Theme 5 Animal Reproduction

Question 1

What is asexual reproduction

How does it occur

Answer 1

The genes are from one parent

Fission

Budding (branching off main thing)

Fragmentation (ex sea stars growing other feels to make new limb)

Parthenogenesis (developing from unfertilized egg, in stable environments)

Question 2

What are the pros and cons of asexual reproduction

Answer 2

Pros
They reproduce in isolation (good for sessile things to not depend on others)
Reproduce quickly (more flexible to diff environment conditions)

Cons
Less/no genetic variability (clones)

Question 3

What is sexual reproduction

What are the ways it happens

Answer 3

Genes from two parents

The gametes are egg and sperm

Dioecious
Monoecious/hermaphrodite
Fertilization occurs then development

Question 4

What is dioecious

Answer 4

An animal that has 1 type of gametes

Either male gametes or female gametes

Question 5

What is monoecious

Answer 5

Hermaphrodites

Simultaneous hermaphrodites: egg and sperm present at the same time

Sequential hermaphrodites: sex/gametes change depending on size and temp

Question 6

What are the pros and cons of sexual reproduction

Answer 6

Pros

Genetic variability (inherit unique combos of genes)
More complex

Cons
Slower (needs courting, good environment)
Energetically costly (costs to find mates, making gametes, risk of predation)

Question 7

What is gametogenesis

What are the two types of gametogenesis

Answer 7

Formation of gametes

Spermatogensis
Oogenesis

Question 8

What is spermatogenesis

What is the acrosome

Answer 8

It produces the sperm Which specializes in moving toward and penetrating eggs

Contains the acrosome which is a secretory vesicle of sperm that contains enzymes

Has flagellum for transportation

Question 9

What is oogenesis

Answer 9

Production of an ovum (unfertilized egg)

Stores nutrients for early development stages

Has protective coating

Can be the largest cells in the animal

Question 10

What is fertilization

Answer 10

Bringing sperm and egg together, makes zygote, first stage in early development

Having the right sperm is important for aquatic organisms where sperm and egg float around

Protection of the embryo

Question 11

What is the dominant stage

Answer 11

Diploid

Question 12

What is external fertilization

Answer 12

Releasing many small eggs/sperm into the environment

Ex. Broadcast spawning

Question 13

What is internal fertilization

Answer 13

The male deposits the sperm into the female

This comes with mating and competition

Question 14

What type of fertilization do aquatic animals do most
Terrestrial?

Answer 14

External because less risk of drying out

Internal because of dessication

Question 15

Does internal fertilization cause less or more variation

Answer 15

Less because of mating preference

Question 16

What is the process of sperm fertilizing egg

Answer 16

Sperm goes through the two layers surrounding the egg by releasing enzymes from their acrosomes to help movement through

Then the plasma membrane of the sperm and the egg fuse together and block the entrance of the other sperm though depolarize the out layer of the egg, this is the fast block cortical reaction

The sperm releases the genetic material into the egg

The cortical reaction is when the egg release calcium after sperm has entered which make a thicker layer around the egg to further prevent more sperm, this is the slow block

Question 17

What is oviparous

What does it occur in

Answer 17

Type of internal fertilization where the whole thing is in an egg, has everything it needs in the egg

Reptiles and insects

Question 18

What is viviparous

What does it occur in

Answer 18

Type of internal fertilization where the embryo is retained in the parents body

Development happens in a specialized part in body

Placenta in it helps with gas exchange, nutrient delivery and waste removal

(Most mammals)

Question 19

What is oviviparous

What does it occur in

Answer 19

Type is internal fertilization where the animal is in and egg and in the parents body

Some fish, lizards, sharks

Question 20

What is an amniotic egg

Answer 20

And egg cell that is surrounded by protected layers

The egg white provide protection

The yolk provides nuterients

The shell encases the whole thing

(Ex. Chicken egg)

Question 21

What is ontogeny

Answer 21

The steps of early development

Question 22

What are the steps in ontogeny

Answer 22

Cleavage through mitosis
Gastrulation (activation/expression)
Morphogenesis (differentiation)
Growth

Question 23

What is direct development

What is indirect development

Answer 23

Offspring looks like mini version of the adult

The offspring look diff and goes through several changes before reaching the final body plan

Question 24

How does cleavage occur in ontogeny

Answer 24

The zygote splits through mitosis into 2 cells, then again into four cells

Then is cleave many times into a morula which is a solid ball of cells. This I when the anterior and posterior axes are formed (animal pole and vegetal pole)

Then further cleavage makes a blastula (hollow ball of cells) the fluid filled cavity inside it is called the blastocoel

Question 25

What is included in gastrulation

Answer 25

The forming of the ecto endo and mesoderm, gut, mouth, anus

Has six mechanisms the transform the blastula

Mitosis
Cell movement
Selective cell adhesion
Induction (some cells induced changes in other cells)
Determination
Differentiation

Question 26

What is determination in gastrulation
What is differentiation

Answer 26

It’s brought about by induction, gets the cells determined to become diff tissues

When they actually become diff type of tissues

Question 27

What is the process of sea urchin gastrulation

Answer 27

It start at the vegetal (bottom) pole where cells there are induced to change shape and move into the blastocoel

The cells are now future endoderm cells and they invaginate (move in) to the blastocoel. this forms the blastopore (anus)

Secondary mesenchyme cells are at the top of the blastopore, primary are at the sides

The secondary mesenchyme cells extend and attach to the ectoderm (actual blastula)

This creates the mouth anus and tissues (ecto endo meso)

Question 28

How does frog gastrulation happen

Answer 28

The animal pole and vegetal pole are there but the vegetal pole (yolk) is bigger

This makes less blastocoel cavity

Gastrulation starts from the animal pole and the transforming cells migrate to the dorsal lip (side) of the blastopore and move in (invaginate)

The transformed dorsal mesoderm cells move further into the blastopore through involution and cover the entire inside of the animal pole. This displaces the blastocoel

This forms the yolk plug, archenteron, ecto endo mesoderm

Question 29

What is chordate neurulation

Answer 29

Only important for vertebrates

Is after fertilization and gastrulation

End with the formation of a hollow neural tube

Question 30

What happens in chordate neuralation

Answer 30

The notochord induces the ectoderm cells above it (the neural plate) to thicken

The cells in the center begin to sink down and form the neural crest, the crest moves in further and sinking happens more

The edges of the crest fuse together and close the neural tube

The tube pinches free from the ectoderm and cells from the tube go on to make spine, and diff cell types.