1. Characteristics and Classification of Living Organisms - LNg 2022.pdf

Unit 1: Characteristics and Classification of Living Organisms 1.1 Characteristics of living organisms: Describe the characteristics of living organisms by defining the following terms: Movement Respiration Sensitivity Growth Reproduction Excre...

Unit 1: Characteristics and Classification of Living Organisms 1.1 Characteristics of living organisms: Describe the characteristics of living organisms by defining the following terms: Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition 1.2 Concept and uses of classification systems State that organisms can be classified into groups by the features that they share Describe a species as a group of organisms that can reproduce to produce fertile offspring Describe the binomial system of naming species as an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species Construct and use dichotomous keys based on identifiable features 1.2 Concept and uses of classification systems Explain that classification systems aim to reflect evolutionary relationships Explain that the sequences of bases in DNA are used as a means of classification Explain that groups of organisms which share a more recent ancestor (are more closely related) have base sequences in DNA that are more similar than those that share only a distant ancestor 1.3 Features of organisms State the main features used to place animals and plants into the appropriate kingdoms State the main features used to place organisms into groups within the animal kingdom, limited to: the main groups of vertebrates: mammals, birds, reptiles, amphibians, fish the main groups of arthropods: myriapods, insects, arachnids, crustaceans State the main features used to place organisms into groups within the plant kingdom, limited to ferns and flowering plants (dicotyledons and monocotyledons) State the main features used to place all organisms into one of the five kingdoms: Fungus, Prokaryote, Protoctist State the features of viruses, limited to protein coat and genetic material 1.1 Characteristics of living organisms What is Biology? Biology is the study of living organisms How do we decide if something is living or non-living?  Let’s say you’re an alien and this is your first time on earth. You made some observations about the objects you see.  The tree changes with A tree doesn’t the seasons A tree can seem to move make its own food The leaves can take in The roots can oxygen take in water So, what makes a tree a living thing and a car a non-living thing? Life Processes If something is alive, it will carry out all seven life processes. Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition Characteristics of Living Things Movement: action by an organism or part of an organism causing a change of position or place Animals move to find food, shelter or a mate. Plants do not move in the same way as animals but move towards sunlight. Characteristics of Living Things Respiration: chemical reactions in cells that break down nutrient molecules and release energy for metabolism Also known as release of energy from food, requires oxygen Which animal cell organelle is involved in this process?  Characteristics of Living Things Sensitivity: ability to detect and respond to changes in the internal or external environment Animals find their way using their sense organs such as the eyes or skin. Plants don’t have sense organs but do respond to gravity and light. https://www.youtube.com/watch?v =PJe2k_PFSBE Characteristics of Living Things Growth: permanent increase in size and dry mass Animals stop growing when they reach adult size. Plants grow throughout their lives. Characteristics of Living Things Reproduction: processes that make more of the same kind of organism Animals lay eggs or have babies. Seeds from plants grow into new plants. Characteristics of Living Things Excretion: removal from organisms of the waste products of metabolism, toxic materials, and substances in excess of requirements Animals excrete through their lungs, kidneys and skin. Plants shed their leaves in autumn Characteristics of Living Things Nutrition: taking in of materials for energy, growth and development All living things need food for energy, growth and repair. Animals have to find their own food by eating plants and other animals. Plants make their own food by the process of photosynthesis. 1.2 Classification of living organisms Why is there a need for classification? Classification makes the identification of living organisms easier Organisms are sorted into groups according to features they have in common. Main classification group – species Species A species is a group of organisms that can breed together to produce fertile offspring. Fertile means that they can reproduce when they become an adult Linnean Classification System Carl Linneaus Swedish botanist, zoologist, taxonomist and physician Father of modern taxonomy Created the system to name organisms Linnean Classification System Largest Kingdom King Phylum Philip Class Came Order Over Family For Genus Good smallest Species Soup Example: Wolf Largest Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Canidae Genus Canis smallest Species Lupus Binomial Naming System Scientific name of any organism contains 2 parts: Genus and species Genus always has a capital letter Species always no capital letter Must be italicised when typed Must be underlined when handwritten Examples Canis lupus – the wolf Panthera leo – the lion  Kingdoms Animals Fungi Protists Plants Bacteria Monocots Dicots Vertebrates Invertebrates Nematodes Annelids Molluscs Arthropods Insects Crustaceans Arachnids Myriapods Mammals Reptiles Birds Fish Amphibians Five Kingdoms Bacteria Very small and single-celled, no nucleus Protists Single celled, with a nucleus Fungi Cell walls contain chitin, with a nucleus Plants Multicellular organisms Can make food through photosynthesis Animals Multicellular Have to obtain food Kingdom Monera (Bacteria) — Single-celled prokaryotes (do not have a nucleus) — Microscopic — Possess a cell wall — Possess a plasma membrane and cytoplasm, containing glycogen granules — Some have a slime capsule — Some have 1 or more flagella Parts of a Bacterium flagellum cytoplasm cell wall strand of cell surface capsule DNA membrane Scanning electron micrograph of bacteria on the point of a pin. Prokaryotes (bacteria) and eukaryotic cell (cheek cells) Flagella Flagellum — This E. coli bacterium displays well- preserved flagella that are just 30 nanometers long. — Ang Li/National University of Singapore Bacterial flagellum motor Specialized membranes of prokaryotes Bacteria Colony Cultures E. coli dividing by binary fission Classification of bacteria according to shape Coccus Bacillus (sphere) (rod) Spirilla (spiral) Kingdom Monera (Bacteria) Streptococcus Escherichia coli (higher magnification) Kingdom Monera (Bacteria) Nostoc sp. Spirulina sp. Kingdom Protista (Protoctist) Unicellular eukaryotes with a distinct membrane-bound nucleus Usually motile (can move)à Made possible by pseudopodia, and beating of flagella or cilia Some can make their own food (protophyta), e.g. euglena Some take in and digest food (protozoa), e.g. amoeba and paramecium Kingdom Protista Amoeba Kingdom Protista Paramecium Kingdom Protista Euglena sp Kingdom Protista Chamydomonas sp Amoeba proteus, a unicellular "protozoan" Use of pseudopodia for feeding Kingdom Fungi They are multicellular organisms composed of thread-like hyphae which form a network called a mycelium. Their cell walls are made up of chitin. Hyphae may be divided by cross-walls (septa) into short segments or may merge together with nuclei spread along the cytoplasm. Do not produce chlorophyll and thus do not photosynthesize Kingdom Fungi They secrete enzymes to digest food outside the cells and absorb the soluble products Fungi are parasitic or saprophytic in their nutrition. Some produce spores in a sporangium or cap. Parasitic fungi cause disease eg. ringworm Some are used in food production Some strains of yeast used in making bread, beer and wine Some types of mushrooms are edible Fungi Kingdom Fungi (under microscope) High power images of a fungus showing thread-like hyphae septa Athlete’s foot/ Tinea Ringworm The Plant Kingdom Multicellular Eukaryotic cells which contain a distinct membrane-bound nucleus Possess a cellulose cell wall Usually contain chloroplasts filled with chlorophyll and are thus able to photosynthesize Chlorophyll in chloroplasts Coniferophyta (non- flowering plants fir pine Angiospermophyta (flowering plants) Possess roots, stems and leaves Possess xylem and phloem for transport Produce flowers as part of their reproductive cycle Produce seeds enclosed in a fruit formed from ovary 2 Classes of Flowering plants Monocotelydons Dicotelydons Class Monocotyledoneae (monocots) Have long and narrow leaves Leaves have parallel veins Seeds contain single cotyledon or seed- leaf Flower parts are grouped in threes Monocots rice corn Vanda Miss Joaqium Class Dicotyledoneae Leaves are usually broad With network of veins Seeds contain 2 cotyledons Flower parts are grouped in fours or fives Class Dicotyledoneae Hibiscus Kidney Bean Plant Monocots vs Dicots Source: ib.bioninja.com.au Monocotyledons and Dicotyledons FEATURE MONOCOTYLEDON DICOTYLEDON Leaf Shape Long and narrow Broad Leaf veins parallel Branching Cotyledons one Two (seed leaf) Grouping of In threes In fives flower parts Kingdom Animalia Multicellular Cells do not have cell wall. Do not possess chlorophyll and thus do not photosynthesize. They are heterotrophic obtaining nutrients by eating & digesting other living organisms Usually mobile 5 Phylums of Animals Annelida (invertebrate) Nematoda (invertebrate) Mollusca (invertebrate) Arthropoda (invertebrate) Chordata (vertebrate) Phylum Annelida (segmented worms) Bodies are usually elongated and cylindrical Bodies are divided into many equal segments Mouth and anus present Each segment carries a number of chaetae (bristles) which aid in locomotion May have a clitellum Figure 33.23x External anatomy of an earthworm Clitellum Figure 33.24 Annelids, the segmented worms: Polychaete (left), feather-duster worm (middle), leech (right) Phylum Nematoda (roundworms) Long and cylindrical body Body not segmented Body pointed at both ends May be parasitic Phylum Mollusca Most have a shell, hardened by calcium carbonate Have a muscular foot May have eyes on tentacles Bodies soft and unsegmented Figure 33.18x Garden snail Figure 33.22 Cephalopods: Squid (top left and bottom left), nautilus (top right), octopus (bottom right) Figure 33.19 Gastropods: Nudibranchs (top left and bottom left), terrestrial snail (bottom left), deer cowrie (bottom right) Figure 33.20 A bivalve: Scallop Phylum Arthropoda Special features They are invertebrates They have a waterproof exoskeleton Their bodies are segmented They have jointed limbs Four main classes of arthropod Insects Arachnids Crustaceans Myriapods Insects Key features Three pairs of legs Two pairs of wings One pair antennae Compound eyes Body – head, thorax and abdomen Arachnids Key features Four pairs of legs Body divided into head and abdomen Several pairs simple eyes Chelicerae for biting / poisoning prey Crustaceans Key features Five or more pairs of legs Two pairs of antennae Head and abdomen Exoskeleton forms a hard carapace Compound eyes Myriapods Key Features Ten or more pairs of legs One pair of antennae Simple eyes Phylum Chordata These are the vertebrates, animals which have a supporting rod running the length of the body, called the vertebral column. There are many classes of vertebrates. 5 Classes of Vertebrates (under Phylum Chordata) Mammals Reptiles Birds Fish Amphibians Class Pisces (Fish) Key features Body shape – smooth streamline surface for minimal resistance in water Body coverage – covered with overlapping scales Structures for locomotion – fins Breathing organ – filamentous gills Unable to regulate their own body temperature (poikilothermic) Figure 34.11 Cartilaginous fishes (class Chondrichthyes): Great white shark (top left), silky shark (top right), southern stingray (bottom left), blue spotted stingray (bottom right) Figure 34.12a Ray-finned fishes (class Actinopterygii): yellow perch Figure 34.12b Ray-finned fishes (class Actinopterygii): long-snouted sea horse Class Amphibia (Amphibians) Key features Skin – moist, scaleless Life-cycle – external fertilization, lay eggs in water, tadpole lives in water, the adult form lives on land. Breathing methods – tadpoles breathe through gills, adults breathe through lungs and skin No. of limbs – 4 limbs in the adult often with webbed feet Body unable to regulate temperature Figure 34.17x1 Frogs Figure 34.18 “Dual life” of a frog (Rana temporaria) Class Reptilia (Reptiles) Key features Skin – dry, scaly skin Eggs – waterproof shell (so reptiles lay their eggs on land, internal fertilization Limbs & toes – 4 limbs, 5 toes (vestigial in snakes) Breathe using lungs Body unable to regulate temperature Reptiles lay rubbery egg shells Figure 34.24 Extant reptiles: Desert tortoise (top left), lizard (top right), king snake (bottom left), alligators (bottom right) Class Aves (Birds) Key features Body coverage – feathers Forelimbs – modified into wings Hindlimbs & toes – 4 toes with claws Mouth structure – beak Able to regulate body temperature (homeothermic) Breathe through lungs Internal fertilization, lays eggs with hard shell Figure 34.26 A bald eagle in flight Figure 34.29 A small sample of birds: Blue-footed boobies (top left), male peacock (top right), penguins (bottom left), perching bird (bottom right) Class Mammalia (Mammals) Key features Body coverage – hair or fur Breathing organ – lungs Feeding their young – mammary glands, suckle their young Dentition – different types of teeth Able to regulate body temperature Internal fertilization, most give birth to young alive Figure 34.31 Australian monotremes and marsupials: echidna (top left), marsupial mouse (lower left), sugar glider (right) Figure 34.37 Apes: Gibbon (top left), orangutan (top right), gorilla (bottom left), chimpanzee (bottom right) Orca  Viruses: living or non-living? Viruses, e.g. HIV, influenza, coronavirus Very small NOT cells Contain a strand of DNA or RNA Surrounded by a protein coat (capsid) Only life process they show is reproduction Depend on host cell for everything Using simple keys for classification Dichotomous key “di”: 2; “chotomous” – divide A dichotomous key has two branches at each stage.  Divide the dogs into two groups Group A Group B We divide the dogs into groups by asking a question to which there is a yes or no answer... Is the dog large (above 65cm)?  Large Dogs Small Dogs We can now divide each group down into further sub divisions What question could be used to divide the large dogs down into further groups? Does the dog have a brown and black coat? No Yes white and grey coats brown and black coats Finally the groups can be divided down into individual dogs to which we can then give the names. What question has been used to separate these two dogs? Does the dog have curly hair? yes no Airedale Terrier Rotweiller By asking questions that divide the dogs we can produce a key. To save space biologists list the questions and give instructions at the end as to which question to go to next. 1. Is the dog over 65cm tall? If yes go to question 2 If no go to question 5 2. Does the dog have a brown and black coat? If yes go to question 3 If no go to question 4 3. Does the dog have a wooly coat? Yes… Airedale Terrier No…Rotweiller  Your turn to try! 1. Is the dog over 65cm tall? Complete If yes go to question 2 questions 4 for the If no go to question 5 large dogs and question 5 onwards 2. Does the dog have a for small dogs brown and black coat? If yes go to question 3 If no go to question 4 3. Does the dog have a wooly coat? Yes… Airedale Terrier No…Rotweiller  Example Answer Question 4 Does the tail curl upwards? Yes No Akita Old English sheepdog  For the small dogs Now complete the key, starting with question 5, for the small dogs. You can make your own questions up.  Example Answer Question 5 Does the dog have a snub nose? Yes No Go to question 6 Go to question 7 Question 6 Does the dog have long hair? Yes No Pekinese Bulldog Question 7 Does the dog have very long ears? Yes No Basset hound Dachsund  Statements do not have to be questions 1.Body is cylindrical & elongated go to 2 Body is bilaterally symmetrical go to 3 2.Body is segmented earthworm Body is not segmented round worm 3.Organism has a muscular foot snail Organism has tentacles squid Tips for figuring out the criteria in dichotomous key Statement must be comparing similar types of things Example: legs, segments, antennae, outer covering Statement must be contrasting: 3 pairs vs 4 pairs of legs, 2 vs 3 segments, antennae vs no antennae, fur vs feathers Must only split into 2 groups at a time, not more than that