Exam 3

Ch32,33,34,53

(32) Heterotrophy

Obtain energy and organic molecules by ingesting other organisms

(32) Multicellularity

Many have complex bodies

(32) Animals have no cell walls

They lack rigid cell walls and are usually flexible

(32) Tissues

Cells of most animals are organized into structural and functional units called tissues

(32) Tissues- muscle and nervous tissues

Allow for active movement

(32) Active movement

Most move more rapidly and in more complex ways

(32) Sexual reproduction

Most animals reproduce sexually. Diploid phase dominates

(32) Haploid gametes produced by

Meiosis

(32) Haploid gametes

Eggs are non mobile and sperm is mobile

(32) Fertilization results in

Diploid zygote

(32) Embryonic development

Zygote first undergoes a series of mitotic divisions that produce a ball of cells

(32) Body plans

Particular set of morphological and developmental traits, integrated into a functional whole- the living animal

(32) Taxonomists defined the major branches of the phylogeny by the evolution of the following traits:

Presence of tissues (para/eu,eumetazoa)

Symmetry

Body cavity

Embryonic development

Segmentation

(32) Tissues- zygotes are

Fertilized eggs and totipotent

(32) Totipotent

Can give rise to all other body cells

(32) As embryo develops,

Cells specialize

(32) cell specialization is _________ except in ________

Irreversible

Sponges

(32) Sponges

Parazoa

Simplest animal

(32)Parazoa

Defined tissues and organs are not present

(32) Sponges have the ability to

Disaggregate and aggregate their cells

(32) Eumetazoa

All other animals

Distinct and well defined tissues

Irreversible differentiation for most cell types

(32) Symmetry in sponges

Lack any definite symmetry

(32) All other animals have symmetry

Defined along an imaging axis drawn through the animals body

(32) 2 types of symmetry

Radial and bilateral

(32) Radial symmetric

Organisms are also diploblasic

(32) Bilateral symmetry

Evolved at the same time as animals and became triploblastic

(32) triploblastic

3 germ layers

(32) Bilateral symmetry advantages over radial symmetry

Cephalization

Directional movement

(32) Cephalization

Evolution of a definite brain/head area

(32) Germ layers are also known as

Tissue layers

(32) Most animals have embryos that produce

3 germ layers-triploblastic

(32) Triploblastic body

Outer ectoderm (body coverings and nervous system)

Middle mesoderm (skeleton and muscle)

Inner endoderm (digestive organs and intestines)

(32) All triploblastic animals have

Bilateral symmetry

(32) Cnidarians are

Diploblastic

(32) Cnidarians have an

Endoderm and ectoderm

(32) Sponges lack

Germ layers

(32) Body cavity

Space surrounded by mesoderm tissue that is formed during development

(32) 3 basic kinds of body plants

Acoelomates (compact

Hemocoelomates

Coelomates

(32) Acoelomates

No body cavity

(32) Hemocoelomates aka hemocoel

Body cavity between mesoderm and endoderm

(32) Coelomates aka coelom

Body cavity entirely within the mesoderm

(32) Body cavity functions

Fluid cushions the suspended organs

Fluid acts like skeleton against which muscles can work

Cavity enables internal organs to grow and move independently of the outer body wall

(32) Previous phylogenies were based on

The evolution of the coelom

(32) It is now clear that the internal cavity

Evolved many times and is not a reliable character to infer phylogenetic relationships

(32) Coelom appears to have evolved

Once but some clades have reverted to Acoelomates or pseudocoelomate condition

(32) All deuterostomes have

Coeloms

(32) Protostomes are

Variable

(32) Basic bilaterian pattern of development

Blastula

Blastopore

Archenteron

(32) Blastula

Mitotic cell divisions of eggs form a hollow ball of cells

(32) Mitotic cell divisions

Cleavage

(32) Blastula indents to form

A 2 layer thick ball with blastopore and archenteron

(32) Blastopore

Opening to the outside

(32) Archenteron

Primitive gut

(32) Bilaterians divided into 2 groups

Protostomes

Deuterostomes

(32) Protostomes

Develop the mouth first from or near the blastopore

(32) Protostomes anus (if present) develops either

From blastopore or another region of embryo

(32) Deuterostomes

Develop the anus first from blastospore

Mouth develops later from another region of the embryo

(32) Protostomes and deuterostomes

(32) Cleavage patterns of embryonic cells

Spiral cleavage

Radial cleavage

(32) Protostomes cleavage pattern

Spiral cleavage

New cells form to the right or left of previous cells

(32) Deuterostomes cleavage pattern

Radial cleavage

New cells form on top of previous cells

(32) Developmental fate of cells

Determinate and indeterminate

(32) Protostomes cell development

Determinate

Cell fate is determined early

(32) Deuterostomes cell development

Interdeterminate

Cell fate is not determined until after several division

(32) Evolution of segmentation provides 2 advantages

Allows redundant organ systems in adult such as occurs in the annelids

Allows for more efficient and flexible movement because each segment can move independently

(32) Segmentation appeared several times in

Evolution of animals

Anatomy and embryology have been used previously to

Infer phylogeny

(32) Animal Phylogeny sequence data have accumulated

May suggest differnt phylogenetic relationships

Has resolved some problematic issues with previous phylogeny

(32) Relationships among living animals are

Reflected in their phylogeny

(32) All animals share

Common ancestor

(32) Sponges (porifera) are the

Sister group to all other animals

(32) Eumetazoa (true animals) is a

Clade of animals with tissues

(32) Cnidaria

Branch off evolutionary tree before bilateria

(32) Most animal phyla belong to the clade

Bilateria

(32) Clade Bilaterians

All of which are invertebrates, except Chordata, which includes vertebrates

(32) Invertebrates

Animals that lack a backbone

(32) Vertebrates

Animals with backbone

(32) Bilaterians are divided into 3 clades

Deuterostomia

Ecdysozoa

Lophotrochozoa

(32) Deuterostomia includes

Hemichordates (acorn worms)

echinoderms(sea stars and relatives)

Chordates

(32) Deuterostomia clade includes both

Vertebrates and invertebrates

(32) Ecdysozoans and lophotrochozoans are composed

Of entirely invertebrates

(32) Members of ecdysozoa

Secrete external skeletons and as they grow they shed their exoskeleton

(32) Ecdysis process

Ecdysozoa shedding their exoskeleton as they grow

(32) Lophotrochozoa is

Another clade of bilaterian invertebrates

(32) Lophophore

Lophotrochozoans feeding structure

(32) Trochophore larva

Distinct developmental stage of lophotrochozoa

(32) Origin of multicellularity requires the

Evolution of new ways for cells to adhere and signal to each other

(32) Choanoflagellates and animals have sequence similarities in

Genes involved in adherence and attachment

(33) invertebrates

Animals that lack a back bone

95% of known animal species

(33) Phylum porifera

Sponges

Among the most abundant animals in deep ocean

(33) Sponge characteristics

Sedentary or sessile

Parazoa

Asymmetric

Reproduce sexually and asexually

Filter feeders

(33) Parazoa

Lack true tissues

(33) filter feeders

Water comes in Ostia and exits out osculum

(33) 3 functional layers of sponge body wall

Outer epidermis

Mesohyl

Lining of internal cavity

(33) Sponge outer epidermis

Made up of flattened cells

(33) Sponge mesohyl

Middle layer- gelatinous matrix

Spicules

Spongin

Amoebocytes

(33) Spicules

Needles of calcium carbonate

(33) Spongin

Tough protein fibers

(33) Amoebocytes

Transport