11.2: Asexual Reproduction - Plants and Animals

fission

parent cell or organism separates itself into 2 equally-sized daughter cells/organisms. Found in all kingdoms and domains but most common in bacteria, archaea and Protista

binary fission

when parent produces 2 equally sized offspring. in bacteria and archaea. Involves initial enlargement of parent cell and a duplication of nucleus before division

multiple fission

reproduction resulting in numerous offspring. more common in Protista. fast and initially occurs via division of nucleus into many parts then cytoplasm forms around these nucleus and organism separates

budding

in all domains and kingdoms. Small outgrowth from parent breaks off to form new smaller daughter. Different from fission as budding results into 2 unequal parts

fragmentation

parent breaks into fragments, each capable of growing independently into a new organism. Each fragmentation develop mature and fully grown individuals identical to parent in respect to shape, size, etc. e.g starfish

is fragmentation always intentional

No. can be intentional and unintentional

vegetative propagation

similar to fragmentation as a full organism can form the fragment of its parent. voluntarily or involuntarily. only in plants. Involves movement of offspring away from parent = pop persistence while reducing competition

parthogenesis

occurs in multicellular plants and animals. Development of offspring from an unfertilised or self-fertilised gamete. Often occurs in organisms also capable of sexual reproduction.

parthenogenesis example

• aphid females reproduce via parthenogenesis and are viviparous when its summer with high temps and abundant food. Mates with male when temp declines and switch to oviparous

• in honey bees, ants and wasps, parthen. part of mechanism that determines sex. Males develop from unfertilised egg and haploid. females develop from fertilised and are diploid

apomixis

production of seeds without pollinator or fertilisation e.g. dandelions

artificial methods of asexual reproduction

• grafting - upper portion (scion) of 1 plant is combined with lower portion (rootstock) of another plant forming graft

• cutting

• layering

• micropropagation

List an advantage of fragmentation that is not related to reproduction

allows an organism to regenerate lost or damaged body parts, which aids in survival and recovery after injury.

Describe the similarities between budding and fragmentation that differ from parthenogenesis

budding and fragmentation = asexual methods, involve producing new individual from part of parent and don’t require gametes/fertilisation.

Parthen = from unfertilised eggs not piece of parent’s body and new individual develops from a gamete rather than somatic tissue

Explain the advantages and disadvantages of asexual reproduction in plants

A = rapid pop increase in stable enviro, no need for mate saving energy and preserves successful genotypes that are well-adapted

D = lack genetic variation, limited adaptability and spread of harmful mutations