https://padlet.com/duaijalqallaf/7slbm25qkyhi animal diversity, history of life en-us 2016-12-07 06:51:07 UTC 2025-10-02 18:24:55 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Rafaelo.png duaijalqallaf https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142207965 2016-12-07 06:56:17 UTC https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142207965 duaijalqallaf https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142208021 Nutritional Mode: Animals get organic molecules through eating other living organisms or by eating nonliving organic material.

Cell Structure and Specialization: Animals lack the structural support of cell walls, so instead they have a number of proteins that aid in the strengthening of the cell membrane like collagen. Some cells in animals are specialized, like muscle cells and nerve cells, that form tissues which are a group of cells that have common structures and/or functions.

Reproduction and Development: 

• cleavage: a succession of mitotic cell divisions without cell growth between the divisions
• Blastula: forms after cleavage and is a multicellular stage which in many animals forms as a hollow ball
• Gastrulation: the layers of embryonic tissues that will develop into adult body parts are produced at this stage. Then a Gastrula forms.
• Larva: sexually immature of an animal that can be very different from how the adult looks and acts
• Metamorphosis: a developmental transformation that turns the animal into a juvenile that resembles an adult but is not yet sexually mature

]]> 2016-12-07 06:57:03 UTC https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142208021 alinahar https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142208810 Studies suggest that the ancestors of animals diverged from the ancestors of fungi about a billion years ago and that the common ancestor of living animals lived sometime between 800 and 675 million years ago.

Neoproterozoic Era (1 billion-542 million years ago): The first generally accepted macroscopic fossils of animals date from 565 to 550 million years ago, these early fossils are members of the early group Ediacaran biota. Many of the fossils found have been difficult to classify because they do not seem to be related do any living groups.

Paleozoic Era (542-251 million years ago): A phenomenon during the Cambrian period known as the Cambrian explosion occurred when a wave of animal diversification came by. These include the first arthropods, chordates, and echinoderms. With the increase in the diversity of animals during the Cambrian, a decline in the diversity of Ediacarans was seen. After the Cambrian period came the Ordovician, Silurian, and Devonian periods when animal diversities continued to increase, however followed by episodes of mass extinction. Vertebrates made the transition to land around 365 million years ago. Two of these groups survive today: amphibians (frogs and salamanders) and amniotes (reptiles, birds, mammals)

Mesozoic Era (251-65.6 million years ago): During this period the first coral reefs formed, providing marine animals with new habitats. Some reptiles returned to the water. Dinosaurs emerged, both predators and herbivores, along with the first mammals.

Cenozoic Era (65.5 million years ago to the present): Mass extinction formed a new era. Nonflying dinosaurs and marine reptiles disappeared. The climate gradually cooled in this era. The ancestors of our species were among the grassland apes.]]> 2016-12-07 07:08:55 UTC https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142208810 duaijalqallaf https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142210940 A body plan is a particular set of morphological and developmental traits, integrated into a functional whole which is the living animal itself.

Plans provide a succinct way to compare and contrast key animal features and are a way of studying the interface between evolution and development. Body plans also evolved over time and some of the changes appear to have occurred early on in the history of animal life; like the unchanged key step in molecular control of gastrulation that remained for 500 million years. Bodily changes can also occur over time like the loss of organs or the gaining of organs causing some closely related species to look very different from one another.

Symmetry

• Radial Symmetry: The animal has a top side and a bottom side, but no front or back sides nor a right and left sides.
• Bilateral Symmetry: Front and back, top and bottom.
• Dorsal: top
• Ventral: back
• Anterior: front
• posterior: back
• Cephalization: A central nervous system in the head

Tissues

• Ectoderm: germ layer covering the surface of the embryo and gives rise to the outer covering of the animal and sometimes to the central nervous system
• Endoderm: the innermost germ layer, lines the pouch that forms during gastrulation and gives rise to the lining of the digestive track
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]]> 2016-12-07 07:26:56 UTC https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142210940 alinahar https://padlet.com/duaijalqallaf/7slbm25qkyhi/wish/142213778 Biologists nowadays reconstruct phylogenies using molecular data, along with the use of fossil data and cladistics.
 
Points of Agreement

• All animals share a common ancestor
• Sponges are basal animals
• Eumetazoa is a clade of animals with true tissues
• Most animal phyla belong to the clade BIlateria

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