Year 13 Biology - Summary and Quiz

Variation refers to any difference between cells, individual organisms or groups of organisms of a species.

<p>Point mutation = Change in the nucleotide sequence involving only one gene Block mutation = Change involves a whole section of a chromosome Duplication = A duplication consists of a piece of DNA that is abnormally copied one or more times Deletion = A deletion changes the number of DNA bases by removing a piece of DNA Insertion = An insertion changes the number of DNA bases by the addition of one gene or by adding a section of DNA</p> Signup and view all the answers

<p>Mutations create and also maintain variations within a population.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>The two types of genetic drift are the founder effect and the population bottleneck.</p> Signup and view all the answers

<p>Gene flow refers to the addition of new alleles into the existing gene pool and changes the allele frequencies. The degree of changes in allele frequencies depends on the differences between the genotypes of the immigrants and the native population.</p> Signup and view all the answers

<p>Genetic engineering refers to the direct manipulation of DNA or genome to alter an organism’s characteristics.</p> Signup and view all the answers

<p>Recombinant DNA is the DNA of an organisme which is altered by the incorporation of a gene, it is also known as recombinant DNA technology.</p> Signup and view all the answers

<p>Restriction endonucleases are enzymes that cut DNA molecules at specific sites.</p> Signup and view all the answers

<p>An exonuclease is an enzyme that removes nucleotides from the ends of a nucleic acid molecule.</p> Signup and view all the answers

<p>The Hardy-Weinberg principle is a mathematical equation that describes the distribution and expression of alleles (forms of a gene) in a population.</p> Signup and view all the answers

<p>Populations must not overlap (A), The population is small (B)</p> Signup and view all the answers

<p>Natural selection is the favoring by the environment of those organisms that are better adapted to it and better able to survive and produce more offspring. Artificial selection is a process where humans select for desirable traits in organisms.</p> Signup and view all the answers

<p>Speciation is the formation of new and distinct species in the course of evolution. It involves the splitting of a single evolutionary lineage into two or genetically independent lineages.</p> Signup and view all the answers

<p>Prezygotic isolation occurs before fertilization can occur while postzygotic isolation occurs after fertilization.</p> Signup and view all the answers

<p>Hybrid inviability (A)</p> Signup and view all the answers

<p>Adaptive radiation is the evolution of species from its common ancestor to a number of different forms adapted to various ecological niches.</p> Signup and view all the answers

<p>The four main types of evidence that support the idea that humans and chimpanzees share a common ancestor are anatomical evidence, molecular evidence, fossil evidence and cultural evidence.</p> Signup and view all the answers

<p>A tool culture refers to the way in which a species uses tools to meet its needs.</p> Signup and view all the answers

<p>A biome is a community on a global scale where habitats bound each other, it is defined by the temperature, precipitation and types of plants and animals that inhabit it.</p> Signup and view all the answers

<p>Savanna (E)</p> Signup and view all the answers

<p>Eutrophication is a process that occurs when lakes, streams and estuaries are over fertilised, excessive production of aquatic organic matter can become a water quality problem.</p> Signup and view all the answers

<p>Biomagnification is the accumulation and increase of substance occurrence in food chains.</p> Signup and view all the answers

<p>A carbon footprint is the total amount of greenhouse gas emissions caused directly and indirectly by activities of an individual, event, organisation, product, usually expressed in equivalent tons of carbon dioxide.</p> Signup and view all the answers

<p>A carbon sink is a reservoir of carbon that accumulates and stores carbon for an indefinite period.</p> Signup and view all the answers

<p>Adaptation is the action taken to reduce the impacts and risks or exploit beneficial opportunities related to climate change. Mitigation is the action taken to reduce emissions and enhance carbon sinks, in order to reduce the rate of climate change.</p> Signup and view all the answers

<p>Viruses are considered to be a sub-cellular form of life, they have no membranes, cytoplasm, ribosomes or other cellular components, they also cannot move or grow and they can only reproduce inside a host cell. Viruses have two major parts: a protein coat and DNA or RNA. They are extremely tiny and can only be seen with an electron microscope.</p> Signup and view all the answers

<p>During the lytic cycle the virus reproduces and lyses or breaks open the host cell, releasing new viruses. During the lysogenic cycle the virus replicates the phage genome without destroying the host.</p> Signup and view all the answers

<p>They are unicellular (A)</p> Signup and view all the answers

<p>Archaebacteria are microbes that live in extreme and harsh conditions, they lack cell wall, their cell membrane is made up of different lipids, and their ribosomes are similar to that of eukaryotes. Eubacteria are known as true bacteria, their characteristic feature is the presence of rigid cell walls and if present a motile flagelllum that aids in locomotion.</p> Signup and view all the answers

<p>Autotrophic bacteria are producers, they are able to synthesize complex organic compounds by photosynthesis, while heterotrophic bacteria are consumers, they depend on other organisms for their food.</p> Signup and view all the answers

<p>A flagellum, if present, will aid in locomotion.</p> Signup and view all the answers

<p>Gram-positive bacteria have a thicker peptidoglycan layer in their cell wall, while Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane composed of lipids.</p> Signup and view all the answers

<p>Bacteria reproduce asexually by binary fission and also sexually by conjugation, transformation and transduction.</p> Signup and view all the answers

<p>Bacteria play important roles in the environment, they are the natural scavengers on the earth and are capable of degrading biochemicals in soil. They are important sources of vegetative nutrition in marine environment, providing major &amp; micro-nutrients required for sustenance of marine animals. Bacteria are also essential for the nitrogen cycle.</p> Signup and view all the answers

<p>A heterocyst is a specialized cell found in cyanobacteria, which fixes nitrogen.</p> Signup and view all the answers

<p>Cyanobacteria are a group of photosynthetic bacteria, commonly known as blue-green algae. They are important producers of oxygen in aquatic ecosystems and have a key role in the nitrogen cycle.</p> Signup and view all the answers

<p>Protists are a diverse group of eukaryotic organisms that are mostly unicellular, some are multicellular (algae). All protists are eukaryotic meaning that they have a nucleus, they are mostly aquatic and can be heterotrophic or autotrophic. Some protists live in moist soil or even in the human body.</p> Signup and view all the answers

<p>Plant-like protists are also known as algae. They are autotrophs and produce food from simple raw materials by photosynthesis. Animal-like protists are also known as protozoa. They are heterotrophs and get their food by engulfing other organisms. In both cases, protists can be free-living or parasitic.</p> Signup and view all the answers

<p>Although algae are autotrophic like plants, they don’t have true stems, roots or leaves.</p> Signup and view all the answers

<p>Chlorophyta = Mostly freshwater, unicellular and multicellular Phaeophyta = Marine, multicellular: large, brown algae found in kelp forests Rhodophyta = Mostly marine (many tropical), multicellular. 4000 species. Chrysophyta = Eukaryotic and single celled. Meet their nutritional needs through photosynthesis Pyrrhophyta = Eukaryotic single-celled algae and autotrophic. Many have two flagella, which allow the cells to be somewhat motile.</p> Signup and view all the answers

<p>Gamete formation (C)</p> Signup and view all the answers

<p>Fungus-like protists are heterotrophic organisms that absorb nutrients from dead or decaying matter. They resemble true fungi in appearance, but they lack fungal cell walls and are generally more mobile. They are an important part of the recycling of organic material in ecosystems.</p> Signup and view all the answers

<p>Cellular slime molds have a vegetative stage that is a haploid amoeboid cell, while acellular slime molds are multinucleate diploid amoeboid masses called plasmodium. Acellular slime molds reproduce sexually, while cellular slime molds can reproduce both sexually and asexually.</p> Signup and view all the answers

<p>Fungus-like protists (B)</p> Signup and view all the answers

<p>Zooflagellates are protists that move using flagella. Some are parasitic.</p> Signup and view all the answers

<p>Sarcodines are protists that move using pseudopodia, extensions of cytoplasm. They often engulf their food.</p> Signup and view all the answers

<p>Ciliates are protists that move using cilia, short hair-like structures. They can reproduce sexually or asexually.</p> Signup and view all the answers

<p>Sporozoans are protists that do not move. They are often parasitic and can cause diseases in humans and animals.</p> Signup and view all the answers

<p>Protista (A)</p> Signup and view all the answers

<p>Animals in the kingdom Animalia are eukaryotic, multicellular, heterotrophic, and, for the most part, lack cell walls.</p> Signup and view all the answers

<p>Platyhelminthes (C)</p> Signup and view all the answers

<p>The three main types of coelomates are acoelomates, pseudocoelomates and coelomates.</p> Signup and view all the answers

<p>Cnidarians are diploblastic, radially symmetrical animals that are mostly marine. They have a hollow space in the gastrovascular cavity and lack a head and central nervous system. They have distinct body forms during their lives, the polyp form is cylindrical, and the medusa form is bell-shaped. They have tentacles with stinging cells called cnidocysts to help them capture prey and defend themselves.</p> Signup and view all the answers

<p>Polymorphism is the occurrence of two or more distinct forms of an individual.</p> Signup and view all the answers

<p>Platyhelminthes are bilaterally symmetrical, dorsoventrally flattened organisms that are mostly parasitic. They have a distinct excretory system known as a flame-cell system to eliminate water and wastes, a well-developed reproductive system and are hermaphrodites, a central nervous system with a nerve cord and brain ganglion, and a digestive system with one opening for both ingestion and egestion.</p> Signup and view all the answers

<p>The three main classes of platyhelminthes are Turbellaria (free-living), Trematoda (flukes), and Cestoda (tapeworms).</p> Signup and view all the answers

<p>They are segmented (B)</p> Signup and view all the answers

<p>Annelids are bilaterally symmetrical, segmented worms, they have a true coelom and a complete digestive system. They have paired nephridia for excretion and a nervous system with a brain and longitudinal nerve cords.</p> Signup and view all the answers

<p>Metameric segmentation is a repetition of organs and tissues at intervals along the body of an animal.</p> Signup and view all the answers

<p>Arthropods are bilaterally symmetrical animals that have jointed appendages, a hard exoskeleton made of chitin, and a segmented body which is typically divided into a head, thorax and abdomen. Arthropods have specialized excretory, respiratory and nervous systems. They undergo metamorphosis, and they reproduce sexually or parthenogenetically.</p> Signup and view all the answers

<p>Chelicerata (B)</p> Signup and view all the answers

<p>Arachnids are characterized by having four pairs of legs, four pairs of eyes, a cephalothorax, which is a fused head and thorax, and book lungs for respiration.</p> Signup and view all the answers

<p>Crustaceans are mostly aquatic animals that have a hard exoskeleton made of calcium carbonate, two pairs of antennae and three pairs of mouthparts. They usually have gills for respiration, and their sexes are separate.</p> Signup and view all the answers

<p>Chilopods are mostly terrestrial animals that are carnivorous, they have a dorsoventrally flattened body and a head which contains two pairs of maxillae, one pair each of antennae, and a trunk made of 15-180 segments. Each segment has one pair of legs, except the first segment which has a pair of poisonous legs. Chilopods breathe through trachea and have malpighian tubules for excretion. They have genital organs which open at the posterior end of the body.</p> Signup and view all the answers

<p>Insects are the dominant class of arthropods on Earth, most insects have wings, they have a respiratory system composed of trachea and they undergo metamorphosis.</p> Signup and view all the answers

<p>Molluscs are soft-bodied, bilaterally symmetrical animals that typically have a shell, a mantle, a visceral mass and a foot. They are often aquatic but some live on land.</p> Signup and view all the answers

<p>The three main classes of molluscs are gastropods (snails and slugs), bivalves (clams, oysters, and scallops), and cephalopods (octopuses, squids, and cuttlefish).</p> Signup and view all the answers

<p>Cephalopods have a large and complex nervous system and are specialized for locomotion.</p> Signup and view all the answers

<p>Echinoderms are marine, triploblastic, unsegmented animals that are coelomates and deuterostomes. They have a radial symmetry, an endoskeleton composed of calcium carbonate, a water vascular system, and tube feet. They are ecologically important because they help to regulate the populations of other organisms.</p> Signup and view all the answers

<p>Chordates are bilaterally symmetrical, coelomate animals that have a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some stage in their development. They are the most advanced phylum and includes the vertebrates.</p> Signup and view all the answers

<p>Vertebrates have a vertebral column which is derived from the notochord, they have a well-developed brain protected by a skull, and they have a complex nervous system with a central nervous system. Most vertebrates have paired limbs or fins for locomotion and a circulatory system.</p> Signup and view all the answers

<p>The two main groups of fish are the lobe-finned fish and the ray-finned fish.</p> Signup and view all the answers

<p>Amphibians are a group of cold-blooded vertebrates that are mostly terrestrial, but they have adapted to life on land from aquatic ancestors, they have a moist smooth skin with no scales, and they have a three-chambered heart. They have a stage of metamorphosis where they transition from an aquatic larval form to terrestrial adult form, they breathe using lungs, gills and their skin, and they lay shelled eggs in the water.</p> Signup and view all the answers

<p>Mammals are warm-blooded vertebrates that are mostly terrestrial but there are some aquatic mammals. They have hair or fur, a four-chambered heart, and they give birth to live young except for monotremes. Mammals have mammary glands, which they use to feed their young.</p> Signup and view all the answers

<p>The three main groups of mammals are monotremes, marsupials, and placentals.</p> Signup and view all the answers

<p>Biomagnification (C)</p> Signup and view all the answers