Chapter 30 - Intro to Animal Diversity

How do eggs protect developing embryo?

tough outer covering provides physical barrier/support. prevents embryo dessication

ecydysozoa defining characteristic. examples

undergo molting (ecdysis)

Briefly describe embryonic development. define cleavage, blastula, larva, metamorphosis

zygote undergoes cleavage (series of mitotic cell divisions), during cleavage zygote becomes hollow ball of cells called blastula, most animals develop into larva (sexually immature form that look diff from adults), larva go through metamorphosis (developmental process that converts immature animals into juvenile into adult

What is the cambrian radiation/explosion?

520 to 515 mya rapid appearance of amazing variety of body plans. modifications in this period account for many branches of animal

Describe egg and sperm of most animal organisms

Large nonmotile eggs and small flagellate sperm

Is locomotion necessary for animal classification?

No

define body plan

basic structure and functional design of body

When had all hox genes developed and what is the implication for animal diversification

beginning of cambrian period. mutations result in rapid change in animal body plans

What is segmentation (benefit) and how did it evolve in the bilateral animals

body plan with certain repeated structures that can be regulated independently evolved independently in the three clades of bilateria

What are the main variations in morphology biologists use to understand evo relations

body symmetry, tissue layers, type of body cavity, pattern of development, molecular tools

define gastrulation

cells of blastula undergo process that forms and segregates the three germ layers

What is the common ancestor of animals (group of protists)? how did this organism develop to be classified as first animal

choanoflagellates cells of colonial flag become specialized to perform specific functions. div of labor evolved and colony reach level of coordination to qualify as single organism

What is another name for a monophyletic group?

clade

What are the two types of diploblastic organisms and what does it mean? What are all other animals?

cnidarians and ctenophores only have two germ layers triploblastic

describe tube within a tube body plan

coelom is a space that separates body wall (outer tube) from digestive tube (inner tube)

describe how coelom acts as hydrostatic skeleton

contracting muscle pushing against tube of fluid. pressurized tube basically

What is a major challenge of marine habitats?

coping with waters movements and currents that could sweep them away

What is the chief problem facing terrestrial organisms? What are two primary adaptations?

dessication (drying out) 1. Body covering adapted to minimized fluid loss 2. location of respiratory surface deep in animals (ie. gills on outside, lungs and trachea deep in body)

define cephalization and the development of nervous system from it. how and what is it a adapatation for?

development of a head where sense structures are concentrated. conc of nerve cells form a brain and nerve cord extends twoward rear end of animal locomotion, head end meets enviro first and equipped to capture food, respond to danger

Beginning from choanoflagellate ancestor, name the major separations and their associated feature

differentiated tissues (sponges), radial or bilateral symmetry with three tissue layers and a body cavity, protostome and deuterostome. from protostome: molting or non molting from deuterostome: segmentation or not

define the principle of parsimony

he scientific principle that things are usually connected or behave in the simplest or most economical way, especially with reference to alternative evolutionary pathways.

What about the composition of freshwater makes it a dificult environment to live in? how to animals adapt?

hypotonic to tissue fluid of animals, so animals tend to bring in water via osmosis mechanisms of removing excess water and retaining salts (osmoregulation)

How have many terrestrial animals meet the zygote dessication challenge? How has it helped?

internal fertilization. sperm in watery medium in female, embryo might develop in moist environment of mother

lopotrochozoa characteristics (2). example organisms

lophophore, ciliated ring of tentacles around mouth for feeding type of larva called trophoore larva flatworms, ribbon worms, mollusks, lophophorate phyla

What are two major clades of protostomes?

lophotrochozoa and ecydysozoa

What is the extra germ layer in triploblasts and what does it give rise to

mesoderm - muscles, skeleton, circulatory system

Define metazoa and then eumetazoa

metazoa - animals eumetazoa - diplo/triploblastic animals

What type of group (mono, para poly) is animals

monophyletic

What are the pseudocoelomate animals and how did this body type develop?

nematodes and rotifers process of simplification from group of animals with true coelom

What is the monophyletic group of choanoflagellates, fungi, animals and what are they charaterized by?

opisthokonts posterior flagellum on motile cells

What are some of the variability in fresh water that animals must adapt to?

oxygen content, temperature, turbidity (sediments suspended), water volume, less available food

Thinking how they divide the body into specific parts, define saggital, frontal, transverse planes

saggital - right and left halves frontal - doral and ventral parts transverse - anterior and posterior

define molecular systematics

science that focuses on molecular structure to clarify evo relations

What was the first air breathing terrestrial animals? first terrestrial vertebrates?

scorpion like arthropods amphibians

What animal was Hox gene recently found in and what does this implicate evolutionarily?

sea anemone. cnidarian with radial symmetry implicating share common ancestor with bilateral animals

Where does fossil evidence show animals evolved?

shallow marine environments in proterozoic eon

What is prescence of collagen in animals referred to as in classificaiton?

shared derived charateristic

What are advantages of the true coelom body plan (2)

specialized to move quickly, space for internal organs to develop and function and be cushioned

What are four environments of marine habitats?

1. buyancy provides support 2. large volume keeps water temp stable 3. fluids of invertebrates matches osmotic conc of sea water so fluid and salt balance easily maintained 4. plankton provide ready source of food

Describe the 8 main characteristics of animals

1. multicellular eukaryotes that lack cell walls (structural proteins) 2. heterotrophs (consumers depend on producers for raw materials and energy) 3. Specialized cells that form tissues and organs and even organ systems in large animals 4. diverse body plan adapted to food and reproduction 5. MOST capable of locomotion at some time during life 6. MOST have nervous and muscle systems 7. MOST dipload organisms that reproduce sexually 8. Go through period of embryonic development

how many germ layers do bilateria have

3

How many phyla for extant animals?

35

Structurally, how do marine and terrestrial environments differ for animal body types

Water buoyancy supports animals. air is less dense and require muscle and skeletal system for support

define zygote

haploid sperm unites with haploid egg to form diploid zygote

define bilateral symmetry

divide through one plane that passes through midline of body to produce roughly equivalent right and left mirror images

What are outter and inner germ layers and what do they develop into (only two)

ectoderm - outer covering and nervous tissue endoderm - lining of digestive tube and other digetive structures

define evo devo biology

field where biologists compare molecular events like gene regulation during development in various animal groups

define sessile. What is the locomotion profile of sponges and corals?

firmly attached to ground or surface move about as immature larva and are sessile as adults

What are teh acoelomate organisms?

flatworms and ribbon worms

define coelom

fluid filled body cavity between outer wall of body and digestive tube

What is the body type of radial symmetry and which organisms exhibit it?

form of wheel or cylinder and similar structure arranged as spokes from central axis. mult planes cut through that divides organism into mirror image cnidarians (jellyfish, sea anemone), and adult echinoderms (sea stars and relatives)

What is definition of monophyletic?

group consists of ALL descendants and ONLY descendenats of a common ancestor

define biradial symmetry, who has it?

parts of body become specialized so only two planes can divide into similar halves sea anemones and ctenophores (comb jellies_

What are the challenges of reproduction on land?

protect gametes from shock and dessication

What is the first division for bilateral animals? describe differences

protostomia - cell division diag to polar axis (long) giving spiral cell arrangement (spiral cleavage). determinate cleave (removal of few cells of blastula results in loss of appendages). embryonic and blastopore generally form mouth deuterostomia - early divisions parallel or right angles to polar axis (radial cleavage). indeterminate cleavage (removal of few blastula cells develops normall, other cells make up, probably smaller). embryonic gut and blastopore generally form anus

What do the Hox genes regulate and how are they implicated in evo relationships?

regulatory genes the specify anterior-posterior axis during development number of Hox provide evo insights. identified in all bilateral animals implicated last common ancestor had them as well

How do amphibians handle reproduction?

return to water and larval form develops in the water