bio 1108 exam 3 (herrick)

asexual reproduction

produces clones

clones

genetically identical cells or individuals

ex: binary fission in bacteria and archaeons

increase genetic diversity by horizontal gene transfer

budding

when a bud, or protrusion, forms on an organism and eventually breaks off to form a new organism

fragmentation

new individual rise by splitting of one organism into pieces

ex: molds, algae, worms and sea stars

parthenogenesis

virgin birth female produces eggs that are not fertilized by males, but divide by mitosis

ex: male bees do not have fathers

sexual reproduction

involves the formation of fusion of gametes

meiotic cell division

halves the number of chromosomes

fertilization

involves fusion of the products of meiotic cell division

spermatozoa

male gametes

ova/eggs

female gametes

zygote

result of the fusion of gametes (2n)

embryo

early stage of multicellular development; result in zygote undergo mitosis

can the same species reproduce both sexually and asexually?

yes; depending on the condition, organisms are capable of both types

sexual reproduction: when resources are low

asexual: when there is no competition and resources are abundant

why sexual reproduction?

OVERALL: because it leads to higher reproductive success

1. allows orgnaisms to adapt faster than asexual ones because rare beneficial mutations that arise in dif populations are brought together= increasing benefit of whole pop

2. allows populations to purge itself of harmful mutations more quickly than a population of asexual individuals

3. it may be a mechanism or parasite defense

asexual reproduction two-fold cost

everyone produces offspring --> exponential population growth

sexual reproduction two-fold cost

only half of population produces offspring --> slower population growth

external fertilization

egg and sperm being directly released into the environment

-higher change of failure

-to offset failure rate 1) needs lots of gametes 2) need to get sperm close to eggs

internal fertilization

fertilization takes place inside of female body; terrestrial adaption

r-strategists

organisms that produce large numbers of offspring without alot of parental investments

-more associated with external fertilization and unstable environment

-ex: fish

K-strategists

organisms who produce few offspring but put in a lot of parental investments

-more associated with internal fertilization and a stable environment

-ex: humans, primates, lions

amniotes

animals either lay eggs or give birth to live young

yolk

provides nutrients until egg hatches

amnion

membrane surrounding a fluid-filled cavity that allows embryo to develop in watery environment

-adaptation for land, more freedom from water

-ex: reptiles, mammals, birds

allantois

second membrane; encloses a space where metabolic waste collects

chorion

third membrane; surrounds entire embryo, yolk, allantoic sac (protected by egg shell)

ovipatry

"egg birth"; animals that lay eggs= oviparous

vivipatry

"live births"; embryo receives nutrition from mother and develops inside mother

placenta

organ allows nutrients to be obtained from mother

hypothalamus

master regulator of endocrine system

corpus luteum

temporary endocrine structure that secretes progesterone and inhibits GnRH, FSH and LH secretion

gametogenesis

formation of gametes

spermatogenesis

formation of sperm; primary and secondary

oogenesis

formation of ova; primary and secondary

fertilization

fusion of gametes; restores diploid chromosome content

capacitation

in female reproductive tract, changes that allow sperm to fertilize egg; includes alteration of fluidity of plasma membrane, loss of some surface proteins, changes in membrane charge

sperm passes through two layers

1) layer of follicle cells (corona radiata)

2) inner matrix of glycoprotein (zona pellucida)

polyspermy

fertilization by more than one seprm; prevented by membrane potential change of egg (fast block)

slow block of sperm?

vesicles in oocyte fuse with plasma membrane and release contents leading to modification of structure of zona pellucida

in vitro fertilization

process where eggs and sperm are brought together in a petri dish

cleavage

early cell division of zygote; larger cell fivides

blastula

hollow ball forming following cleavage

gastrula

multiple-layered embryonic sage of deelopment

-forms germ layers: ectoderm, mesoderm, endoderm

organogenesis

transformation of germ layers into organ system of the body

second and third trimester characterized by ______

fetal growth

hox gene

regulate development of major features of body form in animals

animal

heterotrophic, multicellular eukaryotes that form a gastrula during development =1.5 million species described

sponges

the most basal metazoans, lack body tissue, and guts, but have skeletal support and are chemically exotic; "porifera"

-earlies and least integrated branch

-habits: filter feeding, sexual reproduction

-do not have complex reproductive stuctures

-spicules of glasslike silica or calcium

-major contributor to seafloor communities

choanocytes

line interior surface of sponges; flagellated cells that capture food and gas exchange; "collar cells"

mesophyll

between interior and exterior layer; gelatinous mass- containing cells that function in skeletal formation and nutrient dispersal

the eumatazoa

"goof animals" have tissue

diploblastic

two tissue layers (endoderm and ectoderm)

triptoblastic

three tissue layers (endoderm, mesoderm, ectoderm)

ectoderm

outermost; tissue layers that forms skin and nervous system

mesoderm

middle layer; forms organs

endoderm

innermost; tissue layer that formed during gastrulation, forms gut

radial symmetry

many planes of symmetry; top and bottom, usually sessile float

bilateral symmetry

one plane of symmetry

-includes cnidarians, ctenophores, placozoans, bilateral organisms

the cnidarians

"stinging thread" (jellyfish, anemone, coral, etc)

-diploblastic, radial symmetry, tentacles around mouth for prey and have cnidocytes (stinging cells), incomplete digestive tract, can have a polyp stage and a medusa stage, no cephalization or nervous system (have a nerve net)

the ctenophora and placozoans

"comb carry" (comb jelly)

-diploblastic, radial symmetry and nerve net

-predators; catch prey by hanging down umbrella-like body

-placozoans: simplest and smallest animals

coelom

body cavity, surrounding gut-divides bilaterieans

acoelomate

no body cavity

pseudocoelomate

kind of has a body cavity

protostomes

blastopore becomes mouth first; spiral cleavage, cell fate is determined early in embryo development

deuterostomes

blastopore becomes anus first; radial cleavage, cell fate is set later

the lophotrochozoa

-one group od bilateral

-protostomes

-contain 17 phyla, mostly marine (small) with linmited diversity

phylum rotifera

-"wheel bearer"; cilia around mouth

-pseudocoelomate, variety of environments

phylum platyhelminthes

-acoelomates, dorsoventrally flattened, range of lifestyles

platyhelminthes trubellaria

planarians; free living or commensal, nonparasitiv

platyhelminthes trematoda

flukes; parasitic, intermediate hosts (fish, snails), definite vertebrate hosts

platyhelminthes cestoda

tapeworms; parisitic, no digestive tract, segmented, many vertebral hosts, numerous attachment organs

phylum annelida

annelids, trochophore larvae, coelomate, hydrostatic skeleton, closed circulatory system, nervous system

annelida oligochaeta

earthworms; consumer soil, hermaphrodites, cross fertilize

annelida polychaeta

clamworms

annelida hirudinea

leeches; parasitic, predatory

phylum Mollusca

trochophore larvae, coelomate, mantle structure

Mollusca gastropoda

snails, slugs; gills and anus above the head, muscular foot, radula (rasping tongue)

Mollusca bivalvia

clams, mussels, oysters; lost cephalization, use siphons for filter feeding, have a foot

Mollusca cephalopods

squids, octopus jet propulsion, muscular tentacles for prey, display comlex behavior

the ecdysozoans

second group of bilaterians, protostomes

ecdysis

molting of the cuticle; how ecdysozoans grow

-cuticle is part of exoskeleton; organic, light, flexible

phylum Nematoda

-unsegmented, pseudocoelmoate, move by undulation, live in soil, water, plants, animals, some pests and parasites

phylum tardigrada

"water bear"; segmented, microscopic, lack joint limbs, live in moss or sediment, eat plants and bacteria, can survive in extremes

phylum onychophora

"velvet worms"; live in moist leaf litter, prey on small invertebrates, segmented body, limbs not jointed, catch prey with slime

phylum arthropoda

segmented, joint appendages, stiff cuticles, open circulatory system, several types of metamorphosis

ametabolous metamorphosis

young and adult wingless, only change is in size

ex: silverfish

hemimetabolous metamorphosis

young (nymphs) resemble adults

ex: grasshopper

holometabolous metamorphosis

young (larvae) completely different from adult, pass thorugh sessile pupal stage

ex: butterfly

arthropoda subphyla chelicerate; class arachnida

spiders; 70,000 species, segmented body, joint limbs, tagmata (cephalothorax and abdomen), no metamorphosis (still molt)

arthropoda subphyla chelicerate; class xiphosura

horseshoe crab; social mating

arthropoda subphyla myriapoda; class diplopoda

millipedes; two pairs legs/segment detrivitovores

arthropoda subphyla myriapoda; class chilopoda

centipedes; one pair legs/segments, venom glands, predators

arthropoda subphyla crustacea

67,000 species, mostly aquatic, many have carapace (protects cephalothorax), compound eyes, modified legs

arthropoda subphyla crustacea; class malacostraca

crabs, shrimp, lobsters, crayfish, woodlice; largest group

arthropoda subphyla crustacea; class maxilloposa

barnacles

arthropoda subphyla crustacea; class insecta

=1 mil species named adaptations for life on land, plant coevolution; three tagma (head, thorax, abdomen), three pairs of legs

-HELLA groups; no need to know all lol...

the deuterostomes

include remainder of animals (chordates)

-synapomorphies: features of larval development and DNA

phylum hemichordates

-marine dwelling bottom feeders or filter feeders; small in size and sisters to echinoderms; pharangeal slits and dorsal hollow nerve cord

phylum echinodermata

sea stars, urchins, cucumbers, lilies; deuterostome, unsegmented, radial symmetry (some bilateral), endoskeleton, fluid filled cannals, tube feet

-larvae: bilateral sym

adult: no head, oral and aboral sides, moves in all directions

-entirely marine, bulk transport, tube feet are sensitive, highly functional and extensions of coelom

phylum chordata

vertebrates, cephalochordates, tunicates

-tunicates and lanceletes are chordates without backbones (not vertebrates)

-all have pharynx with pharangeal gill slits (in fish, form gills, but in terrestrial animals, can only be seen in developing embryos

-all have notochord, dorsal hollow nerve chord, postanal tail

notochord

stiff rod of collagen and other proteins that runs along back, providing resistance for muscles along sides; long rod of mesoderm; replaced by vertebral column