🔬 Taxonomía 🦠🍄 Clasificación de los Seres Vivos 🌿🐶Explicación, ejemplos + Quiz 📚🧬STEM. Biología

Introduction to Taxonomy

Overview of Taxonomy

• The video introduces taxonomy, a branch of biology focused on the systematic classification of organisms in an ordered and hierarchical manner.

• It emphasizes that taxonomy not only names living beings but also helps understand their evolutionary and ecological relationships.

Historical Context

• Carl Linnaeus, a 17th-century Swedish naturalist, was the first scientist to attempt classifying living beings using a hierarchical system still in use today.

• Linnaeus's classification levels include kingdom, phylum (or division), class, order, family, genus, and species.

Classification Levels Explained

Human Classification Example

• Humans are classified as follows:

• Kingdom: Animalia (multicellular and heterotrophic)

• Phylum: Chordata (vertebrates)

• Class: Mammalia (warm-blooded with mammary glands)

• Order: Primates

• Family: Hominidae

• Genus: Homo

• Species: Homo sapiens

Five Kingdom Classification by Robert Whittaker

• In 1969, biologist Robert Whittaker proposed a more detailed classification dividing life into five kingdoms based on cell type, nutrition form, and cell number.

The Five Kingdoms:

1. Monera

• Organisms are prokaryotic; examples include bacteria like Escherichia coli.

• Reproduction is mostly asexual through binary fission.

• Nutrition can be autotrophic or heterotrophic.

2. Protista

• Eukaryotic organisms that can be unicellular or colonial; example includes Amoeba proteus.

• Nutrition varies between autotrophic and heterotrophic.

3. Fungi

• Includes fungi and yeasts; they are eukaryotic and heterotrophic.

• Reproduction can be asexual via spores or budding or sexual through cell fusion.

4. Plantae

• Multicellular eukaryotes that are autotrophic through photosynthesis; example is Quercus robur (oak tree).

• Reproduction occurs sexually via seeds/spores or asexually via cuttings/rhizomes.

5. Animalia

• Multicellular eukaryotes that are heterotrophs; reproduction is primarily sexual with some exceptions for invertebrates.

• Example includes dolphins which are intelligent marine mammals.

Three Domains of Life

Carl Woese's Proposal

• In 1977, microbiologist Carl Woese introduced a new classification based on ribosomal DNA leading to three domains:

The Three Domains:

1. Bacteria

• Comprises common bacteria which are prokaryotic with peptidoglycan cell walls.

2. Archaea

• Contains prokaryotic organisms with unique biochemical differences in their membranes; often found in extreme environments like hydrothermal vents.

3. Eukarya

• Encompasses all eukaryotic organisms including animals, plants, fungi, and protists.

Quiz Questions on Taxonomy

Understanding Classification Through Questions

• Quiz questions help reinforce understanding of taxonomy concepts:

• How many kingdoms exist in traditional classification? Answer: Five (Animalia, Plantae, Fungi, Protista, Monera).

• To which domain do humans belong? Answer: Eukarya.

• What kingdom does the dog belong to? Answer: Animalia.

• Which domain includes unicellular organisms without defined nuclei? Answer: Archaea & Bacteria.

• What defines the Fungi kingdom? Answer: They absorb nutrients from their environment as heterotrophs.