Cell Division Stages and Biological Kingdom Characteristics

Meiosis I

Prophase I

In Prophase I, homologous chromosomes synapse to form tetrads, and crossing over occurs in the chiasmata. The nuclear envelope degrades.

Metaphase I

During Metaphase I, homologous chromosomes in tetrads are aligned in the equatorial plane of the cell and held together at the chiasmata (the prior crossover sites).

Anaphase I

In Anaphase I, homologous chromosomes separate and move to opposite poles. The sister chromatids remain attached at their centromeres.

Telophase I

In Telophase I, the chromatids decondense, nuclear envelope reorganization occurs, and cytokinesis takes place.

Meiosis II

Prophase II

In Prophase II, in each of the two cells that formed at the end of Meiosis I, the chromosomes condense again.

Metaphase II

During Metaphase II, chromosomes are aligned along the equatorial plane of each cell.

Anaphase II

In Anaphase II, the sister chromatids separate at their centromeres, and the chromosomes move to opposite poles.

Telophase II

In Telophase II, nuclei are formed at opposite ends of each cell and cytokinesis occurs.

The Five Kingdoms of Life

Kingdom Monera

• Comprises prokaryotic organisms.
• They live singly or in colonies.
• They have cell walls (some have peptidoglycan and others do not).
• Locomotion is by flagella or they are immobile; they utilize anaerobic respiration.
• They feed by absorption, photosynthesis, and chemosynthesis.
• Asexual reproduction occurs via binary fission and by conjugation.

Kingdom Protista

• Consists of eukaryotic organisms.
• Unicellular or colonial.
• Utilize aerobic respiration.
• Locomotion by flagella and cilia.
• Nutrition through absorption, ingestion, and photosynthesis.
• Engage in some asexual and sexual reproduction with gametes and zygotes.

Kingdom Fungi

• Eukaryotic organisms.
• Multicellular; they form a mycelium (a set of hyphae).
• Nutrition by absorption.
• Utilize aerobic respiration.
• Engage in sexual and asexual reproduction.
• Cell walls contain chitin.

Kingdom Plantae

• Eukaryotic organisms.
• Nutrition through photosynthesis.
• Multicellular autotrophs that are motionless.
• Utilize aerobic respiration.
• Engage in asexual and sexual reproduction.
• They have cell walls with cellulose.

Kingdom Animalia

• Multicellular eukaryotes.
• Engage in some asexual and sexual reproduction.
• They are heterotrophs.
• They present tissues, organs, and systems.
• Some have a coelom and a well-defined nervous system.
• Mechanisms of locomotion are mostly well-developed.