Reproduction Flashcards
Why is reproduction important?
- without reproduction=no heredity+no evolution
- evolutionary advantage as spreads genetic material
- successful individual has no use without reproduction
What are the advantages and disadvantages of producing small number of offspring?
Advantages:
- many species who have small no. Of young will care and raise them thus more likely to survive until sexual maturity
Disadvantages:
- takes a lot of energy
-Life is short because energy is spent on getting genetic material into next generation
What are the advantages and disadvantages of producing many offspring?
Advantages:
- more offspring means larger population so more species and genetic material
- doesn’t use as much energy as don’t have to raise offspring
Disadvantages:
- uses lots of energy still
- many offspring die before sexual maturity
What is fertilisation?
The fusion of male and female gametes and requires water body to occur so gametes and zygotes don’t dry out e.g ocean, lake or internal water of parents body
What are the advantages and disadvantages of external fertilisation?
Advantages:
Syngamy occurs in external medium, organisms have great synchrony between sexes, large no. Of gametes released to increase chances of syngamy
Disadvantages:
offspring are vulnerable to predators threatening survival to adults
E.g. algae, fish, amphibians
What are the advantages of internal fertilisation?
Advantages:
Syngamy occurs inside body, an egg is formed in female body, the male gamete is motile, no. Of sperms produced is very large but no increase in eggs produced, vulnerability decreases
E.g. fungi, reptiles, mammals, birds
What is syngamy?
Gamatic fusion
What does motile mean?
Capable of motion
What is pollination?
The process required by plants for sexual reproduction
angiosperms and gymnosperms reproduces this way using internal fertilisation and sperm contained in pollen grain
This is an effective fertilisation method but requires large amount of energy to make large no. Of gametes required.
What is seed dispersal?
Most angiosperms and conifers disperse seeds after fertilisation they do this in numerous ways including wind, attaching to animals etc.
What is an angiosperm?
A flowering plant
What is a conifer?
A gymnosperm which is a cone bearing seed plant (produces woody flowers)
What is asexual reproduction?
The production of identical offspring from 1 parent.
The simplest way organisms reproduce.
Uses mitosis
Only way offspring can be genetically different is from mutations
What are the characteristics of asexual reproduction?
- occurs in unicellular organisms
- large no. Of individuals produced quickly
- advantaged in unchanging environments where organisms are adapted
- lack of genetic variation
- unfavourable conditions make all species vulnerable and may lead to extinction
What is binary fission?
Equal division of parent cell into new cells. E.g bacteria and protozoan
What is budding?
Division of cytoplasm is unequal and new organisms grow on plant before eating e.g. yeasts, hydra, protists
What is fragmentation?
Part of an organism breaks off and regenerates into a new individual e.g. flatworms, Marine worms, echinoderms
What is spore formation?
Spores release into environment germinate into new individuals e.g. fungi, flowering plants
What is vegetative propagation?
Plant seperate to form new plant from leaves, stems and underground stems e.g. many flowering plants
What is parthenogenesis?
Type of cloning from formation of new individual from unfertilised egg, all offspring are clones of a female parent
(No males are produced) e.g. insects, lizards and birds
What are common features of mammals?
- warm-blooded
- nourish their offspring with milk
- have hair or fur
- reproduce sexually using internal fertilisation
E.g. humans, dogs and whales
What are the characteristics of placental mammals?
- Embryo grows inside uterus
- placenta allows nutrients and oxygen to be supplied and waste to be removed via mothers blood
- pregnancies are longer and offspring are more developed when born
What are the characteristics of marsupials?
- Have placenta to support internal embryonic development
- give birth to tiny, partially developed offspring that continue to develop after birth
E.g. kangaroos and quolls
What are characteristics of monotremes?
- lay soft eggs from which a small puggle emerges and continues to grow supported by mothers milk
E.g. platypus and echidna
Rarest mammal
Why does the umbilical cord need to have a two way transport?
it needs to transport nutrients to the baby and waste from the baby
Where are follicles located?
Inside the ovaries
What hormone do follicles release into the bloodstream?
Oestrogen