Heterotrophs:obtain energy and nutrients from other organisms

     -Intracellular digestion

multicellular eukaryotes: cells that lack a cell wall

animals have tissues that develop from embryonic layers

Monophyly

(animals)

supported by morphology and by molecular data

animals have unique junctions between their cells such as:

     -Gap junctions

     -desmosomes

     -tight junctions

extracellular matrix

     -collagen

     -proteoglycans

during the cambrian explosion. they can be classified by developmental patterns and body parts.

     -development begins immediately after fertilization

flagellated sperm fertilizes an egg

zygote: a fertilized egg

most of the life cycle of animals is spent in the diploid stage

When does a zygote undergo cleavage?

(animal development)

 immediately after fertilization

Blastula

(animal development)

multicellular stage when cells are arranged in the form of a hollow ball

Gastrula

(animal development)

cup shaped multicellular stage where tissue layers form

Gastrulation

(animal development)

transfromation from blastula to gastrula stage

How do Cleavage patterns vary?

(animal development)

It depends on the yolk of the egg

Incomplete Cleavage

(animal development)

occurs when there is a large body of yolk concentrated in one part of the egg. when this happens, the embryo develops on top of the yolk mass

Complete Cleavage

(animal development)

occurs when the yolk is evenly distributed throughout the egg

Radial Cleavage

(complete cleavage, animal development)

fertilized egg divides evenly, cells allign one above another.

     -ancestrial state

Spiral Cleavage

(complete cleavage, animal development)

egg divides evenly, planes of cell division diagonal to the vertical axis of the embryo

how are animals sometimes classified

(animal development)

animals are sometimes classified by the # of cell layers that will eventually differentiate into tissues

1)Diploblastic:2 layers;an outter ectoderm and an inner endoderm

2)Triploblastic:3 layers;ectoder, endoderm and mesoderm that lies between them

What 2 major groups are Triploblastic animals divided into?

(animal  development)

Protostomes:the mouth develops from the blastopore and the anus develops later

Deuterostomes:the anus develops from the blastopore and the mouth forms later

the general structure of an animal the arrangement of its organ systems and the integrated function of its parts

     -body symmetry

     -structure of the body cavity

     -body segmentation

     -external appendages

Body Symmetry

(animal body plans)

1)Radial Symmetry:a body shape with many equal parts radiating outward

     -Cnidarians

     -Echinoderms

2)Bilateral Symmetry:a body shape with a central longitudinal plane that divides the body into 2 equal but opposit halves

Cephalization

(animal body plans)

an evolutionary trend toward the concentration of nervous tissue and sensory organs on the anterior end of the body

Acoelomate

(animal body plans)

animal that lacks an internal fluid filled body cavity

     -flatworms

Pseudocoelomate

(animal body plans)

animal that has an internal fluid filled body cavity that is completely lined with mesoderm tissue

     -earthworms

Coelomate

(animal body plans)

animal that has an internal fluid filled body cavity that is completely lined with mesoderm tissue

     -earthworms

How do body cavaties facilitate movement

(animal body plans)

they act as hydroskeletons which is controlled by longitudinal & circular motions.

body segmentation increases control over movement and facilitates specialization of different body regions

What functions do appendages have

(animal body plans)

-locomotion

-feeding appendages

-antennae

-production

what do animals have to do to gain energy

(animal body plans)

animals have to expend energy to gain energy

Sessile organisms

(animal body plans)

animals that stay in one place

motile organisms

(animal body plans)

animals that can move around

Filter feeders

(animal feeding)

capture small organisms delevered to them by the environment

     -many sessile organisms are filter feeders such as bryozoans and polysachaetes

     -they still expend energy by keeping the water moving

Herbivores

(animal feeding)

gain energy by eating plants

     -they usually don't expend energy in finding plants

     -they expend energy by trying to digest what they eat and by detoxification

Predators

(animal feeding)

gain energy by eating animals

     -expend energy by capturing and subduing their prey by hunting, stalking, and by sitting and waiting (which requires camouflage)

     -many predators use toxic chemicals like snake venom

Detritivores

(animal feeding)

obtain their energy by feeding on decomposing organic matter

     -carry out important ecosystem functions by contributing to nutrient cycling

            -earthworms

            -millipedes

            -etc.

Omnivores

(animal feeding)

change diets

everything from embryonic development, birth, growth, reproduction and death

Direct development

(animal life cycles)

newbors closely resemble adult organisms

Metamorphasis

(animal life cycles)

radical changes between larval and adult forms

     -butterflies

Sessile dispersal stage

(animal life cycles)

usually disperse eggs or larvae

Motile animals dispersal

(animal life cycles)

disperse as jouveniles or upon reaching sexual maturity

Parasite dispersal

(animal life cycles)

often rely on host species for dispersal

     -some on multiple hosts

-sponges

-placozoans

-eumetazoans

   -diploblastic animals

   -bilaterians (triploblastic animals)

               -protosomes

               -deuterostomes

the simpliest animals

     -no distinct tissue layers

     -no distinct organs

Have some specialized cells

     -Choanocytes (collar cells)

     -resemble choanofylagellates

     -spicules (structure)

     -spongin (collagen protein)

water particles suspended in water

     -water passes through the body (aided by choanocytes)

Most sponges are hermaphrodites

not much is known about these animals because there isn't much to know

     -they are diploblastic

     -they have no mouth, no gut, no nervous system

discovered in aquaria and studied in aquaria

      -never studied in nature

Ctenophores

(Eumetazoans)

comb jellies

     -diploblastic

     -radial symmetry

     -use cilia for locomotion

     -use sticky mucus secretion to capture prey

Cnidarians

(Eumetazoans)

diploblastic

   -have a gastrovascular cavity instead of a gut

radial symmetry

polyp & medusa stage

capture prey using specialized cells called cnidocytes with nematocytes

Anthozoans

(cnidarian, eumetazoan)

sea anemones & corals

Hydrozoans

(cnidarian, eumetazoan)

hydra

Scyphozoans

(cnidarian,eumetazoan)

jellyfish

Bilaterians

(eumetazoan)

triploblastic animals

     -protosomes

     -deutrostomes