Bio 2 Unit 4 Test

Contain information on Intro to Animals (ch 32), The Invertebrates, and Phylum Chordata (Ch 33-34)

1st Multicellularity requirement

Cell signaling

2nd Multicellularity requirement

Cell-to-cell connections

What does cell signaling pathways rely on?

pore-like proteins that provide connection b/w cells

What are animals cells anchored by?

adherence proteins

What do all animals contain?

connective tissue collagen

What type of nerve system does animals rely on?

simple nerve network, or more complex nervous system

What does simple nerve network, or more complex nervous system provide?

rapid control of cellular function, major organ systems, muscle contraction, reflexes

Neurons

generate minute electrical impulses called action potentials that rapidly spread from cell to cell

What happens when action potentials reach a chemical synapse?

they cause the release of Neurotransmitters (signaling chemicals)

Where do synapses lie?

Between 2 neurons or between a neuron and a particular tissue/organ (heart, muscle....)

What does the release of Neurotransmitters provide?

rapid & precise control of cells & tissues “downstream”

What does Neurotransmitters released do?

diffuse across tiny gap (synaptic cleft) & bind to membrane proteins of target cell triggering cellular response

What do lines of cells within animals do?

release chemical messengers called hormones, slower than the nervous system

What do hormones do?

drift through the body’s fluids (ex, blood) and can bind target cells with the proper type of receptor proteins

What do hormones control?

homeostasis of key internal variables & coordinate growth and reproduction

endocrine system

regulates hormonal control

What do animal cells lack?

Cell Walls, just have cell membranes

Embryonic tissue layers “Germ Layers”

formed during gastrulation and consist of three primary layers—ectoderm, mesoderm, and endoderm—which give rise to all tissues and organs

Tissue

groups of similar cells that act as a functional unit

Examples of tissue

Nervous tissue and muscle tissue with work together to allow body movement

1st Characteristic of Animals

Are motile at some point in the lifecycle

2nd Characteristic of Animals

Heterotrophic

3rd Characteristic of Animals

Digest food internally

What are the closets living relative of animals?

choanoflagellate protists

What animal cell and protist look similar?

Choanoflagellates and sponge choanocyte cells

What are animals characterized by?

Their body plan (set of morphological and developmental traits)

1st Type of Animal Body Plan

Symmetry

2nd Type of Animal Body Plan

Tissue layers

3rd Type of Animal Body Plan

Body cavities

4th Type of Animal Body Plan

Type of development

Asymmetrical

lack symmetry (irregular shape)

Bilateral symmetry

a body plan where an organism can be divided into identical left and right mirror-image halves along a single, central vertical plane

1st Trait of Bilateral Symmetrical Animals

Dorsal (top) and ventral (bottom) sides

2nd Trait of Bilateral Symmetrical Animals

Right and left sides

3rd Trait of Bilateral Symmetrical Animals

Anterior (front) and posterior (back) ends

4th Trait of Bilateral Symmetrical Animals

Many have sensory equipment (brain, eyes, etc.) at the anterior end

Radial symmetry

A object or animals that is divided into identical halves by multiple planes passing through the center

How do radial animals often move?

They are sessile or planktonic (drifting or weakly swimming)

How do bilateral animals often move?

actively and have a central nervous system

How do most animals reproduce?

sexually, with the diploid stage dominating the life cycle

1st Type of Asexual Reproduction in Animals

Mitosis produces an identical daughter bud

2nd Type of Asexual Reproduction in Animals

Fragmentation

What happens after egg fertilization?

the zygote undergoes rapid cell division called cleavage

How does a zygote becomes a cleavage?

Via simple division

What does the cleavage turn into?

a multicellular, hollow blastula

What happens to the blastula after it’s formed?

It undergoes gastrulation, forming a gastrula with different layers of embryonic tissues

Ectoderm

germ layer covering the embryo’s surface (epidermis/skin, nervous tissue)

Endoderm

innermost germ layer that lines the developing digestive tube (archenteron) and gives rise to some organs (liver, lungs, etc.)

Diploblastic animals

only have ectoderm and endoderm

What animals are diploblastic?

Cnidarians and ctenophores

Triploblastic animals

have an additional middle tissue layer called mesoderm

What does the mesoderm do?

Fills the space between the ectoderm and endoderm and forms the muscles and some organs

What animals are triploblastic?

Any animal will bilateral symmetry

What does most triploblastic animals have?

A body cavity

body cavity

Fluid filled space located between the digestive tract and the outer body wall

What is a “true” body cavity called?

coelom

What is the coelom derived from?

Mesoderm

Coelomate animals

possess a “true” coelom

In coelomate animals, what does the tissue do?

surround the cavity and suspends internal organs

Pseudocoelomates

possess a body cavity bounded by mesoderm and endoderm, doesn’t completely surround the body cavity

Acoelomates

lack a body cavity

1st Function of the body cavity

In soft-bodied animals, it can act as a hydrostatic skeleton

2nd Function of the body cavity

Cushions suspended organs, prevents internal injury

3rd Function of the body cavity

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

Protostomes

blastopore becomes the mouth

Deuterostomes

blastopore becomes the rectum

1st Type of Digestive System

None

2nd Type of Digestive System

gastrovascular cavity

3rd Type of Digestive System

complete digestive tract

gastrovascular cavity

Incomplete digestive system, 1 opening

complete digestive tract

Separate mouth and rectum, allows for cephalization of parts

1st Type of coelomate circulatory system

Open circulatory system

2nd Type of coelomate circulatory system

Closed circulatory system

Open circulatory system

blood pumped through vessels that open into body cavities, organs bathed in hemolymph

Closed circulatory system

blood remains enclosed in vessels

segmentation

Repetition of body parts along the length of the body

Are acoelomates and pseudocoelomates segmented?

No

Are coelomates segmented?

They can or can’t be

Invertebrates

animals that lack a backbone

What animals belong to phylum porifera?

Sponges

Where are sponges found?

marine (mostly) or fresh water

What is the symmetry of sponges?

Asymmetrical

What is the tissue type of sponges?

None, they lack true tissue

Adult sponges’ level of motility

Sessile

Larval sponges level of motility

Mobile

Sponge Body Plan

consist of a gelatinous internal layer and various unique cells

Choanocytes (flagellated collar cells)

generate a water current through the sponge and ingest suspended food

Amoebocytes

perform several functions including digestion, nutrient dispersal, and production of spicules or spongin (collagen)

supportive skeletal fibers of sponges

function to maintain shape and/or for protection

spongin

made of collagen

spicules

made of CaCO₃ or silica (SiO₂), needle-shaped, 1-6 rays

How do sponges feed?

Filter feeders, Capture food particles suspended in the water that passes through their body

1st Class of Sponges

Class Calcarea

2nd Class of Sponges

Class Hexactinellida

3rd Class of Sponges

Class Demospongiae

Class Calcarea

spongin/CaCO₃ spicules

Class Hexactinellida

glass sponges, silica spicules

Class Demospongiae

Most lack spicules, often used as bath sponges