Animal Body Plans and Morphology

These flashcards cover key vocabulary terms and definitions related to animal body plans and morphology.

Eukaryotic

Organisms whose cells contain a nucleus and organelles enclosed within membranes.

Metazoans

Another term for animals, referring to multicellular organisms.

Tissue

A group of cells that work together to perform a specific function.

Epithelial Tissue

Tissue that covers body surfaces and lines cavities.

Symmetry

The balanced and proportionate arrangement of body parts.

Radial Symmetry

A body plan in which body parts extend from a central point.

Bilateral Symmetry

A body plan in which the left and right sides of the organism are mirror images.

Germ Layers

The three layers of cells (ectoderm, mesoderm, endoderm) in the developing embryo.

Coelom

A fluid-filled body cavity completely lined with mesoderm.

Acoelomate

An organism that lacks a coelom.

Pseudocoelom

A body cavity that is only partially lined with mesoderm.

Blastula

An early stage of embryonic development that forms a hollow ball of cells.

Protostomes

Animals in which the blastopore develops into the mouth.

Deuterostomes

Animals in which the blastopore becomes the anus.

Cephalization

The concentration of sensory organs and nerve cells at the front end of the body.

Limb Formation

The development of appendages such as legs, flippers, and wings.

Cladogram

A branching diagram showing evolutionary relationships among species.

Epithelial Tissue Types

Classified based on cell shape and the number of layers.

Regeneration

The ability of an organism to re-grow lost parts.

Gemmules

Asexual structures formed by sponges that can survive harsh conditions.

Hydrozoa

A class of Cnidarians that includes hydras and Portuguese man-of-war.

Nematocysts

Specialized stinging structures in Cnidarians used for defense and prey capture.

Cnidocytes

Cells in Cnidarians that contain nematocysts.

Sponges

Simple aquatic animals that belong to the phylum Porifera, characterized by a porous body and the absence of true tissues and organs. Sponges play a crucial role in aquatic ecosystems as filter feeders, helping to maintain water clarity and quality.

Porifera

The phylum to which all sponges belong. It is characterized by their porous bodies and the presence of specialized cells called choanocytes that aid in the filtration of water.

Choanocytes

Specialized cells in sponges that have flagella and create water currents to draw water through the sponge's body, facilitating feeding, respiration, and excretion.

Body Plan of Sponges

Sponges have a unique body plan consisting of a body wall with three layers: the outer pinacoderm, the inner choanoderm, and the mesohyl in between, which contains skeletal elements and other cells. This structure is important for their filter-feeding mechanism.

Reproduction in Sponges

Sponges can reproduce both sexually and asexually. Asexual reproduction occurs through budding or the formation of gemmules, while sexual reproduction involves the production of sperm and eggs, leading to the formation of larvae.

Cnidarians

A diverse group of animals belonging to the phylum Cnidaria, including jellyfish, corals, and sea anemones. Cnidarians are known for their radial symmetry and the presence of specialized cells called cnidocytes which contain nematocysts.

Cnidocytes and Nematocysts

Cnidocytes are specialized stinging cells in Cnidarians that contain nematocysts, which are used for capturing prey and defense. Understanding these cells is important for appreciating the ecological roles of Cnidarians.

Body Plan of Cnidarians

Cnidarians have a simple body plan with two main forms: polyp (sessile) and medusa (free-swimming). This versatile body plan allows them to occupy different ecological niches.

Corals

A type of Cnidarian that forms large colonies made up of individual polyps. Corals play a crucial role in building coral reefs, which serve as important marine habitats and protect coastlines.

Sea Anemones

Sessile Cnidarians that resemble flowers and are often found attached to rocks or coral. They have stinging tentacles for capturing prey and can form symbiotic relationships with clownfish.

Jellyfish

Medusa-form Cnidarians that drift through the water and can have long tentacles equipped with nematocysts. Jellyfish are important components of marine food webs and can sometimes have harmful effects on human activities.

Ecological Importance of Sponges

Sponges contribute to nutrient cycling in oceans and help improve water quality by filtering out bacteria, particulate matter, and toxins.

Ecological Importance of Cnidarians

Cnidarians, such as corals, contribute to the structure of marine ecosystems by providing habitat for other marine organisms. They also play a role in nutrient cycling and are indicators of environmental health.

Symbiosis in Cnidarians

Many Cnidarians engage in symbiotic relationships with algae (zooxanthellae) that live within their tissues. This relationship is crucial for coral health, as the algae provide nutrients through photosynthesis.

Ctenophores

Also known as comb jellies, ctenophores are a phylum of marine invertebrates characterized by their gelatinous bodies and the presence of eight rows of ciliary plates called ctenes used for locomotion.

Body Structure of Ctenophores

Ctenophores have a soft, transparent body and can be either spherical or elongated. They exhibit a simple body structure that includes a mouth, two anal pores, and specialized cells called colloblasts that help capture prey.

Ctenes

Ctenes are the comb-like structures composed of cilia that line the body of ctenophores. These structures enable them to move gracefully through the water and are responsible for their characteristic shimmering appearance.

Feeding Mechanism of Ctenophores

Ctenophores are primarily carnivorous and use their colloblasts to capture small prey such as zooplankton. They funnel the captured prey into their mouth, demonstrating a unique feeding strategy among gelatinous organisms.

Reproduction in Ctenophores

Ctenophores can reproduce asexually through budding or sexually by spawning, where eggs and sperm are released into the water. Fertilization occurs externally, and the resulting larvae develop into free-swimming ctenophores.

Ecological Role of Ctenophores

Ctenophores play a significant role in marine ecosystems as both predators and prey. They are important in controlling zooplankton populations and serving as food for larger marine organisms like fish.

Bioluminescence in Ctenophores

Many ctenophores exhibit bioluminescence, producing light when disturbed. This phenomenon can attract prey or deter predators, highlighting their adaptive significance in the marine environment.

Importance of Ctenophores in Marine Research

Studying ctenophores is vital for understanding marine biodiversity and ecosystem dynamics. Their unique characteristics and behaviors can provide insights into evolutionary biology and the health of marine

Animal Hierarchy of Development

A structured progression of complexity in embryonic development across various animal groups.

Zygote

The fertilized egg that results from the union of sperm and egg, marking the beginning of development.

Cleavage Stage

The series of rapid cell divisions that the zygote undergoes, leading to the formation of a multicellular structure called a blastula.

Blastula

A hollow ball of cells formed during early embryonic development, which eventually gives rise to the germ layers.

Gastrulation

The process by which the blastula reorganizes into a three-layered structure, forming the ectoderm, mesoderm, and endoderm.

Ectoderm Layer

The outermost germ layer that develops into the skin, nervous system, and other external features.

Mesoderm Layer

The middle germ layer that forms muscles, bones, and internal organs.

Endoderm Layer

The innermost germ layer that develops into the lining of the digestive tract and other internal organs.

Organogenesis

The phase of development where organ systems begin to form from the three germ layers, leading to the establishment of functional structures.

Differentiation

The process by which unspecialized cells become specialized in structure and function to form specific tissues and organs.

Morphogenesis

The biological process that causes an organism to develop its shape, involving cell division, growth, and spatial arrangement.

Developmental Stages

Refers to the distinct phases of development, including embryonic, larval, and adult stages, that occur in various organisms.

Fate Mapping

A method used to trace the developmental lineage of specific cells to understand how particular structures arise from embryonic cells.

Evolutionary Significance

Understanding animal hierarchy of development provides insights into evolutionary adaptations and the relationships among diverse species.

Real-life Application

Knowledge of animal development is essential in fields such as medicine, conservation, and biotechnology, where understanding growth and disease mechanisms can have practical benefits.

Asconoid Sponges

The simplest type of sponge, characterized by a tubular body structure with a central cavity called the spongocoel, and choanocytes lining its walls.

Syconoid Sponges

A more complex type of sponge with thicker walls and radial canals that increase the surface area for filtering water.

Leuconoid Sponges

The most complex type of sponge, featuring a highly branched body structure with many small chambers that increase the efficiency of water filtration.

Characteristics of Sponges

Sponges can be classified based on their body structure (asconoid, syconoid, leuconoid) and exhibit features such as porosity, choanocytes for filtering, and a lack of true tissues.

Class Calcarea

This class of sponges is characterized by their calcium carbonate spicules. They are typically small and can have various body forms such as asconoid, syconoid, or leuconoid.

Class Hexactinellida

Also known as glass sponges, this class is distinguished by their siliceous spicules, which are often six-rayed. They have a unique structure and are typically found in deep ocean environments.

Class Demospongiae

The largest class of sponges, comprising around 90% of all sponge species. They have siliceous spicules that are not six-rayed and can be found in various habitats, from freshwater to deep sea.

Class Homoscleromorpha

This class includes sponges that have a unique cellular structure and can show characteristics of both sponges and more complex organisms. They typically have a simple body plan and a reduced skeleton.