Lecture 1 (1a&b) - Maximizing Reproductive Success Flashcards
1
Q
What is the purpose of reproduction?
A
- the processs by which parents produce the first filial generation
- parental generation produces offspring = first filial generation F1
- F1 generation acts as parents to F2
- purpose of reproduction is to produce the 2nd… filial generation
2
Q
Lifetime reproductive output
A
- number of offspring born to a parent in the F1 generation
- LRO = product of fecundity (fertility) x fertile lifespan
(number of offspring x # of time you reproduce)
3
Q
What determines LRO?
A
- fecundity
- semelparous vs iteoparous
- fertile lifespan
4
Q
Fecundity
(dependent upon…)
A
- number of fertile matings
- mate density
- success in courting (and retaining a mate)
- success in mating
- fertility of individual
- feterility of partners (sexual reproduction)
5
Q
Semelparous
A
a single episode of reproduction before death
(eg pacific salmon)
6
Q
Iteroparous
A
several rounds of reproduction before death
- with same partner = monogamous
- with different partners = polygamous
polygamy:
- polygynous = 1 male, several females
- polyandrous = 1 female, several males
7
Q
Fertile life span
(dependent upon…)
A
- age at first fertile mating
- rate of devolopment (precocity)
- success in courting a mate
- success in mating
- age at last fertile mating (~= survival)
- usually determined by death
- menopause is rare
- ie mating not until death
- but exists in human females and elephants
8
Q
What is lifetime reproductive success?
A
- number of fertile offspring born to a parent in the F1 generation
- number of offspring attributable to a “grandparent” in the F2 generation
9
Q
When might lifetime reproductive success be less than lifetime reproductive output?
A
sterile matings
- eg mule is sterile
- mule = mother is a horse
- hinney = mother is a donkey
- eg tigons and ligers have decreased fertility
- liger = mom tiger
- tigon = mom lion
- lions in Africa, tigers in Asia = geographically reproductively isolated
10
Q
What determines lifetime reproductive success?
A
- LRO
- fecundity/fertility of F1
- probability that F1 survive to sexual maturity / achieve fertility
- LRS WILL ALWAYS** BE LESS THAN LRO**
11
Q
Types of asexual reproduction
A
- binary fission
- multiple fission
- budding
- fragmentation
- vegetative propagation
- apomixis
- parthenogenesis
12
Q
Binary fission
A
- parent cell splits into two identical daughter cells
- uses just mitosis
- mother cell is gone
- eg archaea, eubacteria
13
Q
Multiple Fission
A
- parent cell replicates nucleus then splits into several identical daughter cells
- mother cell gone also
- eg protista
14
Q
Budding
A
- “daughter” cell divides from “mother cell”
- mother still exists (unlike binary and multiple fission)
- eg S. cerevisiae and hydra
15
Q
Fragmentation
A
- offspring regenerate from fragments (fissiparity)
- eg annelids, turbellarians, starfish
16
Q
Vegetative propagation
A
- plants and fungi
- similar to fragmentation
- new plants develop from the buds of the runner in eg strawberries
17
Q
Apomixis
A
- agamospermy
- in plants
- asexual seeds
- no meiosis or gametes
- seeds not formed by fertilization by sperm
- eg dandelions in absence of pollinizing insects
18
Q
Parthenogenesis
A
- in animals
- unfertilized “egg” forms embryo
- invertebrates: Daphnia, rotifers, aphids, stick insects, hymenoptera (including parasitic wasps)
- vertebrates: bonnethead shark (females make babies), komodo dragos, green whiptail lizards (?), turkeys
- not naturally in mammals
19
Q
Pros of ASEXUAL REPRODUCTION
A
- simple - only need 1 type of cell division (mitosis)
- can occur in absence of partner (fast)
- avoid risks intrinsic to sexual reproduciton (eg predation, physiological stress, disease)
20
Q
Cons of ASEXUAL REPRODUCTION
A
- all offspring are clones
- can’t select for favorable traits
21
Q
Cons of SEXUAL REPRODUCTION
A
- requires second type of cell division
- reproductive division from diploid to haploid (meiosis)
- required to locate/select/court/mate with a partner
- dilution of alleles (only 50% related to F1)
- entrust future of female alleles
- high energetic cost
- producing germ cells
- locating/courting partner
- mating
- nourishing and nurturing offspring
- high biological risks
- untested alleles (?)
- predation
- disease
22
Q
Pros of SEXUAL REPRODUCTION
A
- genetic variation between offspring
- 2 genetically dissimilar parents
- diakinesis (recombination of grandparental genes)
- raw material for evolution
- sexual species have highly evolved features
- eg CVS, CNS
23
Q
Which is better - sexual or asexual reproduction?
A
- if the environment is stable –> asexual reproduction is better
- but generally sexual reproduction is better
- CONTEXT DEPENDENT
24
Q
How can a sexually reproducing organism maximize its LRO?
A
- maximize number of reproductive partners (polygamy should be the rule)
- maximize the number of germ cells produced
- maximize the probability of fertilization
- minimize the interval between offspring
- gestation short and quick
- have another baby quickly after the last one
25
Q
Strategy for flowering plants (angiosperms)
A
- multiple partners
- lots of germ cells (pollen)
- fertilization by wind, water, animals
- seasonal production of seeds
- season for producing seeds and season for setting seed
26
Q
Strategy for aquatic invertebrates
A
- multiple partners
- lots of germ cells (eggs and milt)
- fertilization in water “by chance”
- a “numbers game”
27
Q
Strategy for elasmobranchs and teleosts
A
- multiple partners
- lots of germ cells (eggs and milt)
- fertilization in water at spawning grounds (timed external fertilization)
- not random, timed/synchronized, external fertilization
- fertilization can be internal
28
Q
Strategy for amphibia
A
- polygamy
- lots of germ cells (eggs and sperm)
- fertilization in water at spawning
- synchronous external fertilization or
- indirect internal fertilization
- eg salamanders (female walks over sperm, taken up)
29
Q
Strategy for rerrestrial invertebrates
A
- polygamy and monogamy
- lots of germ cells (eggs and sperm)
- fertilization - indirect or direct internal
- spermatophore/intromissive organ
- sperm can’t be left outside on land - dries out
30
Q
Strategy for terrestrial vertebrates
A
- polygamy and monogamy
- fewer germ cells (eggs and sperm)
- fertilization (internal)
31
Q
Purpose of egg
A
- yolk sac for nourishment
- keeps egg sac from drying out
- reproduction needs fluid
32
Q
Reptilian vs Avian eggs
A
- avian eggs = completely impervious to gasses - cracks
- reptile eggs permeate to gas - tears
33
Q
Strategy for mammals
Stages of development
A
- oocyte - female germ cell, haploid (via meiosis)
- zygote - diploid, joining of male and female germ cells, ~ single-celled embryo
- embryo - organogenesis, ball of cells developing
- fetus - once all organs are present (after about 6 weeks in mammals, then just grows)
- infant - newborn
34
Q
When is a mammal born?
A
see different types of mammals
35
Q
Types of mammals
A
- Protheria = monotremes
- Metatheria = marsupials
- Eutheria = placental
36
Q
Protheria
A
- monotremes
- mammals that lay eggs instead of giving birth to live young
- eg echidna, platypus
- lay eggs that stay in the pouch
- leathery eggs - like reptiles
- inside egg = embryo (already fertilized)
- only one with chance to survive without parent
37
Q
Metatheria
A
- contains placental mammals, and others
- living mammals with abdominal pouches
- eg kangaroos, possums, etc
- accommodate neonates in abdominal pouches
38
Q
Eutheria
A
- placental mammals
- give birth to live young
39
Q
Strategy for eutheria
A
- polytocus - producing many offspring in a single birth
- several oocytes to several embryos
- monotocus - producing a single offspring in a single birth
- ~ single embryos
40
Q
Modes of reproduction
Species can be…
A
- oviparous
- viviparous
- ovoviviparous
41
Q
Oviparous
A
- lay eggs
- pre-/post-fertilization
- **nutrition **from egg yolk
- lay eggs with little/no embryonic development within the mother
42
Q
Viviparous
A
- give birth to live young
- **nutrition **from parent
- eg placenta
- development of the embryo inside the body of the mother
43
Q
Ovoviviparous
A
- give birth to ** live young**
- nutrition from egg yolk
- embryos develop inside eggs that are retained within the mother’s body until they are ready to hatch
44
Q
Modes of reproduction
species can be:
A
- r-selected
- K-selected
45
Q
r-selected species
A
- reproduce and develop rapidly
- highly prolific
- eg polytocus
-
little/no parental investment
- eg most insects
46
Q
K-selected species
A
- reproduce a d develop slowly
-
few offpring
- eg monotocus
- **high **level of parental investment
- eg humans
- population may be at carrying capacity
47
Q
What determines LRS?
A
- LRO
- fecundity/fertility of F1
- probability that F1 survive to sexual maturity / achieve fertility
- because this probability is usually less than 1, LRS is always less than LRO
48
Q
What would influence the probability of offspring surviving to sexual maturity?
A
- rate of development
- precocious = fast
- survival
- starvation (most likely)
- predation
- disease
which of these can a parent influence and how?
- rate of development
- fed more = faster development (with genetics too)
- starviation
- bring food/milk
- help avoid predation
49
Q
Reproduction and development are…
A
interdependent
parenting can influence both
50
Q
Balancing investment
A
producing gametes side = aquatic invertebrates (can’t control where sperm/eggs go)
parental care side = mammals
51
Q
A
