водорості, багрянкові та вищі рослини) і Гриби (два підцарства: нижчі та вищі гриби).
Увесь світ живого сучасними систематиками найчастіше поділяється на п’ять царств: Віруси, Дроб’янки, Рослини, Гриби, Тварини. Головними таксономічними категоріями є царство, відділ (у тварин — тип), клас, порядок, родина (у тварин — ряд), рід і вид.
