1. Cnidaria and Ctenophora 2. Jellyfish, sea anemones and corals (no front or back, weak swimmers, interact with their environment from all directions)

Exam 1 Flashcards by Mariya Shields

How many major phyla of living multicellular animals?

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What is a group of species that share the same level of organizational complexity?

Grade

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What are the 5 different grades? (simple to complex)

Cells

Tissue

Organ

Organ System

Organism

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5 hierarchical levels of complexity

Protoplasmic grade of organization

Cellular grade of organization

Cell-tissue grade

Tissue-organ grade

Organ-system grade

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Protoplasmic grade of organization

Unicellular organisms

Protists are the simplest eukaryotes
Carry out life functions among the

various cell structures

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Cellular grade of organization

Metazoans are multicellular animals that have specialized cells for particular functions

Volvox, sponges are some of the simplest metazoans

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Cell-tissue Grade

tissue- specialized cells are grouped together to perform as a coordinated unit (jellyfish)

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Tissue-organ Grade

tissues are assembled into organs (heart = muscle tissue, connective, nervous, and epithelial)

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Organ-system Grade

The highest level of organization, organs work together to perform some functions
Basic body function-circulation, respiration, and digestion

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What does animal body plans differ by?

Grade of organization
Body symmetry
Number of germ layers
Type of body cavity

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Spherical symmetry

occurs when any plane passing through the center divides the body into mirrored halves
(mostly protists)

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Radial Symmetry

more than two planes passing through the longitudinal axis can divide the organism into similar halves
EX: jellyfish

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Biradial Symmetry

two planes will divide the organism
EX: comb jellies

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Radiata Phyla

Cnidaria and Ctenophora
Jellyfish, sea anemones and corals (no front or back, weak swimmers, interact with their environment from all directions)

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Bilateral Symmetry

organisms with one plane that divides the organism into left and right halves
better for directional (forward) movement

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Bilateral symmetry is associated with what?

cephalization
1. Differentiation of a head
2. Moving head first - directional movement
3. Nervous tissue
4. Sense organs - responds to environment

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Transverse Plane

Anterior-posterior divison

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Frontal Plane

Dorsal-ventral divison

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Sagittal Plane

right and left halves
Proximal - distal
Medial - lateral

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Body cavity is

internal space
Digestive tract, second fluid-filled cavity
Blastula stage –> Gastrula Stage

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Pseudocoel or coelom

fluid filled body cavities that cushion organs and provide support

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The blastocoel usually fills with what?

mesoderm

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What 3 body plans are possible?

Acoelomate (no body cavity)
Psuedocoelomate (body cavity between endoderm and mesoderm)
Coelomate - body cavity surrounded by mesoderm

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Coelms surrounded by mesoderm can arise in which 2 ways?

Schizocoely and Enterocoely

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Mesodermal cells fill the blastocoel, forming a solid band of tissue around the gut, then a space opens inside the mesodermal band

Schizocoely

Portions of the gut lining form pockets that pinch off and form a ring of mesoderm

Enterocoely

Schizocoely and Enterocoely are the same or different?

Same

Sponges develop only to what?

They only develop to blastula stage, then reorganize to form adult Gastrulation allows animals to proceed to tissue level organization

Diploblastic

2 germ layers Cnidarians Ctenophores

Triploblastic

3 germ layers Has mesoderm

In some organisms the gut does not...

form a complete tube (waste comes back out of mouth)

A complete gut....

forms a tube within a tube body plan

Metamersim (segmentation)

1. Serial repetition of similar body segments 2. Greater mobility 3. More complex structure and function

A group of similar cells specialized for performing a common function

Tissue

What are the 4 main categories tissue is classified into?

1. Epithelial 2. Connective 3. Muscle 4. Nervous

Increased complexity allows for an increase in what?

Body Size

Larger size decreases the surface area to

volume ratio

Cost of maintaining body temperature is less per gram of body weight than in

small animals

Energy costs of moving a gram of body weight over a given distance less for

larger animals

The science of ordering and naming species

Taxonomy

A subsidy of ____ the study of variation among species and their evolutionary relationships with other species

systematics

Taxonomic ranks

1. Domain 2. Kingdom 3. Phylum 4. Class 5. Order 6. Family 7. Genus 8. Species

Binomial nomenclature

bi=two nomial=name

Descent modification

species evolved from recent common ancestor

Species are the smallest grouping of an ...

organsim

Reproductive exclusivity

cannot viably reproduce with other species

Morphological species (B.D Before Darwin)

species were defined by fixed essential features (typically tangible/visual features)

Biological species concept (A.D After Darwin)

"a species is a reproductive community of populations (reproductively isolated from others) that occupies a specific niche in nature" -Ernest Mayr

Evolutionary species concept

single lineage of ancestor-descendant populations that maintains its identify from other such lineages and has its own evolutionary tendencies and historical fate

Cohesion species concept

the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms

The environmental conditions in which a species may live

Niche

Speciation/evolution happens over generations not within...

an individual

Environmental conditions are

heterogenous (different between multiple locations)

The discipline that relates all extinct and extant species

phylogeny

Organism have features that we call

characters

The character is the

limb arrangement

The different types of limb arrangement are different

character states

Character states are

related to each other

A group we know is close but not included in the group we are studying

outgrip

Fundamental unit to group species within phylogenetic trees

Clade

Group includes most recent common ancestor and all descendants

Monophyletic group

Group includes most recent common ancestor and some descendants

Paraphyletic group

Group does not include the most recent common ancestor of all members in the group

Polyphyletic Clade

Protists

Unicellular

Porifera

cell level organization

Way an animal interacts with its living environments

community ecology

Sponges provide structures for many organisms we will call these organisms...

commensals

Sponges provide a place to hide from

predators

Sponges are..

sessile (meaning they don't move)

Flagellated cells used to move water

choanocytes (suspension feeding)

Sponges are porous, allowing water to enter through

ostia (can filter up to 1500 liters

Particles are collected at choanocytes, which absorb the particles through

phagocytosis

Water enters the sponge through these pores

Ostia

The inner cavity of the sponge

Spongocoel

Move water along and collect food particles

Choanocytes

Water exits the sponge

Osculum

Cells called Spicules line the sponge, provides

rigidity and structure

3 main designs of the sponge:

1. Asconoid: simplest 2. Syconoid: Slightly larger and more complex 3. Leuconoid: Most complex

Asconoid

1. Simplest organization 2. Singular spongocoel with choanocytes lined on either side 3. Limited in size

Syconoid

1. Tubular shape like asconoid, but more complex 2. Canal structure forms from "S" shaped edge of sponge 3. More surface area = more places for choanocytes to collect food particles

Leuconoid

1. The most complex and uniquely shaped 2. Tiny chambers lined with choanocytes

Cnidaria family:

1. True jellyfish 2. Anemones 3. Corals 4. Hydras

Ctenophora family:

Comb jellies

All Cnidaria and Ctenophora are:

1. Diploblastic 2. Radial Symmetry 3. Tissue Level Organization

The most common cnidocytes are called

nematocyst

Phylum named from cells called

cnidocytes

The two stages dimorphism in cnidaria can exist in is

polyp and medusa

Polyp

sessile (stationary)

Medusa

free-swimming

Food travels through radial canals into

ring canals

Waste diffuses out or exists through the

mouth

Predominantly located near the mouth and tentacles

Sensory cells

"Nerve net" formed withs sensory and nerve sells that send signals across the jellyfish

Nerve Cells

sense and nervous control concentrated in the head (anterior)

Cephalization

Cephalization and bilateral symmetry in almost all

triploblastic animals

Body symmetry:

1. Simplest animals with primary bilateral symmetry 2. Triploblastic with well defined mesoderm 3. Simple nervous, excretory, and osmoregulatory systems appear