MODULE 5: HEREDITY Flashcards
INQ 1.1
Sexual Reproduction
The fusion of a gamete (sperm and egg) from both parents to produce a genetically unique offspring.
INQ 1.1
Asexual Reproduction
Reproduction requiring only one parent and produces an offspring that is genetically identical to a single parent (unless mutations occur).
INQ 1.1
Internal Fertilisation
The fertilisation of an egg and a sperm inside the body of a female.
- male transferring his gamete (sperm) into directly inside a female’s reproductive tract to fertilise her gamete (egg)
INQ 1.1
Continuity of Species
The ability of a species to persist over time through reproduction, ensuring that genetic information is passed on to subsequent generations.
INQ 1.1
External Fertilisation
A male depositing his sperm on a female gamete (egg) outside of the female’s body.
INQ 1.1
How does sexual reproduction ensure the continuity of a species?
- The combination of chromosomes from two organisms increases genetic variability
- This assists with a species survival, as it allows for them to be able to adapt to changing environments
INQ 1.1
Advantages of External Fertilisation
- a large number of gametes is dispersed at a time = higher number of offsprings produced - increased genetic variation
- No need to find a mate - easier fertilisation process and time efficient
- usually more rapid and prolific
- no energy is needed for gestation and caring for young
- as the young is widely dispersed, compeitition is reduced with the parent and each other
INQ 1.1
Advantages of Internal Fertilisation
- increased liklihood of fertilisation as the two gametes are in close proximity to each other.
- increased protection of offspring from the outside environment = increased survival rate
- Protects the gametes from being dehydrated on land
- Developed young is taken cared for and fed, increasing chances of survival
- gametes and zygote is protected from predation and diseases.
INQ 1.1
Disadvantages of External Fertilisation
- recquires an aquatic environment
- no protection is given to the eggs (vulnerbale to predators)
- large number of gametes = takes time and energy
- no control on how many gametes released
- decreased chance of successful fertilisation
- young needs to fend for themselves
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Disadvantages of Internal Fertilisation
- longer gestation period
- time and energy is needed to care for young after birth
- potential for STIs
- energetically costly for both parents
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How do plants reproduce?
- Sexual reproduction: pollination (transfer of pollen from anther to stigma of plant)
- Asexual reproduction: vegetative propagation (bulb, rhizome, runners, sucker, tuber)
INQ 1.1
Advantages of Sexual Reproduction
- fertilisation is less risky (controlled env. and protection); young are more likely to survive
- unfavourable genetic traits can be eliminated
- more genetic diversity
- able to adapt to changing environments
- improves the evolutionary potential of populations
this all allows for the continuity of species
INQ 1.1
Disadvantages of Sexual Reproduction
- slower reproductive rate
- mates need to be found and accepted
- recombination during meiosis can introduce deletarious variation
- potential for STIs
- energetically costly
INQ 1.1
Advantages of Asexual Reproduction
- energy efficient (no mate)
- passing on of favourable traits
- fast rate of reproduction
– rapid rate of repopulation
– short gestation period
– good if selection pressure is posed and species need to repopulation before extinction
INQ 1.1
Disadvantages of Asexual Reproduction
- little to no genetic variation
– risk of extinction if selection pressure is posed - faster rate of repopulation
– increases compeition (decreases population of other species in the food web)