Plant Reproduction Angiosperms, mosses, and ferns

Plant reproduction  Plants use both asexual (one) and sexual (two) reproduction to pass their genes onto the next generation.

Plant reproduction  Plants use both asexual (one) and sexual (two) reproduction to pass their genes onto the next generation.  Lower plants – sexual repro. produces spores from meiosis

Plant reproduction  Plants use both asexual (one) and sexual (two) reproduction to pass their genes onto the next generation.  Lower plants – sexual repro. produces spores from meiosis  Higher plants – gametes fuse to form a zygote which develops into an embryo inside a seed.

Plant reproduction  Plants use both asexual (one) and sexual (two) reproduction to pass their genes onto the next generation.  Lower plants – sexual repro. produces spores from meiosis  Higher plants – gametes fuse to form a zygote which develops into an embryo inside a seed.  g5GIw g5GIw

Plant reproduction  Plants use both asexual (one) and sexual (two) reproduction to pass their genes onto the next generation.  Lower plants – sexual repro. produces spores from meiosis  Higher plants – gametes fuse to form a zygote which develops into an embryo inside a seed.  g5GIw g5GIw  Coc Coc

Plant reproduction  Seeds are dispersed by

Plant reproduction  Seeds are dispersed by  jWl3AOM jWl3AOM

Plant reproduction  Seeds are dispersed by birds and wind etc to a range of habitats.

Plant reproduction  Seeds are dispersed by birds and wind etc to a range of habitats.  Some habitats may be suitable for the germination of the seed, but some may not – this results in large losses of seeds and genes from those parent plants.

Plant reproduction  Seeds are dispersed by birds and wind etc to a range of habitats.  Some habitats may be suitable for the germination of the seed, but some may not – this results in large losses of seeds and genes from those parent plants.  Some seeds will tolerate the habitat because it is similar to the one their parents were in.

Plant reproduction  Asexual plants produce offspring by mitotic cell division – all offspring are genetically identical to their parent.

Plant reproduction  Asexual plants produce offspring by mitotic cell division – all offspring are genetically identical to their parent.  Eg  Strawberries produce horizontal stems called runners.

Plant reproduction  Asexual plants produce offspring by mitotic cell division – all offspring are genetically identical to their parent.  Eg  Strawberries produce horizontal stems called runners.  Eg  daffodils and onions produce bulbs underground.

Plant reproduction  Conditions are usually ideal for the new plants growing through asexual reproduction.

Plant reproduction  Conditions are usually ideal for the new plants growing through asexual reproduction.  This can cause problems because of the dense population of the plant. Eg  old man’s beard.

Plant reproduction  Conditions are usually ideal for the new plants growing through asexual reproduction.  This can cause problems because of the dense population of the plant. Eg  old man’s beard.  However, colonising new habitats is difficult for asexual reproducers because there is no dispersal mechanism.

Alternation of generations  Where a diploid (double set of chromosomes) asexual generation is followed by a haploid (one set of chromosomes) sexual generation.

Alternation of generations  Where a diploid (double set of chromosomes) asexual generation is followed by a haploid (one set of chromosomes) sexual generation.  Gametes from gametophytes fuse to form a zygote, which grows into a sporophyte.

Alternation of generations  Where a diploid (double set of chromosomes) asexual generation is followed by a haploid (one set of chromosomes) sexual generation.  Gametes from gametophytes fuse to form a zygote, which grows into a sporophyte.  Sporophytes produce haploid spores from meiosis which grow into gametophytes.

Alternation of generations  Sporophytes contain double the genetic info as gametophytes and also produce spores which are genetically unique, so the trend in plant evolution has to be; increase the size and development of the sporophyte at the gametophyte’s expense.

Mosses  Spores produced by the sporophyte are resistant to drying out, and are blown until they settle and germinate into gametophytes.

Mosses  Spores produced by the sporophyte are resistant to drying out, and are blown until they settle and germinate into gametophytes.  Gametophyte is the dominant generation, being larger and with a longer lifespan than that of the sporophyte.  mm-QE mm-QE

Mosses  Spores produced by the sporophyte are resistant to drying out, and are blown until they settle and germinate into gametophytes.  Gametophyte is the dominant generation, being larger and with a longer lifespan than that of the sporophyte.  Gametophytes produce sperm from a male gametangium and eggs from the female gametangium.

Mosses  Spores produced by the sporophyte are resistant to drying out, and are blown until they settle and germinate into gametophytes.  Gametophyte is the dominant generation, being larger and with a longer lifespan than that of the sporophyte.  Gametophytes produce sperm from a male gametangium and eggs from the female gametangium.  Reproduction requires water, because sperm must swim to an egg for fertilisation to occur.

Ferns  The sporophyte is the dominant generation.

Ferns  The sporophyte is the dominant generation.  Fern spores are produced on the underside of fronds and germinate in damp conditions into very small heart- shaped gametophytes.

Ferns  The sporophyte is the dominant generation.  Fern spores are produced on the underside of fronds and germinate in damp conditions into very small heart- shaped gametophytes.  Gametophytes survive for just a few weeks. Sperm need water to swim to the egg of a nearby female.

Ferns  The sporophyte is the dominant generation.  Fern spores are produced on the underside of fronds and germinate in damp conditions into very small heart-shaped gametophytes.  Gametophytes survive for just a few weeks. Sperm need water to swim to the egg of a nearby female.  The sporophyte formed after fertilisation draws nourishment from the gametophyte only until the sporophyte begins to photosynthesis.

Ferns  The sporophyte is the dominant generation.  Fern spores are produced on the underside of fronds and germinate in damp conditions into very small heart-shaped gametophytes.  Gametophytes survive for just a few weeks. Sperm need water to swim to the egg of a nearby female.  The sporophyte formed after fertilisation draws nourishment from the gametophyte only until the sporophyte begins to photosynthesis.  The fern sporophyte is well adapted to the land environment. Ferns – the ponga and silver fern have evolved to colonise a number of habitats even though they still require water for reproduction.

Ferns  DWt678 DWt678

Questions 1. A plant reproduced asexually for two generations. What must be assumed about the chromosome number of the second generation?