BSC2011 Study Guide: Animals and Evolution

A series of flashcards summarizing key terms and concepts from BSC2011 Unit 2 on animals and their evolution.

Body Symmetry

The arrangement of body parts in relation to a central point, including asymmetrical, radial, and bilateral symmetry.

Asymmetrical

A type of body symmetry where there is no plane of symmetry, as seen in sponges.

Radial Symmetry

Body parts are arranged around a central axis, found in organisms like Cnidarians.

Bilateral Symmetry

Body can be divided into mirror-image halves along one plane, characterized by distinct dorsal, ventral, anterior, and posterior regions.

Body Cavities

The fluid-filled spaces inside bodies formed from three embryonic cell layers: ectoderm, endoderm, and mesoderm.

Acoelomate

An organism with no body cavity, relying on diffusion for internal transport, e.g., flatworms.

Pseudocoelomate

An organism with a fluid-filled cavity that is not completely lined by mesoderm, allowing some organ suspension, e.g., roundworms.

Coelomate

An organism with a true coelom, leading to more complex organ systems and specialized movement.

Segmentation

The division of body into repetitive segments, allowing for more specialized movement and body control.

Appendages

Structures that enhance an animal's movement and include various limbs and feeding instruments.

Nervous System

The system that coordinates muscle action and processes sensory information, which can be diffuse, like in Cnidarians, or centralized, like in bilaterians.

Protostomes

A major group of bilateral animals whose mouth develops from the blastopore.

Deuterostomes

A major group of bilateral animals whose anus develops from the blastopore.

Echinoderms

Marine animals with radial symmetry as adults and bilateral symmetry in larvae, possessing unique water vascular systems.

Chordates

Animals characterized by dorsal hollow nerve cords, post-anal tails, notochords, and pharyngeal slits.

Homeostasis

The maintenance of stable internal conditions within the body despite changes in the external environment.

Endotherms

Warm-blooded animals that maintain a constant body temperature through metabolic activity.

Ectotherms

Cold-blooded animals whose body temperature is regulated by the external environment.

Innate Behavior

Instinctual actions present at birth that are not learned through experience.

Learning

Behavioral modification based on past experience, improving survival in changing environments.

Fixed Action Patterns

Highly stereotyped behaviors that are triggered by specific stimuli and do not require learning.

Epigenetic Tagging

The process by which early life experiences can modify gene expression without changing the DNA sequence.

Adaptation

A trait that increases an organism's fitness in a specific environment, often shaped by natural selection.