Unit 13: Intro to Animal Diversity and Development

What are animals?

Animals are multicellular, eukaryotic, ingestive heterotrophs

How do animals feed?

Animals feed by ingesting food and using enzymes within their bodies to digest it

What do animals have instead of a cell wall?

An extracellular matrix

What is the extracellular matrix made of?

Membrane proteins, collagen, and fibers

What is the purpose of the extracellular matrix?

To provide structural support

What are the three purposes of collagen?

1) Makes cells flexible 2) Supports cell shape 3) Helps cells adhere to one another

Where is collagen found?

Cartilage, ligaments, bones, tendons, skin, etc

What tissues are unique to animals?

Muscle tissue and nerves

What is the purpose of muscle tissue?

Moves body

What is the purpose of nervous tissue?

Conduct nerve impulses - neurons receive and transmit impulses

When did animals evolve?

~700 Million Years Ago, about 1 Billion years after the first eukaryotes

What era were the oldest animal fossils found?

Ediacaran era, ~560 MYA

What are the characteristics of animals from the Ediacaran era?

Soft-bodied, radial symmetry including mollusks, sponges, cnidarians

When was the Cambrian Explosion?

~540 MYA

Where were animals during the Cambrian Explosion?

Still in the ocean

What happened during the Cambrian Explosion?

Rapid evolution, increase in oxygen allowed larger body sizes, predation; origin of all modern animal phyla

When did animals move onto land?

~450 MYA

What group was the first to move onto land?

Arthropods (millipedes, centipedes, spiders)

When did vertebrates colonize land?

~365 MYA

What characteristics can distinguish different groups of animals?

Symmetry, # of Germ Layers, and Type of Embryonic Development

What are the three major animal clades?

Metazoa, Eumetazoa, and Bilateria

What groups are included in Metazoa?

Phylum Porifera and Clade Eumetazoa

What are the characteristics of Phylum Porifera?

Sponges; lack symmetry and tissues

What groups are included in Eumetazoa?

Phylum Ctenophora, Phylum Cnidaria, and Bilateria

What are the characteristics of Eumetazoa?

True tissues

What are the characteristics of Cnidarians?

Radial symmetry and diploblastic

What is radial symmetry?

Front/back and left/right are symmetrical, but top/bottom is not

What are the characteristics of radially symmetrical animals?

Sessile organisms, move slowly, meet environment from all sides

What is included in clade Bilateria?

Most animals belong to Bilateria

What the general characteristics of Bilateria?

Bilateral Symmetry and Triploblastic

What is bilateral symmetry?

Have two axes of orientation, left/right are symmetrical but top/bottom and front/back are not

Define anterior

Front (head)

Define posterior

Back (anus)

Define dorsal

Top

Define ventral

Bottom

How do animals in Bilateria move?

Animals actively move place to place

What the stages of animal embryonic development?

Zygote - Cleavage - Blastula - Gastrulation

What is a zygote?

Diploid cell created by fertilization - fusing of two haploid gametes

What is cleavage?

Repeated divisions without growth

What is a blastula?

Multicellular hollow ball of cells - hollow center is a Blastocoel

What is gastrulation?

One end of the embryo folds inward

What are the general stages of animal development/sexual reproduction?

1) Haploid gametes fuse (fertilization) to produce a diploid zygote 2) Zygote undergoes mitosis to produce a diploid multicellular organism 3) Organism's sex cells undergo meiosis to produce haploid gametes

What stage is dominant in animal development?

Diploid

Describe fertilization in animals?

Small flagellated sperm swims to a larger nonmotile egg and fuse to create a zygote, starting DNA synthesis

What happens during cleavage?

Repeated mitotic divisions without growth, the cell duplicates DNA and divides repeatedly, cells get smaller and smaller

What is determinate cleavage?

Fate of early embryonic cell is determined - removing a cell causes the embryo to be missing key parts

What is indeterminate cleavage?

Each early embryonic cell retains capacity to develop into complete embryo

How many cleavage divisions produce a blastula?

5-7

What is the embryo called during Gastrulation?

Gastrula

What are the parts of a Gastrula?

Ectoderm, Blastocoel, Endoderm, Archenteron, and Blastospore

What is the opening of the Gastrula called?

Blastospore

What is the cavity of the Gastrula called?

Archenteron

What is the purpose of Gastrulation?

1) Makes digestive tube 2) Creates 2-3 "germ" (embryonic tissue) layers

What are the two primary digestive systems produced by Gastrulation?

Gastrovascular Cavity and Complete Digestive Tract

What is a Gastrovascular cavity?

One opening (blastospore) is both mouth and anus

How does a Gastrovascular cavity form?

Archenteron pushes inward but stops

What is a Complete Digestive Tract?

Two separate openings for mouth and anus

How does a Complete Digestive Tract form?

Archenteron grows through to other side completely, forms a tube

What are the three embryonic tissue layers?

Ectoderm, Mesoderm, and Endoderm

What layers do Diploblasts have?

Ectoderm and Endoderm

What layers do Triploblasts have?

Ectoderm, Mesoderm, and Endoderm

What is the ectoderm?

The outer layer, becomes the epidermis and central nervous system

What is the mesoderm?

Middle layer, becomes muscles and most organs not part of digestive tract

What is the endoderm?

Inner layer, becomes digestive tracts and some organs (lung, liver)

What groups are Diploplastic?

Phyla Cnidaria and Ctenophora (Porifera are neither, they have no tissue!)

What is the development of embryonic layers for Diploblastic animals?

Endoderm becomes Gastrovascular Cavity and Ectoderm becomes epidermis

What groups are Triploplastic?

All animals in Bilateria

What is the development of embryonic layers for Triploblastic animals?

Endoderm becomes digestive tract and some organs (lung, liver), Mesoderm becomes muscles and most non-digestive organs, Ectoderm becomes Central Nervous System and Epidermis