Animal Form, Function, and Evolutionary History

What is the core concept regarding animal body plans?

Animals have a limited number of body plans.

How many types of tissues do most animals have?

Four different types of tissues.

What is homeostasis in animals?

Homeostasis actively maintains a stable internal environment.

When did animals evolve?

Animals evolved more than 600 million years ago in the oceans.

What major evolutionary milestone occurred by 500 million years ago?

The major body plans were in place.

What stage dominates the life cycle of animals?

The diploid stage.

How are haploid gametes produced in animals?

Haploid gametes are made by meiosis.

What are the methods of asexual reproduction in animals?

Binary fission, budding, fragmentation, and parthenogenesis.

What is the difference between external and internal fertilization?

External fertilization has a higher chance of failure due to environmental needs of sperm and egg.

What is cephalization?

Cephalization is the concentration of sensory organs and nervous tissue at the anterior end of an organism.

What is segmentation in bilaterians?

Segmentation refers to the division of the body into repetitive segments.

What is a coelom?

A coelom is a fluid-filled body cavity that cushions internal organs.

What is the function of the amnion in embryonic development?

The amnion surrounds a fluid-filled cavity that allows the embryo to develop in a watery environment.

What significant evolutionary event occurred during the Cambrian period?

The body plans characteristic of most bilaterian phyla took shape during the Cambrian explosion.

What are Ediacaran fossils known for?

Ediacaran fossils are simple shapes, many flat, with no obvious head or tail.

What major event occurred at the end of the Permian period?

Mass extinctions wiped out most genera living in oceans.

What is the significance of the Cambrian explosion?

It was a relatively short time with a huge accumulation of new characters in animal evolution.

What role do genetic codes play in animal development?

Development is regulated by distinctive bits of genetic code shared across the entire group of Eukarya.

What is the relationship between cell changes and animal development?

Development involves changes in cell form, cell-cell interactions, and cell position.

What is the significance of the transition period during the Cambrian?

It marked a rapid appearance of diverse animal forms and structures.

What is parthenogenesis?

Parthenogenesis is a form of asexual reproduction where an egg develops into an organism without fertilization.

What adaptations are associated with internal fertilization?

Internal fertilization is generally seen as an adaptation for being terrestrial.