Bio Lab Activity 8 Flashcards
Where are the kingdoms Fungi, animalia and Plantas?
Kingdom Fungi and Animalia belong in the Supergroup Unikonta.
Kingdom Plantae in the Supergroup Plantae.
Multicellularity
Multicellularity has evolved in at least 25 separate lineages, and all three eukaryotic kingdoms have multicellular members
•Kingdoms Plantae and Animalia have multicellularity as a phylogenetic characteristic.
•Kingdom Fungi has both unicellular and multicellular members
•Evidence suggests that Fungi and Animalia diverged first (1000- 760 million years ago (m.y.a), while Plantae diverged later with the colonization of land (475 m.y.a.)
•colonization of land by plants was facilitated by symbiotic associations with fungi; evidence for these associations exists in the fossil record and from extant (i.e., living) plants
•advantages of multicellularity include environmental protection, cooperative metabolism, and escape from predation
•improving dispersal abilities and decreasing the need for noncooperative interactions have been suggested as multicellular advantages.
•costs include an increase in resources/energy to support a multicellular individual and increased developmental time to grow resulting in increased generation time of the population
•Both Kingdom Fungi and Animalia have a high number of species found in aquatic environments.
-logical considering that if an organism is small enough, and with enough surface area exposed to the water, then the osmotic and excretory needs can be met across the cell membrane via cell organelles
•As organisms increase in size, they require specialized tissues and/or organs to meet oxygen and nutrient demands, as well as carry waste from cells.
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Understand how different environments may select for different organs and tissues through natural selection.
Consider how the environment puts selection pressure to develop specialized structures as you look at the representative specimens.
Kingdom Fungi
•Fungi and Animalia share a common ancestor in the Supergroup Unikonta, clade Opisthokonta and share a heterotrophic lifestyle.
•heterotrophic nutrition via organic molecules absorbed through the cell surface is a shared derived character.
•common ancestor of all fungi is thought to be a unicellular, flagellated parasite of microalgae that had chitin at some point in the lifecycle.
•half of the identified fungi are saprophytes (saprotrophic), that is they derive their energy from the degradation of dead organic material
•few species are even predaceous, developing mechanisms for capturing small animals to use as a food source —>Nematodes
•other half of fungi have symbiotic roles wherein they form a physically and physiologically close association with another organism (e.g., with algae to form lichens, with higher plants to form mycorrhizae)
•Mycorrhizae are a sheath of fungal cells (hyphae) that live in association with most plant roots and absorb photosynthates from the plant in exchange for water, nitrogen, phosphorous and minerals
•some members are parasitic on living organisms (plants, animals, and even other fungi), destroying crops and causing a wide variety of diseases.
•Fungi are a diverse assemblage of organisms which usually produce a network of branching, more or less cylindrical cells called hyphae (singular, hypha)
•most have the ability to produce spores (both sexually and asexually)
•hyphae form a densely branched network of filaments called a mycelium
•Enzymes and peroxidases are excreted into the environment from the hyphae, and the resulting breakdown of organic matter occurs extracellularly, due to the large size and chemical nature of these compounds.
•smaller molecules that result from this activity are then taken up by the cells for further digestion or immediately used for cell processes- assuming the fungus can uptake the released nutrients before other soil organisms like bacteria steal it.
•Some of these enzymes are another shared derived characteristic of the kingdom.
•Chemicals excreted by fungus to gain nutrition or to decrease competition from other organisms can make the substrate they colonize or the structures they produce like mushrooms, our food, or other organic matter unpalatable or even deadly poisonous
•hyphae of fungi have cell walls strengthened with chitin (a shared derived characteristic of the kingdom) and many have the hyphae divided into “cells” by cross-walls or septa; these are called septate hyphae
•Fungi with hyphae that do not have septa are called coenocytic hyphae – the ancestral condition
•Even if the cells have cross walls, there are pores that promote cytoplasmic streaming between the cells, allowing nutrients to move from one part of the mycelium to other parts
•This is an adaptative advantage to the mycelium, as food resources can be transported from areas that are high in nutrients to places that are low; however, nuclei may also move freely through the mycelium which is problematic for sexual reproduction.
•mycelium germinates from spores, and always starts out haploid (n). In some phyla, the haploid mycelium joins with an opposite mating type create a heterokaryotic mycelium that has nuclei from both partners (n+n). If each cell of the mycelium contains two different but unfused nuclei it is termed a dikaryotic mycelium
•The dikaryotic mycelium will then produce a multicellular reproductive structure. Determination of the phylum a fungus belongs to is traditionally based on the reproductive lifecycle
Key concept:
•The fungal body generally exists as a mass of connected thread-like cells growing through the environment. Each thread is called a hypha, many threads are hyphae. All connected threads make up the body of the fungus, or the mycelium. This body can extend over small or large areas.
Kingdom Animalia:
•all animals share the derived characteristics of being heterotrophic, multicellular organisms whose bodies are composed of eukaryotic cells
•vast majority are also diploid, with the exception of a few male insects who have a derived characteristic of being haploid.
•evolved from a common ancestor with choanoflagellates over 700 million years ago.
•probably the most diverse in cell types and body form of all the kingdoms. The smallest are microscopic (e.g., rotifers) and the largest living members are the whales.
•most animal phyla are found in water or associated with water.
•Marine species are the most abundant, followed by freshwater species.
•terrestrial animal species are found only in two phyla: Arthropoda and Chordata. As well, members of these two phyla are the only ones that have developed flight.
•do not have cell walls but have the shared derived characteristic of the protein collagen that connects cells and is flexible, allowing for movement
•Motility is another shared characteristic of the Animalia – all are motile at some point in their life.
•After the formation of the unicellular zygote, all animals produce a multicellular adult form, a process called ontogeny
•Most animals follow a specific pattern of embryonic development where the zygote divides and develops into a blastula, which is a hollow, spherical mass of cells
•All cells in a blastula are similar, as no cellular differentiation has yet occurred. As the blastula develops into a gastrula, however, distinct germ layers appear - a process called gastrulation
•Germ layers are composed of similar types of cells, and they are identifiable primarily by their position in the embryo.
•In some of the early diverging animal phyla only two germ layers, endoderm and ectoderm, develop in the embryo, whereas in the rest of the phyla a third germ layer, the mesoderm, also appears between the other two layers.
•Embryos that have only two germ layers are referred to as diploblastic, and those with three germ layers are triploblastic.
•As development of the embryo proceeds, each germ layer develops into specific types of tissues that make up the adult body.
Key concept:
•Gastrulation is the pattern of embryonic development that creates germ layers: groups of cells that will form tissues in animals with nerve cells or systems. Two or three germ layers may develop, depending on the animal
group. If two layers develop, the animal will have an endoderm and ectoderm. If three layers develop, the animal will have an endoderm, mesoderm and ectoderm
•Phylum Chordata. Chordates are a diverse group of animals that includes both invertebrates (without backbones) and vertebrates (with backbones)
•first chordates are believed to have been invertebrate filter-feeders; but most living species of chordates have a backbone composed of metameric vertebrae (Subphylum Craniata), and as a group display a wide array of feeding habits.
•Chordates are bilateral animals that typically have a complex closed circulatory system.
•Despite the enormous diversity within this phylum, there are four diagnostic (shared derived) characteristics that distinguish chordates from all other animals
- Notochord - a semi-rigid endoskeletal rod that provides strength and longitudinal support. Located dorsally along the back it allows lateral bending while preventing a shortening, or telescoping, of the body when associated muscles contract. In most vertebrates the embryonic notochord is replaced by a bony vertebral column.
- Dorsal hollow nerve cord - unlike the ventrally located, solid, double strand of nervous tissue typical of annelids and arthropods, the nerve cord of chordates is a hollow, single strand of tissue located just dorsal to the notochord.
- Pharyngeal slits or clefts - slit-like openings in the wall of the pharynx that facilitated filter-feeding in the early chordates. As gills developed in association with the pharyngeal slits in fish-like forms, these structures became respiratory in function. The pharyngeal slits of terrestrial chordates appear only as transitory structures in early stages of embryonic development.
- Muscular post-anal tail - an elongation of the body posterior to the anus, which contains extensions of the notochord and dorsal nerve cord; originally served as a locomotory structure.
Key concept:
•Adaptation to terrestrial ecosystems can be seen in the respiratory and circulatory systems of animals. Fish have a single atrium and ventricle for one way flow of deoxygenated blood to the gills and oxygenated blood to tissues, whereas amphibians have a 3- chambered heart that allows oxygenated and deoxygenated blood to mix. Rats and other mammals, adapted to terrestrial life and air breathing, have a 4-chambered heart which completely separates oxygenated and deoxygenated blood
Kingdom Plantae:
•Current evidence supports the hypothesis that the first plants originated from a Charophycean ancestor (a species of green algae) over 500 million years ago
•In contrast to fungi and animals, plants are multicellular organisms with cellulose cell walls. In moving from an aquatic to terrestrial habitat, this new photoautotrophic lineage of organisms had to overcome many problems related to the lack of water. Specifically, how to acquire and conserve water, transport it to other parts of the plant, and replace the support water provided to the plant body while allowing for gas exchange to all tissues.
•To overcome some of these problems, land plants have evolved apical meristems (localized region of cell division) to acquire water and light
•Selection favored several modifications to the reproductive structures, the embryos, and dispersal structures
•modifications were beneficial in assisting plants to transition from an aquatic to terrestrial environment, early land plants did not have true roots to absorb nutrients. Instead of roots early land plants are thought to have absorbed nutrients and water from the earlier mentioned mycorrhizae
•As evolution of the plant kingdom progressed, new groups that were increasingly better adapted to a terrestrial existence appeared.
•Plants are traditionally divided into “non-vascular” or “vascular” plants based on the type of conducting tissues present
•first plants to invade land were non-vascular and are believed to have had limited absorptive tissues called rhizoids that primarily served to attach to the substrate
•Support was from the cellulose cell walls, which did not provide the mechanical strength to grow up very far
•They had simple leaves one or cell layers thick along the stem, tissues that are the main photosynthetic organ of the plant
•modifications to the reproductive tissues to survive on land were **contingent on the evolution of openings in the epidermis to allow gas exchange for photosynthesis
•first of these openings were always open, allowing gas to diffuse in and out of the tissue, and over time selection favored the development of the openings into stomata to regulate gas exchange for the thicker tissues
•Stomata are tiny openings that open and close by turgor pressure that release water vapor and allow carbon dioxide to enter the plant body
•Stomata can close if the plant is experiencing stress due to a lack of water to make up for the water evaporating during photosynthesis.
•Additionally, a protective waxy layer, the cuticle, is often present on the epidermis to minimize water loss
•Competition for sunlight favored the evolution of support to be taller, and in turn this was dependent of the development of transport systems to move water and food throughout the body: the vascular tissue.
•Vascular tissue in plants consists of two types of tissue: xylem and phloem
•Xylem tissue is responsible for water and dissolved mineral transport (usually in an upward direction) and support is provided in terrestrial plants through lignin (which may be in other cells as well)
•Soon after cell maturation the protoplast of xylem cells dies*, but the walls persist and function in conduction of water even while dead (in trees, this is the wood).
•Phloem** is primarily responsible for the movement of food products within the plant and is alive when functional as a conducting agent (in trees, this is the bark).
Key concept:
•The move to a terrestrial habitat had benefits: ample sunlight, carbon dioxide, and nutrients in the soil. But water is limited, and plants had to develop partnerships (mycorrhizae) or adaptations to minimize water loss.
Common white mushroom
Agaricus sp.
•is actually the fruiting body or basidiocarp of this fungus that is produced by the dikaryotic mycelium
•cap, which is supported by the stalk, protects the gills where the basidiospores develop from the basidia gills radiate out from the stalk like the spokes of a wheel
Members of the Class Actinopterygii
•fishes that have bony skeletons, jaws, scales, a protective operculum covering the gills, and a buoyancy organ, the swim bladder
•fish body consists of three main regions, the head, trunk, and tail
•head region extends from the anterior tip of the snout to the posterior edge of the operculum, the hard bony plate covering the gills.
•trunk is the region from the back of the head to the anus, which is the small opening on the mid-line of the ventral surface approximately two-thirds of the way back on the body. The area of the body posterior to the anus, and which includes the caudal fin (tail fin), is the tail.
•Each gill consists of numerous gill filaments that are attached to the outside of a gill arch. The spaces between gill arches are gill slits.
•The gills are where respiratory gas exchange occurs.
•lateral line, a line of pores extending the length of the entire body approximately halfway up each side. Sensory receptors in the lateral line enable the fish to detect movement by sensing changes in pressure produced by water currents
•trunk and tail are covered with scales. A mucous coating protects the fish from bacterial infection and facilitates movement in water by reducing friction.
•two dorsal fins; a ventral anal fin just posterior to the anus; a caudal fin at the posterior end of the tail; a pair of pectoral fins located laterally on the anterior region of the trunk, one on each side of the body; and a pair of pelvic fins just posterior and ventral to the pectoral fins.
•Each fin is supported by a series of hardened fin rays. In most fishes, fins are used primarily for steering and maintaining stability, with lateral undulations of the body providing the main propulsion for swimming.
•V-shaped arrangement of the muscle segments. These muscle segments are called myomeres, and they are indicative of the metamerism that occurs in the chordates. The propulsion for swimming is provided by lateral undulations of the body produced by the direct action of the myomeres on the vertebral column. Bending of the body occurs when the myomeres on one side contract and those in the corresponding region on the opposite side relax. As sequential waves of contraction and relaxation pass longitudinally along the myomeres the body undulates from side to side providing a powerful swimming force.
•single large ovary that lies in the posterior region of the body cavity. However, if the ovary is filled with eggs, it may occupy most of the cavity. Males have a pair of testes, which occupy the same position in the body cavity as the ovary of females.
•two-chambered heart lies in the pericardial cavity located just ventral and posterior to the gills. It consists of a large thin-walled atrium that lies dorsal to the smaller, muscular ventricle
frog anatomy
•amphibian lungs that are capable of breathing in a terrestrial environment
•3-chambered heart. Two atria and a single ventricle allow blood to become oxygenated based on the current environment of the frog.
•If the frog is present in a terrestrial environment, oxygen comes predominantly from the lungs. In aquatic environments, the vessels leading to the skin expand and those to the lungs close off
•results in some oxygen uptake through the skin so the amphibian can breathe underwater. Depending on the mode of gas exchange, oxygenated and deoxygenated blood will mix at some point in the cycle
Vascular Plant Organs
Some of the other problems faced by plants in terrestrial habitats include:
- Acquiring water and transporting it to other parts of the plant.
- Means to conserve water in the desiccating terrestrial habitat.
- The need for internal support once the supporting nature of an aquatic habitat is gone.
- A mechanism for gas exchange.
•Plants have more limited types of cells and tissues than animals, but more variety than in the fungi.
•Plant growth is via zones called apical or lateral meristems, the apical meristems are at the tip of the stem and root for primary growth while the lateral meristems are for secondary growth
•three organ systems, the root, stem, and leaf. Each organ system has three tissue types: dermal (outer protective covering), vascular (long distance transport), and ground (storage, photosynthesis, and support) tissue
•epidermis and cuticle (dermal tissues)
• xylem and phloem (vascular tissues)
• pith (tissue inside the vascular tissue of root and stem) and cortex (tissue outside the
vascular tissue of root and stem)
• stomata, palisade mesophyll (the tightly packed layer next to the epidermis of the leaf)
and spongy mesophyll (ground tissue in the center of the leaf)
Root
• To be completely terrestrial, plants must be able to acquire water from the ground. Having roots provides not only a structure for anchoring the plant in place, but also provides a site for uptake of water from the soil around the plant
Stem
•division of labour in plants that saw the development of water gathering roots and food producing shoots created the need for support and transport systems in these plants. Thus, the evolution of vascular tissue.
•Vascular tissue in plants consists of two types of tissue: xylem and phloem however, both are composed of a number of cell types. Xylem and phloem are often grouped together to form vascular bundles.
•The xylem is the larger cells surrounded by the smaller phloem
Leaf
•It is in the leaves of terrestrial plants that most of the photosynthesis occurs and, therefore, where most of the gas exchange takes place. You should recall that water and carbon dioxide, along with sunlight, are the primary requirements for photosynthesis.
•Water is absorbed at the roots and transported via the xylem to the leaves where it is needed. Gas exchange occurs through tiny openings on the leaves called stomata (generally found on the underside of the leaves)
•palisade layer is the region of the leaf where the majority of photosynthesis occurs, and underneath you should fine the spongy mesophyll layer consisting of loosely arranged cells with many inter-cellular spaces among them.
•should see vascular bundles with xylem and phloem in the center of the leaf. On the lower surface look for the stomata, surrounded on both sides by small oval cells, guard cells
•upper and lower surfaces of the leaf cross section will
have the waxy cuticle on the surface of the epidermis.
Kingdom Fungi: Main Characteristics
 Heterotrophic → saprophytes
•No chloroplasts
•Hyphae increase absorption
•Mycelium = many hyphae
•Chitin (cell walls)
• High surface area = issues with water loss —> so limited to moist environments
• Spores (in most) allow dispersal
•Generally from multicellular fruiting body
•Hyphae are similar cells that from the body of the fungus; they may form a more complex structures for reproduction
Septa:
•—regular cross-walls formed in hyphae. Hyphae with septa are septate, those lacking septa except to delimit reproductive structures and aging hyphae are called coenocytic.
•primary septa are formed as a process of hyphal extension and generally have a septal pore, which allows for cytoplasmic and organelle movement.
•Secondary or adventitious septa are imperforate, formed to wall off ageing parts of the mycelium.
