Kingdom Fungi - Biologi kelas 10 SMA

Introduction to Kingdom Fungi

Overview of the Topic

• Kak Hera introduces the topic of fungi, specifically focusing on the characteristics, structure, lifestyle, habitat, classification, and symbiosis of fungi.

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Characteristics of Fungi

Key Features

• Fungi do not possess chlorophyll, distinguishing them from plants; they were initially classified under Plantae but were later separated into their own kingdom due to significant differences.

• Fungi can be unicellular (single-celled) or multicellular (many-celled), showcasing a variety of forms such as mushrooms and molds.

• They are eukaryotic organisms with a cell membrane nucleus and have bodies composed of hyphae (filaments).

• The cell walls of fungi contain chitin, differing from plant cell walls which are made up of cellulose.

Structure of Fungi

Hyphal Structure

• Hyphae can be categorized into septate (with partitions between cells) and coenocytic (without partitions). The latter is characteristic of certain parasitic fungi.

• Parasitic fungi develop specialized structures called haustoria that penetrate host cells to absorb nutrients. An example includes parasitic fungi affecting plant cells.

Lifestyle and Nutrition

Modes of Nutrition

• Fungi are heterotrophic organisms that obtain nutrients by absorbing organic matter from their environment. They are classified based on their nutritional strategies: saprophytic, parasitic, or mutualistic/symbiotic.

Types:

1. Saprofitic: Decomposers that break down dead organic material; examples include fungi found in decaying wood or food waste.

2. Parasitic: Absorb nutrients from living hosts; some cause diseases in their hosts like skin infections in humans caused by certain fungi.

3. Mutualistic/Symbiotic: Form beneficial relationships with other organisms; examples include lichens and mycorrhizae which provide benefits to both partners involved in the symbiosis.

Habitat Diversity

Environmental Adaptations

• Saprophytic fungi thrive in moist environments rich in organic matter; optimal conditions include slightly acidic soil for effective decomposition processes.

• Mutualistic fungi like lichens can survive extreme habitats such as polar regions or deserts due to their adaptability to harsh conditions while forming partnerships with algae or cyanobacteria for nutrition.

Classification of Fungi

Major Groups

1. Zygomycota: Multicellular with coenocytic hyphae lacking septa; unique among fungal groups for this characteristic.

2. Ascomycota: Known for producing spores within sac-like structures called asci.

3. Basidiomycota: Characterized by spore production on club-shaped structures known as basidia.

4. Deuteromycota: Also referred to as "imperfect" fungi due to lack of observed sexual reproduction stages.

Key Characteristics:

• Zygomycota is noted for its non-septate hyphae which sets it apart from other fungal classifications that typically feature septate hyphae alongside reproductive methods involving spore formation through various means including sexual reproduction processes like zygospores formation in Zygomycota itself.[( t = 398 s)]

Zygomycota and Ascomycota: Reproductive Strategies

Characteristics of Zygomycota

• Zygomycota reproduce sexually through the formation of zygospores, characterized by their lack of fruiting bodies. Their structure includes sporangium (spore box) where spores are stored.

• The stolon acts as a rhizoid for nutrient absorption, while rhizoids anchor the fungus. Sporangiofor is the stalk that supports the sporangium.

• Zygomycota typically live as saprophytes, decomposing organic matter such as spoiled food (e.g., bread) or animal waste.

Sexual Reproduction in Zygomycota

• Sexual reproduction begins with positive and negative hyphae coming together to form gametangia, which produce gametes.

• Plasmogamy occurs when cytoplasms fuse, forming zygosporangium with thick walls for environmental resilience.

• Karyogamy follows plasmogamy, resulting in diploid nuclei that undergo meiosis to produce haploid zygospores.

Asexual Reproduction in Zygomycota

• Haploid zygospores germinate into new hyphae and develop into fungi that produce sporangiospores.

• Sporangiospores can break apart to form new hyphae without sexual reproduction.

Examples of Zygomycota

• Notable examples include Rhizopus oryzae (used in tempeh production), Mucor mucedo (found on decaying food), and Pilobolus (grows on horse dung).

Ascomycota: Key Features and Reproductive Methods

Characteristics of Ascomycota

• Ascomycota can be unicellular or multicellular with septate hyphae; they differ from Zygomycota which have non-septate hyphae.

• They exhibit diverse fruiting body forms called ascocarps including apothecium (cup-shaped), perithecium (bottle-shaped), cleistothecium (ball-shaped), or none at all.

Reproductive Strategies in Ascomycota

Sexual Reproduction

• Similar to Zygomycota, sexual reproduction involves fusion of compatible hyphae forming ascogonium and antheridium structures for gamete production.

Plasmogamy Process

• Ascogonium develops connections known as trichogyne facilitating plasmogamy between the two types of hyphae.

This structured approach provides a clear overview of both fungal groups' characteristics and reproductive strategies while linking back to specific timestamps for further exploration.

Fungal Reproduction and Ascomycota Characteristics

Dikaryotic Stage in Fungi

• The anteridium transfers its haploid nucleus to the ascogonium, resulting in a dikaryotic cell that contains two nuclei.

• The ascogonium develops into a branched hyphae structure called hifadikariotik, which eventually forms an ascocarp (fruiting body).

• At the tips of the hyphae within the ascocarp, dikaryotic asci are formed, where karyogamy occurs leading to diploid nuclei.

Meiosis and Spore Formation

• The diploid nuclei undergo meiosis, producing four haploid nuclei from one diploid nucleus.

• These haploid nuclei then divide mitotically, resulting in eight ascospores within a mature ascus.

Asexual Reproduction Mechanisms

• Asexual reproduction can occur through hyphal fragmentation or by forming conidiospores on conidiophores.

• Conidia are released when disturbed (e.g., by wind), allowing them to germinate into new haploid hyphae.

Examples and Roles of Ascomycota

Notable Ascomycota Species

• Aspergillus Wenti: Used in soy sauce production.

• Saccharomyces cerevisiae: Important for making bread, wine, and other fermented products.

• Penicillium notatum: Source of antibiotics; some species also used for cheese flavoring.

Other Significant Fungi

• Tuber melanosporum: Known as truffles; forms symbiotic relationships with plant roots (mycorrhiza).

• Claviceps purpurea: Parasitic fungus affecting wheat; causes ergotism with symptoms like seizures and hallucinations.

Characteristics of Basidiomycota

Structural Features

• Basidiomycota are multicellular fungi with septate hyphae.

• They produce fruiting bodies known as basidiocarps characterized by structures such as caps (pileus), gills (lamellae), and stalk (stipe).

Reproductive Structures

• Basidiospores are produced sexually within basidia located on gills.

Reproductive Processes in Basidiomycota

Sexual Reproduction Steps

• Begins with positive and negative hyphae coming together for plasmogamy, forming dikaryotic mycelium without nuclear fusion initially.

Development of Fruiting Bodies

• Environmental changes trigger the growth of dikaryotic mycelium into fruiting bodies containing basidia that will undergo karyogamy to form diploid cells.

Fungi Reproduction and Types

Basidiomycota Overview

• Basidiomycota undergoes a reproductive process resulting in four haploid nuclei, forming structures called sterigma.

• Each basidium produces a protrusion known as sterigma, where haploid nuclei develop into basidiospores that eventually release into the air to germinate into new hyphae.

Examples of Basidiomycota

• Common edible fungi from this group include:

• Auricularia polytrichia (ear mushroom)

• Volvariella volvacea (straw mushroom)

• Pleurotus ostreatus (oyster mushroom)

• Lentinula edodes (shiitake mushroom)

• Notably, some species like Ustilago graminis are parasitic on crops such as sugarcane, corn, and wheat.

Deuteromycota Characteristics

• Deuteromycota, also known as "imperfect fungi," lack a known sexual reproduction method.

• This group primarily consists of unicellular organisms with septate hyphae and is mostly parasitic.

Pathogenic Examples of Deuteromycota

• Key examples include:

• Epidermophyton floccosum: causes athlete's foot (Tinea pedis).

• Microsporum canis: responsible for ringworm in dogs.

• Malassezia furfur: leads to tinea versicolor.

Symbiosis in Fungi

Mutualistic Relationships

Lichens

• Lichens represent a mutualistic relationship between fungi and algae or cyanobacteria.

• The fungus provides organic nutrients while the algae offer protection and photosynthetic products.

• Lichens thrive in extreme environments like polar regions and rocky surfaces; they reproduce both sexually and asexually through fragmentation or spore production.

Types of Lichens

• Four main types of lichens include:

• Crustose: crust-like appearance tightly attached to substrates.

• Foliose: leaf-like structure with lobed edges.

• Fruticose: bushy form resembling small shrubs or branches.

• Squamulose: scaly texture bridging crustose and foliose forms.

Benefits of Lichens

• They serve as bioindicators for air pollution due to their sensitivity to toxins; their presence indicates clean air quality.

• Additionally, lichens are used in traditional medicine, paper production, act as pioneer species in ecological succession, and contribute to soil fertility.

Mycorrhizal Associations

Types of Mycorrhizae

Endomycorrhizae vs Ectomycorrhizae

• Endomycorrhizae penetrate plant root cells' cortex while ectomycorrhizae only reach the epidermis without entering cells.

• Endomycorrhizal fungi can survive independently from their host plants; however, ectomycorrhizal fungi rely on symbiotic relationships for survival.

Kingdom Fungi: Understanding Ectomycorrhizae

Overview of Ectomycorrhizae

• The discussion introduces ectomycorrhizae, specifically highlighting fungi that live on the epidermis of plant roots.

• An example provided is the relationship between these fungi and pine trees, which enhances the tree's resilience to drought conditions.

• The explanation emphasizes the symbiotic nature of this relationship, where both organisms benefit from each other.

• The speaker expresses hope that viewers understand the concepts discussed regarding fungi and their ecological roles.

• A note of gratitude is extended to viewers for watching, indicating a conclusion to the topic.