BIO153 - Diversity of Organisms

Morphological Characteristics - Physical characteristics that are shared by species Molecular Characteristicsm - Characteristic determined by specific DNA or protein sequences Phylogeny - A hypothesis for the evolutionary history of a species or group of species Represented as evolutionary trees Systematists - Study morphological and behavioural resemblances as well as molecular similarities and differences to devise theories about relationships Concept 26.1 - Phylogenies Show Evolutionary R

Phylogenies Phylogenetic trees are an extremely effective way of summarizing data on the evolutionary history of a group of organisms Synapomorphy - a trait that certain groups of organisms have that exists in no other They allow biologists to recognize monophyletic groups – also called clades or lineages i.e. Fur and lactation are synapomorphies that identify mammals as a monophyletic group Synapomorphies are characteristics that are shared because they are derived from traits that existed in t

Concept 27.1 - Structural and Functional Adaptation Prokaryotes First organism to inhabit Earth Unicellular Well organized 0.5-5 μm cells Indispensable in nitrogen cycle Widely used for bioremediation 3 Main Groups of Archaea Methanogens Extreme halophiles Extreme thermophiles Cell - Surface Structures Cell wall maintains the shape, protects and prevents it from bursting in hypertonic environment Mycoplasmas - Bacteria that lack cell walls Subject to lysis in hypotonic conditions Peptidoglycan

Four Criteria for a Causative Link To establish a causative link between a specific microbe and a specific disease, Koch proposed that four criteria had to be met: The microbe must be present in individuals suffering from the diseases and absent from the healthy individuals The organism must be isolated and grown in a pure culture away from the host organism If organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear The organism should

Protists Eukaryotes Have a nucleus and other membrane-enclosed organelles Well-developed cytoskeleton Unicellular Polyphyletic structural and function diversity in protists Carry out essential functions with subcellular organelles Nucleus, ER, golgi apparatus, lysosome Wide variety of nutritional lifestyles Photoautotrophs, heterotrophs, mixotrophs (photosynthesis + heterothrophic nutrition) Variation of reproduction and life cycle 4 Supergroups of Eukaryotes Excavata - Morphological studies of

Concept 29.1 - Land Plants Evolved from Green Algae Charophytes - Green algae The closest relatives of land plants Morphological and molecular evidence Morphological, biological traits, and nuclear similarities proves Land plant traits show in protists Multicellularity, similar photosynthetic pigments, cell wall composed of cellulose Acquired independently Rings of cellulose-synthesizing proteins in the plasma membrane Synthesize the cellulose microfibrils of the cell wall Non Charophyte algae

As you study the phylogenetic tree, note that protists do not make up a morphological group Protists constitute as a paraphyletic group meaning that they represent some but not all of the descendants of a single common ancestor No synapomorphies define the protist There is no trait that is found in protists but no other organisms Examples of Protists' Involvement in the World The most spectacular crop failure in history, the Irish potato famine, was caused by a protist: Phytophthora infestans.

Concept 30.1 - Seeds and Pollen Grains are A Key Adaptation for Life on Land Advantages of reduced gametophytes Gametophytes reduction lead to seed plants Gametophytes can develop from spores retained within the sporangia of the parental sporophyte Protection from environmental stresses in the most moist reproductive tissues UV radiation and desiccation Obtain nutrients CON - Free-living gametophyte of seedless plant fend for themselves Ovules and production of eggs Integument - Layer of spo

An Overview of Plants Land plants were the first organisms that could thrive with their tissues completely exposed to the air instead of being partially or completely submerged Plants are said to provide ecosystem services because they add to the quality of the atmosphere, surface water, soil, and other physical components of an ecosystem – plants alter the landscape in ways that benefit other organisms Produce oxygen via oxygenic photosynthesis Build soil by providing food for decomposers Hold

Concept 31.1 - Fungi are Heterotrophs that Feed by Absorption Grow by forming multicellular filaments to obtain food Nutrition and Ecology Absorb nutrients by secreting powerful hydrolytic enzymes Break down complex molecules to similar organic compounds Some use enzymes to penetrate the cell walls Decomposer fungi obtain nutrients from nonliving organic material Essential component of global carbon cycling Parasitic fungi obtain nutrients from the living hosts cells Mutualistic fungi obtain fr

An Overview of Fungi Fungi absorb nutrition from other organisms – dead or alive Fungi that absorb nutrients from dead organisms are the world’s most important decomposers Although a few types of organism can digest the cellulose in plant cell walls, fungi and a handful of bacterial species are the only organisms capable of completely digesting both the lignin and cellulose that make up wood Because they recycle key elements such as carbon, nitrogen, and phosphorus and because they transfer key

Animals are Multicellular, Heterotrophic Eukaryotes with Tissues that Develop from Embryonic Layers Cell structure and specialization Animals are eukaryotes and multicellular Lack structural support of cell walls Animal cells are organized into tissues, nervous tissue is responsible moving the body and nerve impulse Gastrulation - Layers of embryonic tissues that develop into adult body parts (developing stage is gastrula) Larva - Sexually immature form of an animal and morphological distinct

An Overview of Animals Animals are a particular species rich and morphologically diverse lineage of multicellular organisms on the tree of life Animals are distinguished by several traits other than multicellularity, eating, and moving – The cells of animal’s lack cell walls but have an extensive extracellular matrix which includes proteins specialized for cell-cell adhesion and communication Animals are the only lineage on the tree of life with species that have muscle tissue and nervous tissue

Sponges are Basal Animals that Lack True Tissues Sponges are suspension feeders - they capture food particles suspended in the water that passes through their body Sponges represent lineage that originates near the root of the phylogenetic tree of animals Sponge body consists of two layers of cells separated by mesophyll Amoebocytes - Take up food from the surrounding water and from choanocytes (captures food particles), digest it and carry nutrients to other cells Hermaphrodites Each individu

An Overview of Protostome Animals There are 22 phyla of protostome animals but 8 major ones Protostomes are bilaterally symmetric, triploblastic, coelomate animals. Phylogenetic studies have long supported the hypothesis that protostomes are a monophyletic group This result means that protostome developmental sequence arose just once But when recent analyses of DNA sequence data indicated that 2 major subgroups existed within the protostomes, it was considered a key insight into animal evolution

Chordates Have a Notochord and a Dorsal Hollow Nerve Cord Notochord Longitudinal flexible rod located between the digestive tube and the nerve cord Pharyngeal clefts develop into slits that open to the outside of the body. Pharyngeal slits allow water entering the mouth to exit the body without passing through the digestive tract Vertebrates are Chordates that Have a Backbone Hagfishes Jawless vertebrates that have highly reduced vertebrae and a skull that is made of cartilage They have a sm

An Overview of Deuterostome Animals Four phyla of deuterostomes Echinodermata Hemichordate Xenoturbellid Chordates All deuterostomes are considered bilaterians But a remarkable event occurred early in the evolution of echinoderms the origin of a unique type of type of radial symmetry adult echinoderms have bodies with five-sided radial symmetry called pentaradial symmetry (STAR FISH) even though both their larvae and their ancestors are bilaterally symmetric the other remarkable event in echino

This chapter has 2 goals: explore how biologists go about studying ecology analyze the major types of environments that organisms occupy Four Main Levels of Ecology In Ecology, researchers work at four main levels 1) organisms 2) populations 3) communities 4) ecosystems Organismal ecology – morphological, physiological, and behavioural adaptations that allow individuals to live successfully in a area focuses on how organisms respond to stimuli from their environment Population ecology – how t

Learning Establishes Specific Links Between Experience and Behaviour All individuals in a population exhibit virtually the same behaviour, despite internal and environmental differences during development and throughout life Innate Behaviour Developmentally fixed behaviour Behaviour is variable depending on experience How an animal’s experiences during growth and development influence the response to stimuli Cross-Fostering Study Young of one species are placed in the care of adults from ano

An Overview of an Organism's Behaviour it is important to recognize that efforts to explain behaviour at the proximate and ultimate levels are complementary To understand what an organism is doing, biologists want to know how the behaviour happens and why it is common to observe innate behaviour in response to 1) situations that have a high impact on fitness and demand a reflex-life, unlearned, response 2) situations where learning is not possible web-weaving in spiders and nest building in bird

Learning How to Preserve Biodiversity To get a complete understanding of the diversity of life, biologists recognize and analyze biodiversity on 3 levels 1) Genetic diversity is the total genetic information contained within all individual of a species and is measured as the number and relative frequency of all ales present in a species 2) Species diversity based on the variety of species on earth measured by quantifying the number and relative frequency of species in a region taxonomic diversit

Human Activities Threaten Earth’s Biodiversity Biodiversity - Biological diversity Extirpation - Local extinction Global extinction of a species - Lost from all the ecosystems Extinct - Species that are already gone Endangered species - Facing imminent extirpation/extinction Threatened species - Likely to become endangered if nothing is done to reverse the factors causing its decline Example Endangered - Caribbean coral reef ecosystems Critically endangered - Raised bog ecosystems in Germa