Reproduction

Question 1

What is natural selection?

Answer 1

• Selects for genes that enable an organism to survive and reproduce
• Driving force of evolution

Question 2

What is asexual reproduction?

Answer 2

-Genetically identical cells are produced from single parent cell through mitosis

Question 3

What are the types of asexual reproduction?

Answer 3

• Binary fission: division of one cell into two equal or almost equal parts (daughter cells)
• Budding: adult cell/organism grows smaller daughter cell or organism
• Vegetative reproduction: new individuals are created from parts of adults
• Fragmentation: in simple animals
• Parthenogenesis (in animals) or Apomixis (in plants) is having offspring from an unfertilized egg

Question 4

Describe sexual reproduction?

Answer 4

-Reproduction that involves the combination of genetic info. from two parent individuals (only in eukaryotes)

Question 5

What are the pros and cons of sexual reproduction?

Answer 5

Pros: genes recombine to form entirely new genome
Cons: must find mate and undergo mating

Question 6

What are the types of sexual reproduction?

Answer 6

• Ciliates undergo conjugation (genes transferred through micronucleus, micronuclei fuse together to form new genome)
• Fertilization: where two cells fuse to one, most multicellular organisms produce haploid gametes (sperm and egg produce diploid zygote

Question 7

Describe dioecious and monoecious?

Answer 7

Dioecious: organism that produces one type of gamete, male/female
Monoecious: produces both types of gametes, hermaphroditic, may or may not self fertilize

Question 8

What are spores?

Answer 8

• Haploid reproductive cell that gives rise to a gametophyte

- May form from sexual or asexual processes (always haploid)

Question 9

Describe diplontic and haplodiplontic life cycles?

Answer 9

Diplontic: only diploid stage is multicellular, haploid stage is one gamete cell
Haploidiplontic: multicellular diploid stage (sporophyte), and multicellular haploid stage (gametophyte)

Question 10

Describe chlorophytes and charophytes?

Answer 10

• Haplodiplontic life cycles
• Gametophyte and sporophyte appear identical
• +/- gametes

Question 11

Describe brown algae?

Answer 11

• Haplodiplontic life cycles
• Gametophyte is reduced, sporophyte is dominant
• Egg and sperm

Question 12

Describe Bryophytes?

Answer 12

-Haplodiplontic
-Gametophyte dominant: Archegonia (female), Antheridia (male)
-After fertilization:
Archegonia grows a sporophyte stalk
Sporophyte is nonphotosynthetic
Sporophyte produces spores
-Need to be in moist environment

Question 13

Describe Pteridophytes?

Answer 13

-Haplodiplontic
-Sporophyte dominant
Produces sori on back of fronds
Small gametophyte with antheridia and archegonia
Sperm fertilizes egg and sporophyte grows from archegonium

Question 14

Describe seed plants?

Answer 14

-Haplodiplontic
-Seed plants produce 2 kinds of gametophytes
Male gametophytes: microgametophyte (pollen grains, dispersed by wind or pollinator)
Female gametophytes: megagametophyte (develop within an ovule, enclosed within diploid sporophyte tissue)

Question 15

What is the difference between pollen and spores?

Answer 15

• Pollen: used for fertilization (sperm)

- Spores: gown into gametophyte generation

Question 16

Describe gymnosperms?

Answer 16

• Sporophyte produces male and female cones
• Pollen grains develop into male cones by meiosis
• Female cones are larger with woody scales
• When scales of female cones are open, pollen grains drift between them
• Pollen tube emerges from pollen grain which digests its way to embryo sac to deliver sperm

Question 17

What are angiosperms?

Answer 17

Possess flowers and fruits

Question 18

Describe flower structure?

Answer 18

• A complete flower has four whorls
• An incomplete flower lacks one or more whorl
• Calyx: consists of sepals
• Corolla: consists of petals
• Androecium: collective term for stamens, a stamen consists of a filament and anther
• Gynoecium: collective term for carpels, carpels consist of an ovule, ovary, style, and stigma

Question 19

What is a microgametophyte?

Answer 19

• Four microspores form through meiosis and become pollen grains
• Each consist of a tube cell, generative cell will later divide to form two sperm cells

Question 20

What is a megagametophyte?

Answer 20

• Female gametophyte has 8 haploid nuclei

- 2 become polar nuclei

Question 21

Describe pollination?

Answer 21

• Process which pollen is placed on stigma
• Self pollination: pollen from flowers anther pollinates stigma of same flower
• Cross pollination: pollen from anther of one flower pollinates another flowers stigma (more common)

Question 22

What are some pollinators?

Answer 22

• Bees: most common insect pollinators
• Butterflies: prefer flowers with flat “landing platforms”
• Birds: like red flowers

Question 23

Describe fertilization?

Answer 23

-Angiosperms undergo a unique process called double fertilization
Tube cell forms a pollen tube
Generative cell divides to form 2 sperm cells
-One sperm cell fuses with egg cell to form diploid zygote
-Other sperm cell nucleus fuses with the two polar nuclei to form the triploid endosperm

Question 24

How do fungi fertilize?

Answer 24

• Merge hyphae cells from two individuals
• Nuclei fusion in a process called karyogamy, forming a diploid zygote
• Sometimes forms a dikaryotic cell before karyogamy

Question 25

How do Basidiomycota fertilize?

Answer 25

• Spore germination leads to production of haploid mycelium
• Mycelium may fuse to result in fertilization (now dikaryotic)
• Basidiocarps (mushrooms) form from secondary mycelium
• Dikaryotic basidiocarp has hundreds of basidia in each gill

Question 26

Describe animal fertilization?

Answer 26

-Diplontic, most reproduce sexually

Question 27

Describe internal and external fertilization?

Answer 27

• Internal: sperm introduced into female reproductive tract

- External: eggs and sperm are released into water where union of free gametes occur

Question 28

Describe the three strategies of development in internal fertilization?

Answer 28

• Oviparity: Fertilized eggs deposited outside of body to complete their development
• Ovoviviparity: Fertilized egg is kept in mother to complete development and young obtain food from egg yolk
• Vivipartiy: Young develop within mother and obtain nourishment from her blood

Question 29

Describe fertilization in aquatic vertebrates?

Answer 29

• Cartilaginous fish: internal fertilization

- Bony fish and most amphibians: external fertilization

Question 30

What are amniotes?

Answer 30

• Animals with amniotic egg
• Amniotic egg has four membranes
• It’s water tight
• It results from internal fertilization

Question 31

Describe the parts of an egg?

Answer 31

• Amnion: fluid, maintains chemical consistency and temperature
• Yolk Sac: 2nd membrane, encloses the yolk of eggs full of nutrients, proteins, fats
• Allantois: 3rd membrane: stores metabolic wastes, acts as respiratory surface exchanging gases
• Chorion: 4th and outermost protective membrane fused to allantois, gas exhange

Question 32

Describe reproduction in reptiles and birds?

Answer 32

-Most are oviparous, lay amniotic egg, birds incubate egg to keep it warm

Question 33

Describe mammal reproduction?

Answer 33

• Female reproductive cycles involve periodic release of mature egg (ovulation)
• Most have estrous cycles (females are receptive to males only around ovulation, estrus)
• Primates have menstrual cycles (shed inner lining of uterus, menstruation)

Question 34

Describe the different mammals and how they reproduce?

Answer 34

• Monotremes: are oviparous (lay amniotic eggs)
• Marsupials: ovoviviparous, give birth to incompletely developed fetuses which mature in mothers pouch
• Placentais: are viviparous, retain young in uterus for long periods of development

Question 35

What is a placenta?

Answer 35

• Derived from amniotic egg and the lining of the mothers oviduct
• Embryo is plugged into mother and exchanges nutrients and waste with her
• Brings fetal and maternal blood into close contact