Chapter 2: BiodiversityShort Questions with Answers

Biodiversity: the variety of organisms in a particular area, measured by the number of kinds of organisms and the variation within each kind.

Kingdom, phylum (division), class, order, family, genus and species. (Domain was added above kingdom in 1977.)

Kingdom Animalia. Animals are eukaryotic, multicellular, heterotrophic, have no cell wall, and ingest food.

Archaea, Bacteria and Eukarya.

Viruses are acellular: not made of cells and without organelles; they cannot run metabolism. They lack any of the characteristics of the three domains of life, so they are not included in the classification system.

The scientific name is in Latin (spoken by no country) and is the same anywhere in the world, so a biologist speaking Chinese, Arabic, Spanish or English uses the same name; no two organisms share a name, unlike common names which differ by region.

On May 22nd, as designated by the United Nations, to promote the protection of biodiversity.

Some respect it only because it is useful to humans; others respect biodiversity on aesthetic and moral grounds.

Acellular particles not included in classification: prions are composed of protein only and viroids of circular RNA only. They cause infectious diseases in certain plants.

By respiratory droplets and contaminated surfaces. Prevention: mask, washing hands with soap for 20 seconds or 60% alcohol sanitizer, and vaccination.

Plasmodium causes malaria; Entamoeba causes amoebic dysentery.

The variety of organisms in a particular area. It depends on climate, altitude and soil type; tropical regions have more than polar regions.

About 2 million: about 0.5 million kinds of plants and 1.5 million kinds of animals, a small percentage of the total.

Dividing organisms into groups and subgroups on the basis of similarities and differences. Aims: to study organisms easily and to find their evolutionary relationships.

The groups into which organisms are classified, i.e. taxonomic ranks (singular: taxon).

The lowest level of classification: a group of similar organisms that can interbreed and produce fertile offspring.

Domain, added in 1977 (by Carl Woese).

Eukarya → Animalia → Chordata → Mammalia → Primates → Hominidae → Homo → Homo sapiens.

Both are the same rank below kingdom; "division" is used for plants and fungi, "phylum" for animals and others.

Aristotle (384–322 BC) classified organisms into two groups: plants and animals.

He described the characteristics of 350 species of animals and wrote a lot about the life of ants.

Euglena has both plant-like (chlorophyll) and animal-like (heterotrophic in darkness, no cell wall) characteristics; the system also did not separate prokaryotes from eukaryotes.

Levels of cellular organization (prokaryotic, unicellular eukaryotic, multicellular eukaryotic) and modes of nutrition (photosynthesis, absorption, ingestion).

Monera, Protista, Fungi, Plantae and Animalia.

Carl Woese (1977), based on the differences between Archaea and Bacteria; he split the prokaryotes into two domains.

They are considered the most ancient forms of life; prokaryotes adapted to extreme conditions like those on the early Earth.

Methanogens (produce methane), halophiles (salty places), thermophiles (hot springs), acidophiles (acidic places).

Prokaryotes with peptidoglycan cell walls, found in all environments, unicellular (some in chains or colonies); most heterotrophic, some photosynthetic. Kingdom Eubacteria.

Protista, Fungi, Plantae and Animalia.

Plant-like (algae): Euglena, diatoms; animal-like (protozoa): Amoeba, Paramecium; fungus-like: slime molds, water molds.

Fungus-like protists have cell walls of cellulose; fungi have chitin.

Eukaryotic, multicellular, cellulose cell walls, autotrophic (photosynthesis), multicellular sex organs, form embryos.

Animals ingest food and digest it inside the body; fungi absorb food from decaying matter.

Making bread, cheese and beer; the antibiotic penicillin from Penicillium.

Outside a host they are inert particles that cannot run metabolism; inside a host cell they reproduce, which is a sign of life.

Nucleic acid (DNA or RNA) surrounded by a protein coat.

A virus which attacks bacteria.

The system of scientific naming in which each name has two parts, genus and species. Carl Linnaeus founded it.

Latin is spoken by no country, so no country is favoured and the name is the same everywhere.

They vary by region (onion: piyaz, ganda, bassal), one name may mean several organisms (black bird), and they have no scientific basis (jellyfish is not a fish).

Allium cepa, Solanum tuberosum, Panthera tigris.

Genus with a capital letter, species with a small letter, and the two parts underlined separately.