week 1 Flashcards by victoria mercier

What is the purpose of reproduction? (3 points)

Parental generation produces offspring, the first filial generation (F1)

Mechanism by which parents generate the first filial generation

F1 generation acts as parents to the second ilial generation (F2)

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Is the purpose of reproduction to produce the F1 or F2 generation? In other words what does evolution care about?

Evolution cares about the F2 generation. Selection pressures act on the second generation, species are not going to evolve unless the F1 survive to produce F2

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What is the word definition of lifetime reproductive output?

Number of offspring being born to a parent or parents (asexual or sexual) in the F1 generation.

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what is the mathematical equation for LRO?

Product of fecundity (Fertility) x fertile life span

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What determines LRO?

Fecundity

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What determines fecundity? (4 p oints)

The number of offspring it produces.

Number of fertile matings (mate density, success in courting, success in mating act)

Fertility of an indv. (number of gametes produced)

Fertility of partner in sexual reproduction

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What is a semelparous species and give an example.

Single episode of reproduction before death.

Pacific salmon

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What is an iteroparous species, and what are the different kinds?

Several rounds of reproduction before they die.

Monogamous or polygynous or polyandrous

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What 2 things determine the fertile life span?

Age at first fertile mating and age at last fertile mating

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The age at the first fertile mating depends on what factors?

How quickly an organism develops. Precocious individuals obtain sexual maturity at an early age.

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Define precocious

Sexual maturity reached at an earlier age than usual

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What is the age of the last fertile mating often determined by? But what are the 2 exceptions

Death. However, elephants and humans exhibit menopause.

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What is the lifetime reproductive success?

The number of offspring born to a parent in the F1 generation and the number of offspring attributable to a grandparent in the F2 generation.

Goes beyond LRO as it is how many genes are passed down to F2.

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Give an example of when the LRS is much lower than the LRO?

In sterile animals such as hybrids like mules. THe F1 generation is produced the mule, but no further generations are produced.

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What determines life time reproductive success? (3 points)

LRO
Fecundity / fertility of F1
Probability that F1 survive to sexual maturity / achieve fertility

The LRS will always be lower than LRO as it is a probability.

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What are the 7 types of asexual reproduction?

Binary fission
Multiple fission
Budding
Fragmentation
Vegetative propagation
Parthenogenesis
Apomixis

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Explain binary fission

One parent cell splits into 2 identical daughter cells.
The parental cell ceases to exist.
Archaea and Eubacteria

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Explain multiple fission

One parent cell replicated nucleus then splits into several identical daughter cells
Patenral cell ceases to exist

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Explain budding

Daughter cell divides from mother cell.
Parent cell still survives (this is how it is differentiated between binary fission).
Yeast and Hydra

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Explain fragmentation

Offspring regenerate from fragments, fissiparity.

Turbellarians, starfish, annelids

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Explain vegetative propagation

Like fragmentation with plants.
Strawberry runners.
Take a fragment of plant and plant it then a new plant grows

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Explain apoximis

Agamospermy in plants
Production of asexual seeds, not needing another plant to pollinate
Dandelions

Explain parthenogenesis

Occurs in animals,
an unfertilised egg becomes an embryo
Seen in many taxa

What are the pros of asexual reproduction? (3 points)

Simple, only requires one type of cell division - mitosis.

Fast, can occur in the absence of partner

Avoids risks intrinsic to sexual reproduction e.g. predation, physiological stress, disease

What is the main con of asexual reproduction?

All offspring are clones, there is no variation and so no evolution. in a changing environment this is disastrous as cannot evolve.

What are the cons of sexual reproduction? (4 points)

Requires reduction division of diploid to haploid (meiosis). Requires organism to locate / select / court / mate with Dilution of alleles - only 50% of alleles passed on High energetic costs

What are the pros of sexual reproduction? (3 points)

Genetic variation (diakinesis and 2 genetically dissimilar parents) Raw material for evolution - can survive changing environemtns More highly evolved features e.g. CNS and CVS

Which is more advantageous sexual or asexual reproduction?

Depends on whether the environment is static or changing.

How does a sexually reproducing organism maximise its lifetime reproductive output? (4 points)

Maximising the number of reproductive partners : polygamy should be the rule Maximise the number of germ cells produced Maximise the probability of fertilisation Minimise the inter birth interval

Explain the strategy for flowering plants - angiosperms (3 points)

Multiple partners Multiple fertilisation mechanisms Seasonal production of germ cells and setting seeds

Explain the strategy for aquatic invertebrates (3 points)

Echinoderms: have multiple partners lots of germ cells (eggs and milt) fertilisation in water (not targeted just by chance)

Explain what sort of process reproduction is

It is a wet process, it needs to take place in water and when it doesn't we need to create water for it to take place in.

Explain the strategy for elasmobranchs and teleosts (4 points)

(sharks and rays) and (bony fish) Multiple partners Lots of germ cells produced (eggs and milt) Fertilisation in water at spawning grounds, it is a targeted process, still external fertilisation but not random Fertilisation can be internal as in sharks with claspers

Explain the strategy for amphibians (3 points)

Polygamy (some sp. monogamous in a season e.g. Lithobates catesbeianus) Lots of germ cells Fertilisation occurs in water at spawning grounds, synchronous internal or external fertilisaion

Explain the strategy for terrestrial invertebrates (3 points)

Polygamy and monogamy lots of germ cells fertilisation can be indirect or direct internal (spermatophore or intromissive organ)

Explain the strategy for terrestrial vertebrates (3 points)

polygamy and monogamy fewer germ cells than other taxa internal fertilisation very varied

What is the purpose of an egg? | What are the differences between the reptilian and avian egg?

Creating a wet environment inside the shell, the embryo wont develop unless it is inside this lake environment. Yolk is for nourishment. Reptilian eggs are leathery and permeable to gases.

What is the main feature that defines a mammal?

mammary glands

What are the 5 stages of development?

``` Oocyte - haploid Zygote - diploid Embryo - many cells Fetus - when all cells are developed (6 weeks in H.sapien) Infant ```

What are the 3 different groups of mammals?

Protheria Metatheria Eutheria

What are protheria?

Ovoviviparous, give birth to eggs but they are retained inside a pouch in their cloaca

What are eutheria?

Give birth to live young, viviparous. Placental nourishment

What are metatheria?

Give birth to a foetus that crawls into a pouch - marsupials

What are the two different strategies for eutheria with regards to number of young?

Polytocus | Monotocus

What is polytocus

release several oocytes that give rise to several embryos. more infants than teats

What is monotocus?

less infants than teats | release one oocyte, rare to ovulate more than one oocyte

What two things would influence the probability of offspring to survive to sexual maturity?

Rate of development | Survival - starvation, predation, disease

There is a balance in investments in reproduction what does this mean?

Selection pressures will drive us to producing lots of gametes or having high parental care but you cannot do both.

What are the two modes of reproduction which species can be defined as?

r selected species | k selected species

Explain r-selected species

Rapid development Highly prolific - lots of offspring little or no parental care

Explain k selected species

Slow developing few offspring - monotocus high level of parental investment

What is the biological basis of the inverse correlation between the number of offspring and the level of parental investment?

Environment is at the carrying capacity, it can only accomodate a limited number of offspring - there are sufficient resources in parent to invest in increased care for young Need to ensure the limited number of offspring you produce survive, under more pressure to invest in paretnal care Resource demands of increased parental care

Generally who does the burden of embryonic and neonate nutrition fall too?

Maternal. Oviparous / ovoviviparous - maternal proteins and lipids invested in egg yolk. Viviparous - placenta. Neonate - mammary glands. Lactogenesis and lactattion Post weaning nutrition - mother and lion cubs example