Adaptasi Tumbuhan pada Lingkungan Habitat Lahan Kering Bahan Kajian MK. Agroekologi...

Adaptasi Tumbuhan pada

Lingkungan Habitat Lahan Kering

Bahan Kajian MK. Agroekologi

Smno.jurstnh.fpub.2013

Apakah Tumbuhan itu?

• Multicellular organism that performs photosynthesis and develops from an embryo

• Almost all live on land• Descendants of protists• Land invasion depended on evolution of

different structures

Copyright 2005—Brooks/Cole—Thomson Learning

Adaptasi Lahan-Darat

• Waxy cuticle — reduces water loss• Ability to absorb water from a variety of

sources• Enclosed reproductive organs, called

gametangia, in which gametes form• Enclosed sporangia in which spores form

Identifikasi beragam Tipe Tumbuhan

• Identify as many different plants as you can. How are they different from one another?

Vaskuler vs. Non-vaskuler

• Vascular or tracheophytes

• Have pipelike tissues that conduct water

• Grow large• Examples: fir trees,

ferns

• Nonvascular or bryophytes

• Lack a vascular system

• Much smaller• Less diverse

Divisio Tumbuhan

Copyright 2005—Brooks/Cole—Thomson Learning

Evolusi Tumbuhan

Copyright 2005—Brooks/Cole—Thomson Learning

1. Evidence comes from fossils and comparisons with living species

2. First plants evolved from a common ancestor that resembled a green alga

3. Vascular plants predate nonvascular plants4. First seedless plants — Carboniferous Period

Evolusi Tumbuhan

Kingdom Plantae

Copyright 2005—Brooks/Cole—Thomson Learning

Evolusi Angiospermae

• Angiosperms — flowering plants• First fossils — about 125 million years ago• Evolved from gymnosperms — plants that have

no fruits or flowers• Many adaptations

Mosses, Liverworts and Hornworts• Nonvascular Plants or

bryophytes• Depend on free

standing water for photosynthesis and fertilization

Copyright 2005—Brooks/Cole—Thomson Learning

Karakteristik Bryophyta

• All parts of their bodies are adapted to absorb water

• This gives them a spongy feel• Exhibit alternation of generations — a sexual

life cycle in which haploid and diploid phases are both multicellular

Siklus Hidup Lumut (Moss)

Copyright 2005—Brooks/Cole—Thomson Learning

Tumbuhan Berpembuluh (Vaskuler)

Copyright 2005—Brooks/Cole—Thomson Learning

• Called tracheophytes• Have division of labor with separate transport

systems for water (xylem) and sugars (phloem)• Diploid Phase dominates the life of the plant• Seeds are protected by coat, and food is stored

inside for germination

Tumbuhan Berpembuluh (Vaskuler)

Seed-Lacking Tracheophytes

• 4 divisions that lack seeds:– Pterophytes (ferns)– Psilotophytes– Lycophytes– Equisetophytes

Siklus Hidup Paku-pakuan

Copyright 2005—Brooks/Cole—Thomson Learning

• A fern releases haploid spores• Spores mature into haploid gametophytes• Gametophytes make sperm and egg• Fusion of sperm and egg• Zygotes grow right out of the gametophyte for

a new fern

Siklus Hidup Paku-pakuan

Lycophytes

• Have true roots, stems and simple leaves

• Also called lycopods

• Example: club mosses

Copyright 2005—Brooks/Cole—Thomson Learning

Equisetophytes

• Referred to as horsetails

• Have true roots, stems and complex leaves

• Stems are jointed• Outer cell walls are

reinforced with silica

Copyright 2005—Brooks/Cole—Thomson Learning

Reproduksi Tumbuhan Berbiji

• Manage fertilization without water• Use a form of internal fertilization• Sperm and ovum fused, and develop within

the female gametophyte• Seeds consist of a diploid zygote and a source

of food encased in a seed coat

Gymnosperms

1. Seed plants without flowers2. Evergreen3. Conifers produce male and female

gametophytes in cone-shaped strobili (the cones)

4. Male and female cones on same tree

Siklus Hidup Pinus

Copyright 2005—Brooks/Cole—Thomson Learning

Cycads

1. Large-leafed plants that look like palms

2. No flowers or fruits

3. Bear naked seeds

4. Produce male and female strobili

Copyright 2005—Brooks/Cole—Thomson Learning

Kegunaan Bunga dan Buah

• Flowers ensure distribution of pollen through a variety of methods

• Fruits are mature ovaries that enclose and protect seeds

• Fruits usually enhance dispersal of seeds

Siklus Hidup Tumbuhan Berbunga

Copyright 2005—Brooks/Cole—Thomson Learning

Reproduksi Angiospermae

• Flowers reproduce by means of double fertilization

• 2 sperm nuclei from the pollen grain fertilize 2 ova from the ovary

• A diploid zygote is formed and a triploid cell forms the endosperm

Bagian-bagian Bunga

• Stamen — anther and filament (male)• Carpel — style and ovary (female)• A corolla or petals and a calyx of sepals

surround stamens and carpels• Not all flowers have all parts

Konsep-konsep Kunci

• A plant is a multicellular organism that photosynthesizes and develops an embryo

• Nonvascular plants lack vascular tissues• The vascular system enables plants to transport

water and nutrients, to grow large, and to diversify

• Seeds allow plant to withstand dry environments