Identify traits that characterize all animals.

Question

State one way that animal cells differ from the cells of plants and fungi. What is the significance of this difference?
Describe animal digestion.
Describe a general animal life cycle.
State how the phylum Chordata differs from other animal phyla.
Compare and contrast invertebrates and vertebrates.

Answer 1

Traits that Characterize All Animals

1. Multicellularity: Animals are multicellular organisms, composed of diverse cell types that work together.
2. Heterotrophy: Animals cannot produce their own food; instead, they obtain nutrition by consuming organic material.
3. Highly Specialized Cells: Animal cells are specialized for various functions, with structures like muscle cells for movement and nerve cells for signaling.
4. Movement: Most animals have the ability to move at some stage of their life cycle, usually powered by muscle tissue.
5. Reproduction: Animals primarily reproduce sexually, but many can also reproduce asexually. Most animals have distinct life stages.
6. Nervous System: Most animals possess a nervous system that enables them to respond quickly to environmental stimuli, although the complexity can vary greatly.

One Way Animal Cells Differ from Plant and Fungi Cells

Animal cells do not have a cell wall, whereas plant cells and fungal cells do. Plants have a rigid cell wall made of cellulose, while fungi have cell walls made of chitin. The significance of this difference lies in the flexibility and mobility of animal cells; without a rigid cell wall, animal cells can change shape, allowing for the formation of various structures such as muscles and the nervous system.

Animal Digestion

Animal digestion typically occurs in a specialized digestive tract, where food intake and nutrient absorption are broken down through mechanical and chemical processes. The process generally involves:

1. Ingestion: The intake of food through the mouth.
2. Digestion: Mechanical (chewing) and chemical (enzymes) processes that break down food into smaller molecules.
3. Absorption: Nutrient molecules are absorbed through the intestinal wall into the bloodstream.
4. Egestion: The elimination of undigested food material as waste.

General Animal Life Cycle

The life cycle of an animal typically includes several key stages:

1. Fertilization: The union of male and female gametes, leading to the formation of a zygote.
2. Embryonic Development: The zygote undergoes cell division and differentiation to develop into a multicellular embryo.
3. Juvenile Stage: The young organism, which may resemble adults but often is smaller and not yet mature (e.g., tadpoles).
4. Adult Stage: The mature organism that can reproduce.
5. Reproduction: The cycle continues with the production of gametes.

Difference of Phylum Chordata from Other Animal Phyla

The phylum Chordata is characterized by the presence of a notochord (a flexible rod-like structure), a dorsal nerve cord, pharyngeal slits, and post-anal tail at some stage of development. These features set chordates apart from other phyla, which may lack these structures or have different morphologies.

Compare and Contrast Invertebrates and Vertebrates

Similarities:

• Both invertebrates and vertebrates are part of the animal kingdom and exhibit multicellularity and heterotrophy.
• Both groups can reproduce sexually and asexually.

Differences:

• Vertebrates: These animals possess a backbone or vertebral column (spine). They usually have a complex internal skeleton, a more centralized nervous system, and organized organ systems (e.g., respiratory, circulatory).
• Invertebrates: This group lacks a backbone. Invertebrates exhibit a wide range of body plans and can include organisms like arthropods, mollusks, and cnidarians. They may have simpler nervous systems and less complex organ systems compared to vertebrates.

In summary, while invertebrates and vertebrates share core animal traits, their structural and functional complexities differ significantly, primarily due to the presence or absence of a vertebral column.