Bio 5b midterm 1 ucr

monophyletic group

- all ancestors from common ancestor - a natural group with everything in it

Hirudinea

- mainly fresh h2o and moist land habitats - highly modified --> derived from oligochaetes - mostly sedentarians -body flattens (expands to hold large meals) -NO setae or parapodia -segmentation REDUCED (& undifferentiated) -coelom largely filled w/ mesenchyme --> largely acellular - predators, scavengers and parasites on blood

What forms first then second in the blastopore of the deuterostomes?

-Anus then mouth - deutero = second -stome = mouth

Prokaryotes: photoautotrophs VS chemoautotrophs

-Photo use light for energy but chemo use inorganic compounds, still use CO2 as carbon source - many photosynthetic prokaryotes and mostly plants VS chemoautotrophs are only some prokaryotes

2 basic body forms of cnidarians

-Polyps - cylindrical and sessile --> mouth and anus combined (oral/ top end) --> mesoglea --> largely acellular -Medusa - umbrella-shaped and free-living (flipped polyp) --> thicker mesoglea --> top is ABORAL end, bottom is ORAL end --> mouth and anus combined

Myriapoda

-centipedes and millipedes ->head region followed by many segments

Prokaryotes are

Bacteria and Archaea

Taxonomic categories

(in order of least to most inclusive) -Domain - Kingdom -Phylum -Class -Order -Family -Genus -Species

Gram + vs Gram - cell wall

+: simple cell wall structure -: complex, contain lipopolysaccarides

Phylum Athropoda body plan

- "jointed feet" - opne circulation (hemocoel) - hard exoskeleton (cuticle) made of chitin and proteins - jointed appendages (often highly modified) - segmentation (metamerism: serial repetition of body parts) --> segments contain subdivisions of organ systems -tagmosis: grouping of segments into specialized units

3) #, development and arrangement of germ layers : embryonic cell layers that lead to 3 cell types

- 3 cell types: endno,ecto, and mesoderm --> germ layer formation begins w/ first cell division in zygote on way to becoming multicellular embryo - through cell movement blastula becomes a hollow sphere -Invagination of blastula called gastrulations --> process forms the first 2 germ layers and makes diploblastic embryos a) endoderm: on the inside b) ectoderm: on the outside

Chitons

- Class Polyplacophora = "many shells" -Phylum Mollusca - grazing animals that cling to rocks - ALL marine - body symmetrical - trochophore larvae - multiple calcified plates --> body slightly flexible - mantle cavity along each side of the foot - multiple gills

Protists

- INDEPENDENT life as a SINGLE cell - very diverse - mostly unicellular - very old (over 2 BYO) - diverse modes of locomotion --> flagella, cilia, crawl, swim, pseudopodia - structurally and nutritionally diverse --> complex and unique organelles

adult body plan of nematodes w/ Pseudocoelome

- NO mesodermal tissue around gut - cutely (constant cell #) to varying degrees -complete gut w/ mouth and anus; allows constant flow of food processing and permit specialization of gut regions --> food pushed w/ pharynx - NO circulatory system; Pseudocoelome provides heat transport -cuticle provides protection and leverage for muscle action *- NO GUT= NO MOTILITY

coelom formation in protostomes VS deuterostomes

- P: schizocoelom and mesoderm -P: coelom forms by splitting of mesoderm - D: entercoelom and mesoderm - D: coelom forms by out pocketing of gut

2) fundamental symmetry : the "directionality" of the body plan

- Radiata: exhibits RADIAL symmetry --> sessile animals (normally immobile) but NOT always - most animal phyla are Bilaterians - Bilateral symmetry: in animals that move; one end (head) encounters new environment and other end (anus) has propulsion

pentaradial symmetry

- after coelom formation, larvae goes through a bilaterally symmetric stage that develops asymmetrically -at early metamorphosis, left side of coelom grows and right side degnerates - subsequently, coelom forms 5 branches that guide growth

Chromalveolates: Apicomplexans ("complicated tip")

- all parasites of animals - name from apex organelles in infective stages that penetrate into host - ex) plasmodium (malaria), we developed an anti-infection but eventually were compromised due to natural selection overcoming medicine

Eucolomates

- animals with a true coelom - in coelomates the coelome is lined with the mesoderm, providing muscle in gut to power gut motility - coulombs and their lining develop in 2 ways, first looking at coelomate protostomates

Lophotrochozoan protostomes

- annelids and mollusks - phylum annelida (little rings, segmented worms) - structurally diverse but ALL SHARE standard coelomate features: --> cephalization, bilateral symmetry, complete gut - circulatory system (overcomes diffusion limit) - worm like shape w/ hydrostatic skeleton

Flatworms (Phylum Platyhelminthes)

- bilaterian acoelmotaes (no cavities) -motile; mesoderm provides muscle for locomotion - cephalized: concentration of nervous tissue and sensors in front (brain) - have posterior axis (anterior = anus) -NO circulatory system - gut w/ singular opening --> eats animal tissue (scavenger/parasite.predator) - often hermaphroditic (male and female gonads)

Bivalves

- clams, scallops, oysters, mussels - * TWO shells connected w/ hinge and closed w/ muscle - generally sedentary and burrower

Dueterostomes

- cleave: radial, indeterminate (cell fates established later) - mesoderm formation: endodermal, from archenteron -origin of coelom: from gut = enterocoely; however vertebrates show schizocoely - blastopore forms: THE ANUS first, mouth second

1) Hydrozoa (hydra, etc.)

- complex life cycles -allow w/ polyp form; sometimes medusa - sometimes colonial w/ specialized individuals (clones) forming the complete "animal"

Crustaceans

- diverse - primarily aquatic, few terrestrial - most show considerable tagmosis ; often a fusion of head and thorax into a carapace -ex) crab, lobster, shrimp, etc

Origin of eukaryotes

- eukaryote origin presumably from Archean prokaryote - suggests eukaryotes came from merging of genomes from BOTH bacteria and archaean ancestors --> endosymbiosis : organelles have own DNA via engulfing and merging into one cell

Trilobites

- extinct - many segments - little specialization of appendages - little tagmosis

Swimming with flagella

- flagella longer than the wavelength - can see several "waves" in a beating flagella - propulsion forces move parallel to major axis of flagella

prokaryote phylogeny and diversity

- formerly thought to be one group: MONERA - now composed of 2 domains: BACTERIA + ARCHAEA - data shows early diversion and long period of independent evolution

2) Scyphozoa ("true" jelly fish)

- free swimming -typically divided into Scyphozoa and cubozoa - complete life cycle - poly + medusa --> medusa stage is dominant - most feed on animals; some can get large

Turbellaria

- free-living flatworms - unspecialized; prob like ancestral worm - live in fresh H2O, moist land habitats , other marine

Tagmosis

- fusion of segments to form body regions -the change from metameric to tagmosis

Hexapoda

- insects - very diverse and highly specialized (*mouth parts*) - only invertebrates have evolved flight - social insects have most complex social system of ALL animals - 3 primary tagmata and 6 legs in 3 pairs

oligochaeta

- mainly fresh h2o and moist land habitats - mostly sedentarians --> small setae (spines) in pairs in each segment --> small unspecialized heaad --> segments relatively undifferentiated

Polychaeta

- mainly marine - structurally diverse - mostly errantians --> well developed head, often w/ elaborate feeding organs/ tentacles --> parapodia (flesh flaps) on each segments - as well as large setae (spines)

functional consequence of becoming multicellular

- many matter of size: multicellular can be larger than unicellular - diffusion is highly dependent on size: --> rapid over short distance and slow over long - single cells can't be larger than few mm --> multicellularity allows increase in organisms size WHILE cells stay small (transport systems)

coelom formation in deuterostomes

- mesoderm begins to form from the outpockets of the early gut: enterocoely (from endoderm)

Phylum Mollusca

- mollis = soft - structurally complex - unique and highly variable body plan but w/ shared characteristics - uncertain ancestry --> maybe from annelids --> unlike annelids, mollusks have trochophore larvae

Prokaryote Body Plan

- most have cell walls for structure, protection, osmotic resistance, etc - cell walls have peptidoglycans BUT differ among taxa --> gram +: simple wall structure --> gram - : complex wall structure - internally few organelles and NO nucleus

advantage to large size and multicellularity

- movement (animals): large organisms have potential to move faster -control: large size permits greater control over internal conditions (internal stability) - specialization: many cells lets some become specialized, performing fxns more efficiently

Unikonts: Amoebozoans (amebae)

- no cilia, shell or flagella - uses PSEUDOPODIA --> extensions of cytoplasm shaped by microtubules and microfilaments - pseudopodia used to move and trap food particles to be internalized using phagocytosis

polyphyletic group

- not monophyletic group - unnatural group of mixed origins

3) Anthozoa (sea anemones, coral, etc.)

- oney have polyp stage - can be structurally complex --> mesoglea more cellular than hydrozoans and scyphozoans - corals secrete calcium carbonate "house" - largest structures made by any form of life --> successful b/c of symbiosis with unicellular algae providing photosynthetic nutrients

Trematoda

- parasitic - flukes - modified for this w/ ventral and oral adhesive discs

Echinoderms

- pentaradial symmetry: after coelom formed, larvae goes through a bilaterally symmetric stage that develops asymmetrically - internal (dermal) skeleton (endoskeleton) madde of CaCO3 --> moveable in some species - internal water vascular system, derived from coelom --> connects to podia (short tentacles) / tube feet

Prokaryotes: photoheterotrophs VS chemoheterotrophs

- photo use light for energy but chemo use inorganic compounds - photo and heterosexual BOTH use organic compounds as carbon sources - photo only some prokaryotes VS chemo many prokaryotes and ALL fungi and animals

Segmentation

- repeating body segments (w/ appendages)

class Holothuroidea

- sea cucumbers - pentaradial symmetry, water vascular system (5 rows of feet) -some tube feet around the mouth modified into large feeding tentacles --> lack spines and much of the dermal ossicles --> elongated - sea cucumbers burrow or crawl; feed on debris in sand

Class Echiniodea

- sea urchins and sand dollars - pentaradial symmetry but lack arms - tube feet in 5 rows and 5 teeth - ball shaped (sea urchins) or flattened disks (sand dollars)

functional attributes of annelid body plan

- segmentation - hydrostatic skeleton - nerve net - bidirectional antagonistic muscles --> better locomotion - coelome permits internal storage or organs - NO cuticle; vulnerable to H2O loss -live in marine and moist lan habitats

Asteroidea (Phylum Echinodermata)

- simple nerve net, some central coordination - hundreds of tube feet connected to radial canals; individual controlled - predators or scavengers; feed by everything stomach onto prey and secreting digestive enzymes

Prokaryote genetics and reproduction

- single genome and single chromosome (ring like) - genome codes for only essential functions - most reproduce clonally w/ binary fission (simple) - some have gene exchange called CONJUGATION

General characteristics of prokaryotes

- small - simple structure (especially internal) *- 3 basic body forms: a) spheres coccus (berry) b) rods bacillus (e.coli) c) spiral - almost 1/2 prokaryotes species USE FLAGELLA

Gastropods

- snails and slugs -* major mod is TORSION --> 180 deg counter clockwise twist of upper portions of body relative to the foot --> occurs by asymmetrical growth during larval development - in some, radula has evolved into a drill or needle for injecting needles

Protostomate characteristics

- spiral determinate cleavage - coelom forms by schizocoely --> block of mesoderm splits to form internal cavity = coelom - anus appears second after blastopore (mouth)

1) degree of differentiation and specialization of cells and tissues

- sponges (parazoa) has UNIcellular grade of organization - sponges have few cell types and loosely organized -other animal phyla more complex ---> called Eumetazoans = "true" multicellular animals --> more specialized cells= more cell types --> cells organized into tissues with specialized fxns and separated by membranes

Cephalapods

- squids, octopus, etc. - highly modified body BUT still has basic "molluscan" parts - tentacles and "head" derived from foot - beak(and radula) in the center of ring of tentacles, often connected to venom glands -siphon (roiled up foot) can direct a water jet for rapid "jet propulsion" --> moves backwards with respect to head

Origin of multicellular organisms 1) SYNCYTIAL MODEL

- start w/ large multinucleate cell -separate nuclei by membranes into multiple identical cells -some cells become specialized

Origin of multicellular organisms 2) COLONIAL MODEL

- start w/ single cell - form a colony of identical BUT unspecialized cells (clones) - differentiate into multiple specialized cell types

Cestoda

- tapeworms -parasites of - highly specialized -NO gut, absorbed by nutrition from host -scolex: bears suckers and often hooks, which are used for attachment to the host -body covering is a tough cuticle, through which food is absorbed

Excavates: Euglenozoans

- whip like flagellum w/ unique structure for swimming - a flagellum longer than wavelength to be used as propulsion force parallel to flagellum axis - some complicated organelles --> eyespots, chloroplasts, kinetoplasts (extra DNA) - some free living, some parasitic

Triploblastic animals

-3 germ layers - Platyhelminthes OR flatworms -NO BODY CAVITY = ACOELOMATE (cause of divergence)

paraphyletic group

-A monophyletic group in which some descendants of the common ancestor have been removed. -(NOT clades)

Acoelomate

-A solid-bodied animal lacking a cavity between the gut and outer body wall - NO body cavity; space between ecto and endoderm is the mesoderm

Pseudocoelomate

-An animal whose body cavity is NOT completely lined by mesoderm - body cavity derived from the embryonic blastocoel - PARTIALLY lined mesoderm

Cnidarians

-Phylum Cnidaria -a unique characteristic and unique cell type - the cnidocyte: stinging cells w/ special organelle called the nematocyst --> when cnidocil is touched or certain chemicals present, the nematocyst discharges rapidly inverting outwards

Sponges

-Phylum Porifera - NO true tissue - sessile (attached to substrate; motile larvae) - little apparent symmetry - supporting skeleton of mineralized spicules or protein secretion or both -specialized and unique cell types --> choanocytes ("collar cells") -loosely organized -can be mechanically and chemically broken down and reformed - cells are totipotent --> one cell of any can form new animal

Phylum Nematoda (nematodes or roundworms)

-Pseudocoelomate ecdysozoans - internal cavity: Pseudocoelomate, formed from blastocoel early in development -BLASTOPORE FORMS MOUTH FIRST --> protostomes: proto= 1st and stoma = mouth

What separates all other metazoans from Porifera?

-Separated by more complex body forms

Blastula and Blastulation

-The hollow ball of cells marking the end stage of cleavage during early embryonic development & -forms the blastula with a fluid filled inner cavity (blastocoel)

Coelomate

-animal that possesses a true coelom -a body cavity lined by tissue completely derived from embryonic mesoderm

Chromalveolates: Ciliates

-cilia usually occur in large # - cilia beating is coordinated to avoid working against each other --> direction of stroke can be reversed - free swimming ciliates have direction of swimming OPPOSITE the direction of stroke -cilia shorter than wavelength and beat stroke is straight --> propulsion force perpendicular to cilia axis

Protostomes vs. Deuterostomes

-clevage: spiral and cell fates determined early VS radial and cell fates determined late in devlop. -mesoderm formation: ectodermal from cells near blastopore VS endodermal from archenteron - origin of coelom: schizocoely (blocks of mesoderm splits internally to form coelom) VS enterocoely (from gut pinched off; some show schizocoely) - blastopore forms: MOUTH first then anus VS ANUS first then mouth

Phylum Athropoda - arthropoda taxonomy

-complex and controversial - most prevalent view is of 5 major subgroups: 1) trilobites 2) crustaceans 3) myriapods 4) hexapods 5)chelicerates

class Asteroidea (sea stars)

-crinoids resemble sea stars but have "feathery" arms - may be less sessile with stalks or mobile - radial and ring canals; stone canal: water vascular system, opening to outside is madreporite - cardiac and phyloric stomachs, pyloric cacae: processing food, distributing nutrients

Phylum chordata

-deuterostome development characters: Notochord: flexible rod extending rewards from "head" viscoelastic support element -- endoskeleton - dorsal hollow nerve chord -pharyngeal slits - post- anal tail, usually muscular - often evidence of segmentation (but not in all lineages)

how did plants and animals arise?

-evolved from UNICELLULAR EUKARYOTES not directly from prokaryotes - unicellular --> multicellular eukaryotes but PLANTS AND ANIMALS DIDNT INVENT MULTICELLULARITY

INTERspecific variation

-many species of organisms -very different from each other

Main features of mollusk body plan

-shell ( one or more) secreted by fleshly mantly - mouth has tongue like radula w/ rasping teeth for scraping - muscular food for locomotion and support of visceral mass -mantle cavity contains anus and ciliated gill (ctenidia) - head, foot, shell and mantle are highly modified *- in structure and organization in various mollusks, we cover only 4

Chelicerates

-spiders, scorpions, mites, sea spiders, and horseshoe crabs -2 major regions --> tagmata, anterior (cephalothorax) and abdomen - usually 4 pairs of legs on cephalothorax - 2 parts modified as claw like mouth parts - simple life cycle: eggs hatch --> mini adults

metameric segmentation

-the repetition of organs and tissues at intervals along the body of an animal, dividing the body into a linear series of similar parts or segments

binomial naming

-uses 2 system naming - Genus species (italicized) -Only first word in uppercase

INTRAspecific variation

-w/in species -each individual is diff from every other individual

3 major classes of cnidarians

1) Hydrozoa (hydra, etc.) 2) Scyphozoa ("true" jelly fish) 3) Anthozoa (sea anemones, coral, etc.)

3 major classes of flatworms

1) Turbellaria (free living flatworms) 2) Trematoda (flukes) 3) Cestoda (tapeworms)

4 basic developmental processes (zygote--> multicellular adult)

1) cell proliferation: more cells made by cell division 2)cell differentiation: cells change to various types for specialized functions BUT same genetic info 3) apoptosis: programmed process that contributes to formation of body structures 4) cell migration: embryonic cells move w/ respect to each other --> these 4 lead to complexity BUT NO change in DNA

4 fundamental properties of animal body parts

1) degree of differentiation and specialization of cells and tissues 2) fundamental symmetry 3) #, development and arrangement of germ layers 4)In Bilateria, the presence and arrangement of body cavities (coelom, coel = cavity)

what are the 3 reasons the exoskeleton is the KEY to arthropod success

1) movement requires FLEXIBLE joints in appendages 2) provides support and nutrition --> helps arthropods move on land w/ floating on H2O --> reduces evaporation = predication 3) MUST BE MOLTED (shed) to grow bigger

3 major classes of phylum annelida

1) oligochaeta 2) Polychaeta 3) Hirudinea

Mechanisms of Evolutionary Change

1. Mutation : random genetic change 2. Genetic Drift : in small pop., allele frequency change by CHANCE --> flounder + bottleneck effect 3. Gene flow: immigration of new alleles from other pop 4. Natural Selection: competition, variance in phenotype, adaptive evolution

ectoderm, mesoderm, endoderm

3 primary germ layers -endo: on the inside -ecto: on the outside -meso: germ layer present in animal embryos that will give rise to specialized tissue types (between end and ecto)

Clade

A group of species that includes an ancestral species and all its descendants

4)In Bilateria, the presence and arrangement of body cavities --> the 3 types are?

Acoelomates, pseudocoelomates and coelomates

3 domains of life

Bacteria, Archaea, Eukarya

bilateral symmetry

Body plan in which only a single, imaginary line can divide the body into two equal halves.

What are the 2 phylums of the lineage DEUTEROSTOMES ?

Enchinoderms and Chordates

What kind of fates fo specialized cells have

FIXED fates (the last development from zygote/change in time)

Phylogenesis and their trees are

HYPOTHESES

differentiation requires an ______ in differentiation

INCREASING

Some prokaryotic species have ______ membranes

Infolded - supporting aerobic or photosynthetic enzyme complexes

what does pseudocolomates body plan lack?

LACKS muscle tissue in the gut = no gut motility

we expect MORE or LESS similarity in closely related species vs distantly related ones

MORE --> less time for evolutionary change from ancestral form

Are prokaryotes important to the ecosystem?

YES - especially decomposition - important for nitrogen uptake in many plants -symbionts important for animals eating plants -chemosynthetic autotrophs makeup for the absence of sunlight and is base of food chains

coelom

body cavity lined with mesoderm

radial symmetry

body plan in which body parts repeat around the center of the body

ex) intraspecific variation

differences in daily movement distance AMONG wolves (low vs high runners)

ex) interspecific variation

differences in daily movement distance BETWEEN sloth and wolf

in triploblastic animals like us: the end, echo and meso are what

endo: gut, organs, structures ecto: skin and nervous system meso: internal skeleton, muscles

phylogenetic relationships

historical patterns of species formation

Are clades monophyletic or paraphyletic?

monophyletic

Taxonomy

naming system shows degree of relationship

Choanocytes (collar cells)

pump with flagella, so chambers can't be too big.. to become bigger sponges must add more chambers

sister species

share direct common ancestors

What is the role of evolution in diversity?

to give us insight into generalities

how do we deduce phylogenesis?

w/ comparative anatomy, physiology, fossil and DNA r=evidence, etc.