Biol 191 week 9 intro to kingdom animalia

Animal (Metazoa)

Multicellular eukaryotic organism that is:

heterotrophic

Has specialized cells

Has diverse body plans

Characterstic’s of animals

Multicellular eukaryotes

Specialized cells

Heterotrophic

Often have diverse body plans

Are capable of locomotion

Have nervous and muscle systems

Respond rapidly to stimuli

are diploid and sexually reproducing

produce sperm and eggs

do not have alternation of generations

Determinate growth

Organism develops into a fixed body form

Body plan is set early in development

Indeterminate growth

Plants and fungi

Embryonic development

Process animals undergo where the body plan is established early

Used to understand evolutionary relationships

Origin of animals

Animals originated > 700 million years ago

Ediacaran biota

Earliest known animal fossils (~560 MYA)

Represents early multicellular life before the Cambrian

Cambrian explosion (radiation)

Perio of rapid diversification of animals where:

Major body plans evolved

Large animals increased

lasted ~10 million years

Possibly driven by Hox gene mutations

Developmental genes (general)

Act like switches

Turn other genes on/off

determine body segments

small changes → major evolutionary differences

Symmetry

Arrangement of body parts relative to an axis

animals often exhibit symmetry as part of their body plan

Radial symmetry

Body arranged around a central axis

Multiple planes of symmetry

no head region

Bilateral symmetry

Body divided into left and right halves

associated with cephalization (head)

directional movement

Germ layers

Embryonic layers that form tissues/organs

ectoderm

endoderm

mesoderm

Diploblast

animal with

2 germ layers: ectoderm + endoderm

Triploblast

Animal with 3 germ layers

includes mesoderm

allows complex body structures

Coelom

Fluid filled body cavity

located between the gut and body wall

fully lined by mesoderm

Acoelomate

animal with no body cavity

Pseudocoelomate

Animal with partially lined body cavity

Eucoelomate (coelomate)

Animal with true coelom fully lined by mesoderm

Blastopore

First opening in embryo

Protostome → mouth

deuterostome → anus

Protostome

Blastopore becomes mouth

Deuterostome

Blastopore becomes anus

Cleavage

Early embryonic cell division stage

rapid divisions

no increase in size

Metazoa

All animals

Parazoa

animals with no true tissue Ex: sponges

Eumetazoa

Animals with true tissues

Lophotrochozoa

Protostome clade including

Mollusks

annelids

flatworms

Ecdysozoa

Protostome clade that molts includes

arthropods and nematodes

Poriferans (sponges)

simple animals that lack true tissues

have asymmetrical bodies

are made of aggregated cells

Choanocyte (collar cell)

Sponge cell that

has flagellum

creates water flow

captures food

Amoebocyte

Sponge cell that

is mobile

is totipotent (can become other cells)

digests and distributes food

Osculum

Large opening in sponge where water exits

Pores (ostia)

small openings where water enters sponge

Filter feeding (sponges)

Process where

water flows in through pores

food particles are captured

water exits through osculum

Spongin

Protein in sponges that provides structure and remains flexible

Spicules

Structural elements in sponges:

made of silica or calcium

can form glass-like structures

Cnidaria

Phylum including

jellyfish

corals

sea anemones

Cnidarian classes

Hydrozoa

Scyphozoa

Anthozoa

Cubozoa

Myxozoa

Myxozoa

smallest animals

obligate parasites

have complex life cycles

The last common ancestor of all animals was probably a

Protist

According to the evidence collected so far the animal kingdom is

Monophyletic

What is unique to animals

Nervous system signal conduction and muscular movement

Animals probably evolved from colonial protists. How do animals differ from these protist ancestors

Animals have more specialized cells

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by

Ingesting it

A fluid or air filled space located between the digestive tract and the outer body wall

Coelom

A central cavity with a single opening in the body of certain animals including cnidarians and flatworms that functions in both the digestion and distribution of nutrients

gastrovascular cavity

The innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancrease, lungs, and the lining of the digestive tracts in species that have these structures

Endoderm