BIOL 371-Theme 5 Animals

In animal repodruction, new individuals are prodcued from...

preexisting individuals;

Normally, in animal repoduction, the dominant phase is the _____ and the haploid phase is the _____.

Dominant- DIPLOID

Haploid phase - GAMETES;

Normally, the zygote produced by animal reprodction is _____

DIPLOID;

The zygote must undergo ___ and ____.

growth and differentiation;

What cells gives rise to gametes?

Gonads;

What is improtant about gametes in early developemtn?

They are isolated from other things, anything that happens to other cells probably wont happen to the gametes.;

What are four ways of asexual reproduction? (just names)

1. Fission

2. Budding

3. Fragmentitaion

4. Parthenogenisis;

What is fission?

Gennetically controlled, the resulting offspring are geneticalling identical to parent (cloning)

CANNOT TELL WHO IS OG PARENT AND WHO IS OFFSPRING

What is budding?

Smaller offrping arises from the parent as an outgrowth of the body;

What is fragmentization?

Each fragment gives rise to new organism;

What is parthenogensis?

New individual arises from unfertilized egg;

What is asexual reprodctuion based on?

MITOSIS (NO MEIOSIS)

What are pros of asexual reproduction?

Dont need males to reproduce

Rapid Reprodction

Save energy

Can exploit transiet habitats (habitats that change quickly with lots of recourses because they can adapt qickly)

What are cons of asexual reproduction?

Lack of genetic variability

Any variation is due to mutation

Populaitons are vulnuarbale, a change in evironment can wipe of population;

Desribe the basics of sexual reprodcution:

Genes from both parents combine to from the zygote;

How are eggs developed?

Oogenisis;

How is sperm developed?

Spermatogenisis;

How are gametes made?

Meiosis;

What 2 things does sexual reporduction always involve?

Fertilization and growth;

What does diocious/gonochoristic mean?

Two seperate sexes;

What does monoecious/hermaphrodite mean?

(Simutlatanious vs sequential)

An indivdual has male and female reproductive organs (simultaneoulsey or at different life stages);

What are pros of sexual repodruction?

Genetic variation

Can handle environmental changes;

What are cons to sexual reprodcution?

Fertilization is complicated but nessesary

Development must proceed from zygote ALWAYS

Cost of eggs and sperm

Males do not produce offspring (in most cases);

Do the experiences of the organism/somatic cells affect the germ cells?

Germ cells are the cells that give rise to gametes, and are ISOLATED from other cells, so NO;

Where does gametogenisis take place?

In primary reproductive organ/gonad (ovaries);

What does gametogenisis consist of?

Mitosis, meisois, cell differentiation (to produce gametes that are haploid);

Where does spermatogenisis take place?

In the gonad (testes);

What are three traits of sperm (that make them highly modified and simple)?

1. Have mitochndira to provide ATP for flagellum (motile)

2. Head consits of acrosome, nucelus and centrioles

3. Few or no stored nutrients (Have optistokont character);

What is the male reporductive stragety?

Produce ALOT of small, motile cheap gametes;

What is oogenisis?

Production of the egg;

What does the egg cotnain? *3 things From who are they inherited?

Cytoplasm, organellels, and stored nutritents (yolk)

Mother!;

Where is the egg contained?

Within the vitelline membrane (zona pellucida) -Carries receptors for the sperm

Can be wrapped in jelly layer or hard shell

What is the female repoductive strategy?

To produce few, expensive, large, nonmotile, well provisioned gametes;

Desribe the male reproductive system

Gonad- Testes: Produce the sperm

Sperm Ducts: Carry sperm from tests to genital opening

Desrbibe the female reporductive system

Gonad- Ovaries: produce eggs

Oviducts: Carry them to the genital opening;

What doe external reporductive structures depend on?

Whether fertilization is external or internal;

What is fertilization?

Brining egg and sperm together (only one sperm per egg)

What is important for development for the embryo?

Embryo protection;

What are three early events in development?

1. Cleavage - to form blastula and gastrua (tissues)

2. Pattern Formation - basic body plan

3. Ogranogenisis- Fomration of organs;

What is external fertilization?

Cast gametes into external environemtn and hope they join

Gametes are nomrally smaller

Frequently high egg mortality

Coordinated gametes release - due to stimulus through courtiship movements like calls, phermone release

Also known as broadcasting spawning (Normally release a lot of eggs and alot of sperm);

What is internal fertilizatin? Spermatophores, copulation...ect

Mainly in terrestrial environments

Inside the womb- protects the embryo/gametes

Gametes have a large size differnt

Number of eggs is relativley small (to sperm)

Spermatophore: Altnerate to copulation, where package of sperm and mucus are introduced into females reproductive tarcts (spiders);

What is a challenge for fertilization?

Making sure the right sperm encoutners the egg, and only one sperm can fertilize it;

What can happen if the the wrong sperm reaches the egg in external fertiliation?

Possible interspecfic sperm egg encounters;

What is a problem if the wrong sperm ecounters egg in intneral fertilization?

Possible mating with an individual of wrong species;

What are requird to prevent the wrong sperm from reaching the egg?

Reproducive isolating mechanisms;

What are the names of the two ways to prevent polyspermy?

1. Acrosomal Reaction (fast block)

2. Cortical Reaction (slow block);

Describe acrosomal reaction

Is is fast block, where the sperm cell memrane fuses with the egg cell membrane to intitiate a wave of depolorization - any other sperm CANNOT BIND;

Describe cortical reaction

Slow block, where crotical granules fuse with egg membrane and a vitelline coat becomes impenetrable to sperm - this happens in internal and external fertilizations;

What are the mechanisms name of repoductive isolating mechanisms?

Prevents species from interbreeding or preventing fertilization

1. Prezygotic barriers

2. Postzygotic barriers;

Describe prezygotic barriers

Eggs and sperm can never encounter one another and if they do, fertilization does not take place;

Describe postzygotic bariers

Fertilization can take place, but hybrids unlikley to reproduce in turn;

What are equatic eggs/embryos protected by?

Protected by jelly;

The amniota is a.... of the amniotic egg

shared dervied character;

How do amniotes protect the embryo? What does it require?

All amniotic vertebrates have an amniotic egg

The extraembryonic membrane carry out life support function for the embryo

Has a shell that protects the internal environment

Requires INTERNAL FERTILIZATION;

What is viviparity?

The exchanges of gasses, nututrients and waste bewteen the mother and the embryo;

What does vivipariy require? What is dervied from in vertebrates?

Some sort of placenta for exchange

Dervived from extraembryonic membrane;

What is ovoviviparity?

The retention of the fertilized egg within the mothers body, with varying degreee of exchage off gassess, nutrients or wastes between mother and embryo;

What is the intermidiate step between oviparity and viviparity?

Ovoviviparity;

Early development is also called..

ontogeny;

What is ontogeny?

Cleavage to gastruatlation to moorphogenisis to organogensis to growth;

How does ontogeny happen? (mechanisms) Why?

Mitosis, gene activation/expresssion, differentiation

The zygote must give rise to complex multiceullular life;

Descirbe the ovum of the strucure

1. Vegetal Pole- primarliy yolk (nutritive tissue) and has slow cleavage - produces large cells

2. Animal Pole- where the egg nucleus is loacted, rapid cleavage- small cells;

Where is developmental information stored in?

The nucelus

Cytoplasm- maternal cyctoplasmic determinate (mRNA and proteins from mothers genome)- molecule that help direct development/differentiation of embryo;

What is cleavage?

Something the zygote immidiatly begins doing

Mitotic divison with NO INCREASE IN MASS

uses the eggs resources (radial or spiral cleavage);

What is the result of cleavage? What does it give rise to?

Morula - solid ball of cells

Blastula- hollow ball of cells (blastomeres) - has animal and vegetal pole

Cyctoplasmic determinates are distrbiuted evenly/unevenly throuhgout egg cytoplasm

What happens to the cytoplasmic diterminantes?

Cleavge divides them up, where different blasotmeres have different combination and amounts of cytoplasmic determinates;

What do blasomeres undergo?

Balostomere- hollow ball of cellsundergo differentiation where they becomes different types of cells DEPENDING ON THEIR ORIGINAL POSITION;

What determines the direction of cleavage spiral in snails?

Spatial distribution of cytoplasmic determinantes (mRNA and proteins);

Describe the development of Drosophilia

A fertilized eggs undergoes repreated division without cytokinens (syncytium)

Cytokensis occurs at blastulation

One-to-one correspondance between segmentaed larva and adult - developmental regions are landmarked (development chnages are easily followed);

How does pattern formation occur in Drosphilia? Basic

1. Bicoid: gene controlling the formation of anterior segments in the embryo

2. MAternal-effect innerticane: Expressed in female fly whihc is contributed to the egg befre fertilization;

Describe bicoid pattern formation

Maternal cytoplasmic determinant - matneral mRNA from the bicoid gene is not distributed evenly throughout the eggs

Expressed strongy at the anterior end of the egg and protein is prodcued after fertilization which diffsuss down the length to create CONCRETRATION GRADIENT

Cytokenisis in blastulation isolates the different bicoid protein concentration within an individual - acts as a transcription factor (switch genes on/off)

ANTERIOR-POSTERIOIR morpholigical acxis formed;

Describe the molecular control in pattern formaation of drosophilia

Maternal-effect genes (cytoplasmic determinant)- control polarity of egg and embryo (establish anterioir-posterior axis)

Segmentation genes- gap genes subdivide the mebryo along anterioir posteror acix (into segments)

Pair rule genes- divide embryo into untis of 2 segments with psoterioir-anterioir established;

What are homeotic genes in Drosophilia?

Hox genes that produce transcription factors which produce the segemnt-specific strucutures;

Hox genes in Drosophilia are _____ with hox genes in other taxa

HOMOLOGOUS;

Genetics of pattern formation are...

strongly conserved among animilia

Homologous genes regulate similar developmental processes or assosiated with similar processes;

What are the seven ceulular processes important in morphogensis?

1. Mitosis

2. Cell Movement

3. Selective cell adhesion

4. Apostosis

5. Induction

6. Determination

7. Differntiation

What is apostosis?

Programmed cell death (gives shape);

What is induction?

One group of cells affect developmental path taken by another group of cells through signal molecules or direct contact (think inductive effect chem);

What is determination?

Switching off most genes of a cell, only allowing certain developmental pathways to be follwoed;

What is differentiation?

AFTER determination, cells follow SPECIFIC devlopmental pathway (hence specialization through differentiation);

What is gastrulation?

Formation of ectoderm, mesoderm, endoderm, the gut and mouth/anusInitial establishment of body axes

Process by which the blastula chnages into embryo made of three germ layers (embryonic tissues);

How is gastrulation accomplished?

By the movement and differentiation of cells (morphogenisis)

What are the three germ layer/embryonic layers?

1. Endoderm- lining of gut and assosiated organs (inside)

2. Mesoderm- muscle, other internal organs, connective tissue and skeleton (middle)

3. Ectoderm- outer surface, the nervouse system (outside);

Describe frog gastrulation (4 steps)

The amount of yolk affects the form of blastula formed (therfore affects gastrulation)

1. Blastula forms

2. Gastrulation begins where cells from animal pole reach end

3. Cells migrate to inside of blastophore

4. Movment of animal half cells encolses the vegetal half cells (yolk plug);

What determins the fates of the developing embryo?

The three embryonic/germ layers;

What is the process of cell differentiation and division from the intitial three germ layers?

Organogenisis;

Describe organogenisis

Produces tissues, and the beginings of organ/organ system *same cellular mechanisms as gastrulation (7 of them)

Cell specilize and interact through cell-cell sugnal and cytoplasmic determinantes;

What is regulated in organogenisis? Why?

The expresion of the cell's genome

Each cell type has different genes on/off (determination) and cells begin producing proteins directed by those genes;

What is neurolation?

Process of cell differentitaion, growth, apoptosis that produces the dorsal hollow nerve tube in chordates

Casues folding of cytoskeletal elemtnets by reorienting neural plate;

What is neurolation induced by?

Chemical signals from notochord (induction);

Descirbe the proces of neurulation in chordates (4 steps)

1. The centre of the neural plate sinks and the edges elevate

2. The edges move closer together

3. The edges fuse together, which closes the neural tubule (nerual crest- vertebrates)

4. Neural tubes pinches free, and the ectoderm is able to close over the tube;

What are the 2 types of later development?

1. Direct development- new indivivual is similar to the adult

2. Indirect development- new individual is different from adult, and undergoes metamoprohsis;

What is metamorphosis?

The process of going from an imature organisms (not developed) to a developed one ;