9/22/2015 CHAPTER 25 PLANTS

9/22/2015 PLANTS Most are autotrophic organisms Most are autotrophic organisms Provide food for themselves and the world Provide food for themselves and the world Have chlorophyll for photosynthesis Have chlorophyll for photosynthesis Found in most environments Found in most environments oceans, fresh water, polar regions, land, and desert conditions oceans, fresh water, polar regions, land, and desert conditions

9/22/2015 PLANTS 3 Common characteristics: 3 Common characteristics: Anchored to soil, rock, bark, and other solid objects Anchored to soil, rock, bark, and other solid objects Have hard, woody tissue for support to allow them to stand upright Have hard, woody tissue for support to allow them to stand upright Have chlorophyll (green) and are able to photosynthesize Have chlorophyll (green) and are able to photosynthesize Botany - The branch of biology that studies plants Botany - The branch of biology that studies plants

9/22/2015 ALTERNATION OF GENERATIONS Live alternatively between two different forms during their life cycle. Live alternatively between two different forms during their life cycle. One stage is diploid (2n) – sporophyte One stage is diploid (2n) – sporophyte The other stage is haploid (n) – gametophyte The other stage is haploid (n) – gametophyte During sporophyte stage, cells undergo meiosis to produce spores (haploid) During sporophyte stage, cells undergo meiosis to produce spores (haploid) Spores then germinate into the gametophyte (haploid) through mitosis Spores then germinate into the gametophyte (haploid) through mitosis Produces the male and female gametes Produces the male and female gametes Gametes fuse to form zygotes (diploid) Gametes fuse to form zygotes (diploid) Mitosis produces the sporophyte (diploid) Mitosis produces the sporophyte (diploid)

9/22/2015 ALTERNATION OF GENERATIONS

9/22/2015 PLANTS Four major groups: Four major groups: Bryophytes – mosses Bryophytes – mosses Seedless vascular – horsetails, ferns Seedless vascular – horsetails, ferns Gymnosperms – evergreens, ginkgos Gymnosperms – evergreens, ginkgos Angiosperms – flowering plants Angiosperms – flowering plants

9/22/2015 BRYOPHYTES Small, slow growing plants Small, slow growing plants Produce motile sperm Produce motile sperm Nonvascular (no roots, stems or leaves) Nonvascular (no roots, stems or leaves) Obtain nutrients from where they grow or from rain Obtain nutrients from where they grow or from rain Three types : Three types : mosses mosses liverworts liverworts hornworts hornworts

9/22/2015 BRYOPHYTES Mosses grow as a carpet and have leaf-like structures for photosynthesis Mosses grow as a carpet and have leaf-like structures for photosynthesis Liverworts and hornworts are small, low growing plants composed of a green ribbon of cells. Liverworts and hornworts are small, low growing plants composed of a green ribbon of cells. Gametophyte generation is most dominant Gametophyte generation is most dominant

9/22/2015 ADAPTATIONS TO LAND: VASCULAR TISSUE Designed to move water and nutrients within plants Designed to move water and nutrients within plants Found in roots, stems, and leaves Found in roots, stems, and leaves Two kinds: Two kinds: Xylem —transports water from roots Xylem —transports water from roots Phloem —transports nutrients (food) from leaves Phloem —transports nutrients (food) from leaves

9/22/2015 ROOTS May be fibrous or tap roots May be fibrous or tap roots Also used to store food Also used to store food carrots, turnips, radishes carrots, turnips, radishes Have root hairs that increase the surface area for absorption of nutrients. Have root hairs that increase the surface area for absorption of nutrients.

9/22/2015 STEMS Most are above ground Most are above ground Many have buds which may grow to be leaves, flowers, or new branches Many have buds which may grow to be leaves, flowers, or new branches Function of stems: Function of stems: support leaves support leaves Transport materials from roots to leaves Transport materials from roots to leaves Transport food from leaves to roots Transport food from leaves to roots

9/22/2015 LEAVES The sites of photosynthesis The sites of photosynthesis Characterized by: Characterized by: Cells have chloroplasts Cells have chloroplasts Have a waxy coating (cuticle) to help avoid water loss Have a waxy coating (cuticle) to help avoid water loss Have vascular tissue Have vascular tissue Openings known as stomata control movement of CO2, oxygen, and water Openings known as stomata control movement of CO2, oxygen, and water

9/22/2015 LEAVES

SEEDLESS VASCULAR Includes ferns, horsetails, and club mosses Includes ferns, horsetails, and club mosses Produce diploid and haploid spores Produce diploid and haploid spores Fertilization results in multi-cellular embryo Fertilization results in multi-cellular embryo Sporophyte generation is more dominant Sporophyte generation is more dominant Have well developed vascular tissue Have well developed vascular tissue

9/22/2015 GYMNOSPERMS Seed-producing plants Seed-producing plants A seed contains: A seed contains: An embryo An embryo Protective seed coat Protective seed coat Stored food for the embryo Stored food for the embryo Produce cones for reproduction (both male and female) Produce cones for reproduction (both male and female) Includes evergreens and ginkgos Includes evergreens and ginkgos

9/22/2015 GYMNOSPERMS Technically means “naked seeds” Technically means “naked seeds” Vulnerable to environmental conditions Vulnerable to environmental conditions Many have needle-shaped leaves that fall periodically throughout the year (not all at the same time) Many have needle-shaped leaves that fall periodically throughout the year (not all at the same time) Known as perennials – get taller and larger year after year Known as perennials – get taller and larger year after year

9/22/2015 ANGIOSPERMS Seeds are protected by the ovary Seeds are protected by the ovary matures into a fruit matures into a fruit Many foods we eat are fruits containing seeds of angiosperms: Many foods we eat are fruits containing seeds of angiosperms: green beans, melons, tomatoes, and apples green beans, melons, tomatoes, and apples

9/22/2015 ANGIOSPERMS Most have broad leaves which they may lose during the fall (cooler regions) Most have broad leaves which they may lose during the fall (cooler regions) Deciduous trees Deciduous trees Some keep their leaves all winter Some keep their leaves all winter American holly Ilex opaca American holly Ilex opaca Most are small plants, grasses, wildflowers, and house plants Most are small plants, grasses, wildflowers, and house plants

9/22/2015 ANGIOSPERMS Flower produce gametes Flower produce gametes Pistil – female reproductive organs Pistil – female reproductive organs Style, stigma, ovary Style, stigma, ovary Stamen – male reproductive organs Stamen – male reproductive organs Anthers, filaments Anthers, filaments Sepals – outermost protective structures Sepals – outermost protective structures Petals – accessory organs for fertilization Petals – accessory organs for fertilization If a flower has both male and female parts, it is called a perfect flower. If a flower has both male and female parts, it is called a perfect flower. If just one part – imperfect flower If just one part – imperfect flower Flowers are used to attract insects for pollination. Flowers are used to attract insects for pollination.

9/22/2015 PERFECT FLOWER

9/22/2015 ANGIOSPERMS Divided into two categories: Divided into two categories: Monocots and dicots Monocots and dicots Monocots have: Monocots have: One-part seed (monocotyledon) – corn One-part seed (monocotyledon) – corn Parallel veins on leaves Parallel veins on leaves Vascular tissue arranged in scattered bundles Vascular tissue arranged in scattered bundles Dicots have: Dicots have: Two-part seed (dicotyledons) – beans Two-part seed (dicotyledons) – beans Net-like vein pattern on leaves Net-like vein pattern on leaves Vascular tissue arranged in rings Vascular tissue arranged in rings

9/22/2015 DICOTS AND MONOCOTS

9/22/2015 TROPISM Reaction of a plant to a stimulus Reaction of a plant to a stimulus Light Light Water Water Plants release a hormone (auxin) in response to the direction of a light source Plants release a hormone (auxin) in response to the direction of a light source Phototropism Phototropism Some hormones also control changes in their growth and development Some hormones also control changes in their growth and development Based on day length Based on day length Some produce flowers only on long days, others on short days Some produce flowers only on long days, others on short days

9/22/2015 CHAPTER 25 PLANTS

9/22/2015