What are animals and how was they related to other forms of life?

homoplasies:

Traits that rised from convergent evolution.

Draw a phylogenetic tree the different catogories of animals and add charecters.

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What are Lophotrochozoans and examples? (3)

Anmals that have a crown of ciliated tentacles for feeding. Bilateral. One example would be Platyhelminthes. Ex: Tapeworms. They are acoelomates. They lack a body cavity. Another example would be Molluscs Body cavity.. Soft body. They have body cavity and a circulation system. Ex: Slugs, squids, snails. 3rd example would be Annelids. "little rings" Body cavity Segmented worms that live in the sea. Soft body. Britsles called chitin. Examples: leeches.

What are desterostomes and what are examples of desterostomes? (2)

Bilateral. Desterostomes have a deutertomes mode of development. Both have a body cavity. Example would be: Chordates: Segmentated Notochord 90% of chordates are vertabrates. but two groups are invertabrates. (Lanceletes and Turnicates) Another examples: Humans Echindermata: these are slowing moving or sessil animals. They have bilateral symmentry as larve. Radial as adults. Ex: sea stars.

What are ecdysozoans and examples? (2)

Bilateral. Ecdysozoans are animals with tough external coat. All animals under this phylum have a body cavity. Example: Nematodes: Worms with tough cuticles as it grows. Body cavity but psedocolemate Ex: roundworms Antropoda: Segmentated Body cavity Mostly insects. Developed sensory organs. Open circulatory system.

Describe the what a body cavity is and it's function. Also describe the different types of animals with body cavities.

Body cavity: a fluid or air filled space located between the digestive tract and the outer body wall. Functions of a body cavity: Its fluids cushions the suspended organs, helping to prevent injury. The cavity also enables the internal organs to grow and move independently of the outer body wall. Different types of body cavities withen animals: Coelomates: Animals with a true coelom. A true coelom: the inner and outer layers of tissue that surround the cavity connect and form structures that suspend the internal organs. Pseudocoelmates: animals that have a body cavity that is formed from the mesoderm and the endoderm. Acoelomates: lack a body cavity all together.

Describe the different tissue layers found in animals.

Ectorderm: the germ layer covering the surface of the embryo that gives rises to the outer covering of the animal and in some phyla to the central nervous system. Endoderm: The innermost germ layer. Give rises to the lignin of the digestive tract and organs of such as the liver and lungs of vertebrates. Animals that have only these 2 tissue layers are diplobastic. All bilateral symmetry have the mesoderm: this fills most of the space between the ectoderm and the endoderm. So animals that are bilateral are called Triploblastic.

What are Cnidaria?

Ex: Sea Anemones and Free Swimming jellies. Radial body plan. Diblostic. Have True Tissue. No brain and no centralized nervous system. Nerves are distributed around the body.

Describe the different types of symmetry found in animals.

Radial symmetry: the type of symmetry in which any imaginary slice through the central axis divides the animal into mirror images. Animals with this symmetry equips them to meet the environment equally well from all of it's sides. Bilateral symmetry: two-sided symmetry. Only one imaginary cut divides the animal into mirror-image halves. Two types of orientation: front to back, and top and bottom. Many animals that have bilateral symmetry have sensory equipment concentrated at their anterior (front) end and a central nervous system in their head. Animals such as these actively move from place to place.

Describe segmentation. Advantages? Disadvantages?

Segmentation in biology refers to the division of some animal and plant body plans into a series of repetitive segments. Found in Annelid, Anthropoda, Chordata.

1. List the shared derived traits (synamorphies) and shared ancestral (symplesiomorphies/homoplasies) traits of animals. (5 for each)

Symplesimorphies or Homoplasis: Eukaryotes Heterotrophic Locomotion Muticellular Internal Digestion Synapomorphies Cell-Cell Junction Extracelluar Matrix Blastula Hox Gene Electrically Excitable Cells

5. Explain the colonial flagellate hypothesis of metazoan origin and why it is currently favored.

The colonial flagellate hypothesis claims that the first animals evolved from flagellated protists that lived in colonies. Many modern flagellates live in colonies, so that provides some support for the hypothesis. According to this hypothesis, as colonial cells became more and more interdependent, some of the cells specialized to perform different tasks, and the cells of the colony became differentiated. Eventually, cells in the colony became so specialized and interdependent that they could not survive on their own. At this point, they would no longer be a colony of cells but a multicellular organism - a simple animal. One of these very early animals would have been quite simple by modern standards, resembling the blastula of a modern animal. Over time, as cells became more specialized and interdependent, early animals would form more complex bodies resembling the gastrulae of modern animals. As cells became ever more specialized and differentiated, true animals evolved as cells formed tissues and then organs.

What are porifera?

They are known as sponges. They don't have true tissue.

Describe early embryotic development. (A small summary)

When sperm reaches the egg of it's mate it undergoes cleavage. Cleavage: a succession of mitotic cell divisions without cell growth between divisions. Cleavage then leads to the formation of a multicellular stage, a blastula. Blastula: a hollow ball of cells. After the blastula stage, Gastrulation happens. Gastrulation: the layers of embryonic tissues that will develop into adult parts are produced. This is the gastrula stage. Most animals include aleast one larval stage. Larva: sexually immature form of an animals that is morphologically distinct from the adult. Eats different food and maybe a different habitat. Larva eventually undergoes metamorphosis. This is the developmental transformation that turns the animal into a juvenile that resembles the adult but that isn't sexually mature.

What are Hox Genes?

are a group of related genes that control the body plan of an embryo along the anterior-posterior (head-tail) axis.

synplesiomorphies?

primative ancestoral traits by a group of organisms but don't show a relationship. A shared trait from the earliest common ancestor.

synapomorphies?

shared traited present two more taxa and in the most recent common ancestor, but not in common ancestor's ancestor.

anceteral trait:

trait orginally found in the ancestor

derived trait:

traits the are present in the present organism but not's ancestor.