Unit 1 - Biodiversity - Notes PDF

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Unit 1:- Biodiversity Unit 1: Diversity of Living Things Biodiversity: A term that describes the number and variety of species and ecosystems on Earth. Species: All organisms capable of breeding freely with each other or under natural conditions. ● Hybridization is known as the cross-breeding of two different species. Although hybridization in nature does occur, it is relatively uncommon.

There are currently three types of species concept. They are:Morphological Species:- Characterizes a species by body shape, size, behaviour and structural features Biological Species:- Defines a species as a population of organisms that interbreed to produce viable, fertile offspring. Phylogenetic Species:- The concept of a species as an irreducible group whose members are descended from common ancestors. They all possess a combination of certain defining or traits. Basically it is based on the evolutionary history of an organism. The physical changes that occur in entire population of a species over time are referred to as evolutionary changes. Evolutionary changes usually occur over long periods of time and over long distances.

The limits of the three types: Morphological Species:- some species may look similar but are totally different and some species may look totally different but are the same type. Biological Species: Species of asexually reproducing species and fossils can not be determined. Some hybrids have reduced fertility. Not all mating conditions can be naturally tested. Phylogenetic species: Sometimes there can be no evolutionary history on the species.

Biodiversity has three forms:-

Species Diversity:- A measure of diversity that takes into account the quantity (number) of each species present, as well as the variety of different species present. Species are the basic units of biological classification and thus the normal measure of biological diversity. Species richness is a term that describes the number of different species in a given area. Genetic Diversity:- The genetic variability among organisms; usually referring to individuals of the same species. Structural/Ecosystem Diversity:- The range of physical shapes and sizes within a habitat or ecosystem.

Diversity of Ecosystems:Autotrophs:- an organism capable of synthesizing its own food from inorganic substances or sources of energy using light or chemical energy. Example;- Plants, algae and certain types of bacteria. Heterotrophs:- An organism that cannot synthesize its own food and is dependant upon complex inorganic substances for nutrition. Basically it obtains energy-rich nutrients by consuming living or dead matter.

Diversity of Interactions:Interspecific Interaction:- Interaction between different species in a community. “Inter” means between. Intraspecific Interaction:- An interaction in population ecology, whereby members of the same species compete for limited resources or interact with each other. “Intra” means same. Symbiosis:- A general term used to describe a relationship where two species live together in a long term, intimate association. ● Mutualism:- A relationship between two species who live in a very close association with each other, where both benefit from the association. ● Predation:- A form of symbiotic relationship between two organisms of unlike species in which one of them acts as predator that captures and feeds on another organism that serves as the prey. ● Herbivory:- a type of predation in which animals/organisms consume autotrophs such as plants. ● Commensalism:- A relationship between individuals of two species in which one species obtains food or other benefits from the other without either harming or

benefiting the latter. ● Parasitism:- A relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life. ● Competition:- A symbiotic relationship between or among living things that compete for limited resources such as food, space, shelter, mate, ecological status, etc.

The Nature of Classification Biological classification:- The systematic grouping of organisms into biological categories based on physical and evolutionary relationships. It’s importance is to identify organisms and determine relationships. Taxonomy:- The science of classifying all living and extinct organisms. The purpose of classification is to identify and make natural groups. Organisms are assigned to given ranks called taxa. Domain:- The highest taxonomic level; there are three domains in life: Eubacteria, Archaea and Eukaryotes. Phylogeny:- The study of the evolutionary relatedness between and among species. Phylogenetic Trees:- A diagram depicting the evolutionary relationships between different species or groups. Clades:- A taxonomic group that includes a single common ancestor and all its descendants. Evolution:- The scientific Theory that describes change in species over time and their shared memory.

People Who Came Up Classification Criteria:The Ancients:- Many early classifications were based on the philosophical assumption that each type of organism held a fixed position, rank on a scale from lowest to highest. Humans were placed above animals, and animals were placed above plants. This hierarchy is known as “The Great Chain of Being” or the “Scala naturae”. The philosophy also stated that the species were fixed, unchanging over time. Aristotle:- Categorized according to habitats. Example:- Water dweller, Land dwellers,

Air dwellers. The problem with this classification was that some animals had more than one habitat. For example frogs live in water and land. Carl Linnaeus:- Considered to be “the father of taxonomy”. He introduced a consistent way of grouping organisms according to their morphological similarities. He established a naming system that is still used today. Linnaeus considered species to be distinct types of living things that could be grouped into categories called genera according to their shared characteristics. He then grouped species into taxonomic ranks.

The Taxonomic Classification System:- (King Phillip Came Over For Good Soup) Kingdom, Phylum, Class, Order, Family Genus:- The division of genus is more specific as the grouping before species and after family. Sometimes it is impossible to identify all organisms up to the level of the of the species. In such cases, the genus of an organism is enough to label it. The genus or the generic name precedes the specific name in biological classification. Species:- The lowest division is species which consists of organisms that can interbreed to produce a fertile offspring. Organism have similar set of DNA and similar physical and morphological attributes are said to be of the same species.

Biological Nomenclature:Also known as the binomial nomenclature, it is the system of scientifically naming organisms developed by Carl Linnaeus. It was established as a way to bring clarity to the discussions of organisms, evolution and ecology in general. ● Each scientific name in the biological nomenclature consists of two names, also called the descriptors or epithets. ○ The first word is the generic epithet and describes the genus that the animals belong to. ○ The second word is the specific epithet and refers to the species of the organism. ● When written, the text of a scientific name is usually italicized or underlined, to clarity that it is a scientific name written in binomial nomenclature. ○ The first letter of the genus is always capitalized ○ The species is always written in lowercase.

The International Barcode of Life Project:-

Proposed by Paul Herbert (Researcher at the Guelph University), the idea is to use DNA technology to create a DNA profile of every species in the form of a barcode. Ultimately, researchers would be able to use a handheld device to identity any species from a tiny sample of DNA. This is beneficial because DNA is found in every organism in any stage of their life and it can be even used to identify tissue samples such as hair, feathers, or meat. It’s also a useful tool to control trafficking in products made from endangered species. The iBOL project was launched in 2010. It is supported by 25 countries and involves hundreds of leading researchers.

Dichotomous key:- (Important) A dichotomous key is a series of branching, twopart statements used to identify organisms (or objects) ● Keys consists of a series of choices that lead the user to the correct name of a given item. ● “Dichotomous” means divided into two parts. Therefore, dichotomous key always gives two choices in each step. Example:https://docs.google.com/document/d/1hp08DQvRxcIDZF1NnIDz5mdaPpGVMisS1aO5J7qyrk/edit?usp=sharing Benthic Macroinvertebrates:- Organisms without a backbone that lives at the lowest region of their habitat. In other words, they live in debris, sediments, logs and lake bottom. They are large enough to be seen with the naked eye. They are important because they provide as a food source to fishes and other predators. They have a varied tolerance for pollution and can tolerate many different stream conditions. Biologists monitor their amount in the water to look for changes in the quality of the stream. They spend most of their life in water (limited mobility). They are also easy to collect,analyze and monitor Organic matter contains large amounts of carbon-based compounds. It includes dead matter, living microbe and living parts of plants. Inorganic Compounds do not contain carbon and are not derived from living matter.

They include substances made from single elements, salts, metals and any other compound that do not contain carbon-bonded to hydrogen.

Modes of Nutrition:Autotrophic Nutrition:- A process where the organism prepares their food from the simple inorganic materials like water, mineral, salts and carbon dioxide in the presence of sunlight. ● They contain a green coloured pigment called chlorophyll which helps in trapping energy from the sun. They make their own food through the process of photosynthesis. ● Some autotrophs produce food through the process of chemosynthesis, rather than through photosynthesis. During this process, they make food using energy from chemical reactions, often combining hydrogen sulphide or methane with oxygen. ○ Organisms that undergo chemosynthesis live in extreme environments, where the toxic chemicals needed for oxidation are found. Heterotrophic Absorption:- Nutrition obtained by digesting other organic compounds prepared by other plants or animal tissues. They break down the complex and compounds into similar forms. Heterotrophic mode of nutrition can be further subdivided into three groups called:● Holozoic Nutrition:- Involves consumption of food through mouth (opening); also known as ingestion. It involves all the processes including ingestion,digestion and egestion. ● Saprophytic Nutrition:- This kind of nutrition involves the processing or decomposing the rotten fudge and dead or decaying organic matter of organisms. In this mode of nutrition, secretion of certain enzymes are released which break down the complex food into simpler forms. ● Parasitic Nutrition:- A mode of nutrition where one organism (parasite) lives on the body surface or inside the body of another type of organism. They do not possess the properly developed organs and depend on their hosts for deriving the nourishment.

Kingdom Archaea and Bacteria Archaebacteria are the oldest organisms living on Earth. These bacteria are adapted to living in extreme environmental conditions. They respire anaerobically, so they don't need oxygen and light to survive.

Sub Groups of Archaea:● Methanogens:- Able to reduce CO2 into methane. They are anaerobic and can die if exposed to oxygen. Basically, they obtain energy by converting inorganic molecules. ● Halophiles:- Bacteria that can survive high salty environments. They obtain energy from organic food molecules and light. Habitual Example:- Dead Sea. ● Thermoacidophiles:- They thrive in extremely acidic, hot and moist regions, such as those in and near sulphur hot springs. Examples of habitats:- volcanoes, hot spring, etc. Bacteria:Single celled microbes. The cell structure is simple as there is no nucleus or membrane bound organelles. Their genetic information is contained in a single loop of DNA.

Characteristics of Bacteria:● Bacteria’s chromosome is a single loop of DNA that is found in the region called the nucleoid. ● Ribosomes which are used in protein synthesis are scattered throughout the cytoplasm. ● Bacteria often have one or more flagella for movement and small hair-like structures called pili. The pili are made of stiff proteins and help the cell attach to other cells or surfaces. ● Many bacteria have one or more plasmid in their cytoplasm. A plasmid is a small loop of DNA inside the bacterial cell which usually carries a small number of genes; not essential for cellular functions but provide some advantage to the cell. Genes that give bacteria resistance to antibiotics are often found on plasmids. ● Bacteria have complex cell walls composed primarily of peptidoglycan, a large molecule that forms long chains. ● Some bacteria are also surrounded by a sticky capsule which reduces water loss, resists high temperature and helps keep out antibiotics and viruses. Bacteria can be classified into 3 groups:-

● Cocci (singular - coccus):- These types of bacteria are unicellular, spherical or elliptical shape. They can resist drying. ● Bacilli (singular - bacillus):- These types of bacteria are unicellular, rod-shaped and absorbs more nutrients due to greater surface area. ● Spirilla (singular - spirillum):- These types of bacteria are spiral shaped and they move through fluids with the least resistance. Antibiotic Resistance:Antibiotics are medicines used to prevent and treat bacterial infection. However, antibiotic resistance occurs when bacteria change in response to the use of these medicines. Overuse of antibiotics can cause bacteria to adapt and become resistant. Bacterial Reproduction:- (Asexual) Bacteria reproduce by binary fission. In this process, the bacterium which is single cell divides into two identical daughter cells. Binary fission begins when the DNA of the bacterium divides into two replicates. The bacterial cell then elongates and splits into two daughter cells each with the identical DNA to the parent cell. Each daughter cell is a clone of the parent cell. Sexual Reproduction of Bacteria:- (Conjugation) Conjugation is a process in which two bacteria lie side by side and a portion of genetic material is slowly passed from one bacterium to another. The steps involved are: ● Cells linked by a bridged structure called pili. ● Genetic information passes through one pili to another. ● Receiving cells undergoes Binary Fission. Reproduction of Bacteria Through Spore Formation:Spore is a reproductive cell capable of developing into a new individual without fusion with another reproductive cell. They are agents of asexual reproduction. ● During unfavourable conditions a bacteria enters a dormant phase to protect itself ● It forms a tough outer covering to enclose its DNA ● The resulting product looks like a seed and is called an endospore ● When favourable conditions return, endospore loses its outer coat, allowing the bacteria to grow again.

Asexual

Advantages

Disadvantages

Conserves Energy

Higher risk for Extinction

One Parent

Rapid Reproduction leads to competition

Very Fast Reproduction rate Not easily affected by environmental condition Sexual

Spore

Identical to parent: no diversity

Genes can be manipulated

Uses more energy

Different from parents

Requires two parents

Genetic variation increases the likelihood of the species surviving in changing conditions.

Slow and affected by environmental conditions

Able to resist unfavourable condition (e.g extreme heat, cold, damaging chemicals, drying)

Slow Process No growth during dormancy

Long life span

Protists:Protist, any member of a group of diverse eukaryotic, predominantly unicellular microscopic organisms. They may share certain morphological and physiological characteristics with animals or plants or both. The term protist typically is used in reference to a eukaryote that is not a true animal, plant, or fungus or in reference to a eukaryote that lacks a multicellular stage. Characteristics of Protists:● Some are single celled, some are syncytial (coenocytic; essentially a mass of cytoplasm) and others are multicellular. ● Protists are eukaryotic. They have a nucleus which houses their genetic material.

● Protists mainly undergo asexual reproduction; example binary fission and spore formation. ● They are able to live in many different habitats. Basically they are adaptable to most surroundings.

Three Groups of Protists:Plant Like Protists:- Known as algae but they are a large and diverse group. Plant-like protists are autotrophs. They perform photosynthesis to produce sugar by using carbon dioxide and water, and the energy from sunlight, just like plants. ● Unlike plants, however, plant-like protists do not have true stems, roots, or leaves. Most plant-like protists live in oceans, ponds, or lakes. Protists can be unicellular (single-celled) or multicellular (many-celled). ● Some have flagella and are able to swim. Some have cellulose cell wall. Animal-like Protists:- They are also called Protozoa. Protozoa are singled celled eukaryotes that share similar traits as animals. They are heterotrophs. Some protists have cilia which help them move, others are parasitic and some have long tails (flagella) while others produce spores and do not move at all. ● Cilia - tiny hair like structures that cover the outside of the microbe. They beat in a regular continuous pattern like flexible oars. ● Flagella - long thread-like structures that extend from the cell surface. The flagella move in a whip-like motion that produces waves that propel the microbe around. ● Amoeboid movement - the organism moves by sending out pseudopodia, temporary protrusions that fill with cytoplasm that flows from the body of the cell. Fungi-like Protists:- Also known as molds, they are absorptive feeders on decaying organic matter. They resemble fungi, and they reproduce with spores as fungi do. However, in other ways, they are quite different from fungi and more like other protists. ● Slime molds are fungus-like protists commonly found on rotting logs and compost. They move very slowly in search of decaying matter to eat. ● Water molds are commonly found in moist soil and surface water. Many are plant pathogens that destroy crops.

Fungi:- (Singular fungus) A fungus is a eukaryote that digests food externally and absorbs nutrients directly through its cell walls. Most fungi reproduce by spores and have a body (thallus) composed of microscopic tubular cells called hyphae. Fungi are heterotrophs and, like animals, obtain their carbon and energy from other organisms. Characteristics of Fungi:● Most fungi are multicellular but some exists as single cells (yeasts). ● Cordyceps have familiar reproductive structures but amazing life cycles. They are parasitic fungi of the phylum Ascomycota. They infect an insect host and change its behaviour, forcing it to climb to a high stem. The fungus then kills the host. Its reproductive structure grow through its body and release spores. ● The bodies of most fungi are mesh-like, composed of a branching network of filaments called mycelium. These filaments are called Hyphae. Hyphae are often microscopically thin and they have a structure unlike plants or animal cells.

They consist of long tubes of cytoplasm containing many nuclei. ● The cytoplasm is contained by a cell wall made of chitin. Chitin is a complex chemical found in cell walls of fungi and external coverings of insects and crustaceans such as lobsters and crabs. ● The tubes may be sepa...