REVISION 1º ESO

UNIT 0

1.       Copy and complete…

The scientific method / observation / questions/ hypothesis / answer the questions / experiment / laboratory / experiment/ Petri disch / bunsern burner / beakers / flasks/ test tubes  / Results / Conclusions / Publication.

2.       Copy and complete…The scientific method • Scientists need to be strict about the methods they use and the way they communicate their results, so that other scientists can recreate their experiments.

UNIT 1

Summary 1.

 The Universe consists of matter, dust and energy grouped into stars forming galactic clusters. The Universe includes a galaxy called the Milky Way, which contains the Solar System, whose centre is the Sun. Consisting of planets: outer Jupiter, Saturn, Uranus, Neptune, inner Mercury, Venus, Earth and Mars. Dwarf planets are: Ceres, Pluto, Haumea, Makemake and Eris. Satellites, including the one belonging to the Earth, the moon, comets, asteroids and meteorites.

2.       Copy and complete the sentences.

The Universe: The Universe was formed 13.8 billion years ago after a huge explosion: the Big Bang. It is still expanding. Matter, space and time were created. The known matter in the Universe is formed of nebulae, stars, black holes and planetary bodies. According to scientists, this is just 5 % of the total matter in the Universe. The rest is dark matter and we do not know what it is like as we cannot see it. Stars and galaxies: Stars shine because nuclear reactions take place in them. This produces lots of energy. Stars are grouped into galaxies. In the Universe there are hundreds of billions of galaxies. Each one contains billions of stars. Stars form in a nebula. They are made of gases and cosmic dust. The Solar System: The Solar System is located in the Milky Way galaxy and is made up of a central star, the Sun, and planetary bodies that revolve around it; planets, natural satellites, comets and asteroids. There are eight major planets. The four interior planets are small and rocky and the exterior planets are big and gaseous, some with ring systems. The natural satellites (Moons) orbit around the planets. Their number varies, for example Earth has one moon and Jupiter has 67. Comets become more visible as they get closer to the Sun as their distinctive tail can be seen. Comets have elliptical orbits. Asteroids are found mainly in the asteroid belt between Mars and Jupiter. When a fragment of an asteroid hits a planet or satellite it is called a meteorite and it can leave behind an impact crater. Has the Universe always been the same? Since the beginning, with the occurrence of the Big Bang, the universe has been changing. The Universe is not static; it evolves. During the life of the Universe planets and other celestial bodies have been created and destroyed. It is also known that nowadays the universe is expanding. There are many theories about the future of the Universe: a) Big Crunch: the metric expansion of the Universe will eventually reverse and the universe will collapse, ultimately ending as a black hole.  b) Heat Death: in which the universe will diminish to a state of having no thermodynamic free energy, and therefore will no longer be able to sustain processes that consume energy. c) Big Rip: In conclusion, the theory suggests that galaxies and galaxy clusters will be split apart due to the ever-expanding Universe.

Page 55

1.       Copy and complete the concept map:

 • The Earth - has a satellite - the moon - which appears in different phases - new moon - first quarter - full moon - last quarter • The Earth - has a satellite - the moon - which affects the Earth - tides - spring • The Earth - has a satellite - the moon - which affects the Earth - Eclipse - lunar • The Earth - moves - rotation -on its axis - which causes - day • The Earth - moves - orbit - around the sun - which causes - seasons.

2.       The movements and position of Earth in space

 The Earth rotates on its axis once every 24 hours, causing day and night. At the same time it revolves around the Sun, which takes 365 days, 6 hours and 9 minutes. The Earth rotates in an anti-clockwise direction and its rotational axis is tilted 23º 27' (27 minutes) with respect to the elliptic plane. The inclination of the Earth’s rotational axis causes the seasons and also makes the number of hours of daylight change during the year. The highest number of daylight hours is on the day of the summer solstice and the lowest number is on the day of the winter solstice. The Moon The Moon is the only satellite of the Earth and completes its orbit in about 28 days. It also takes this time to rotate on its own axis. The Earth and the Moon We see the Moon from the Earth as different shapes as it revolves around us and these shapes are called phases. The main phases of the Moon are: first quarter, full moon, last quarter and new moon. Tides are the periodic rise and fall of sea levels and are due to the gravitational attraction of the Sun and Moon. When the Earth, Moon and Sun are aligned, the gravitational attraction of the Sun and Moon combine to produce spring tides. Neap tides occur in the opposite case. Eclipses occur when the Earth, Moon and Sun are aligned. Solar eclipses only occur during a new moon and they can be total, partial or annular.

Page 75

 The Geosphere 1.

 Copy and complete the concept map:

 -the Earth's crust - is made up of - continental crust -the Earth's crust - is made up of - crusts - which are formed with - minerals  -the Earth's crust - is made up of - crusts - which are formed with - minerals -that have properties including - density-the Earth's crust - is made up of - crusts - which are formed with - minerals -that form - rocks - that may be - igneous - that may be - plutonic -the Earth's crust - is made up of - crusts - which are formed with - minerals -that form - rocks - that may be - sedimentary -that may be - saline/limestone -the Earth's crust - is made up of - crusts - which are formed with - minerals -that form - rocks - that may be – metamorphic

 2. Copy and complete the statements:

 The structure and composition of the Earth • The Earth is composed of three layers: the crust, mantle and core.  • There are two types of crust: continental and oceanic. • The most abundant element in the Earth is iron. Minerals • Minerals are solids that are formed in nature. They have a fixed chemical composition and internal crystalline structure. • The shape and size of the crystals depend on how they were formed. Large crystals form when they have time and space to grow. • Minerals have physical properties, which can be used to identify them: hardness, density, colour, lustre and so on. • Minerals can be used to obtain metals and in jewellery. They are also the raw material for a huge range of manufactured products. Rocks • Rocks are made of minerals. They are generally made up of more than one type, but some rocks consist of only one. • Rocks are classified into three types: sedimentary, igneous and metamorphic. • Sedimentary rocks are formed on the Earth’s surface from eroded particles, dissolved salts and the remains of organisms. • Igneous rocks are formed from magma. If it solidifies deep in the Earth, it forms plutonic rocks; if it solidifies on the surface as lava, it forms volcanic rocks. • Metamorphic rocks are rocks that were transformed deep underground by high pressure, high temperatures, or both. • Coal and oil come from organic remains that have been buried and transformed by the action of bacteria. • Rocks are used in construction and road building and as raw materials for industry.

Page 93

 The atmosphere

1.       Copy and complete the concept map:

 The Atmosphere - is a - layer of gases - formed by nitrogen - oxygen - other gases The Atmosphere - is a - layer of gases - divided into vatious layers - troposphere - stratospheremesosphere - ionosphere/thermosphere - exosphere The Atmosphere - is affected by - pollution - produced by - human activity The Atmosphere - is affected by - pollution - pollution effects - the enironment - acid rain - smog The Atmosphere - is what produces - atmospheric phenomena - which include - wind - greenhouse effect - clouds - precipitation 2. Copy and complete the sentences (gaps in italics): • The atmosphere is the gaseous layer that surrounds the Earth. Atmospheric air is made up of a mixture of gases, mainly nitrogen (78%) and oxygen (20.9%). The atmosphere has different layers depending on altitude: the troposphere, stratosphere and ionosphere, in which gas concentration decreases with altitude and the temperature varies.  • The troposphere is the layer in contact with the Earth's surface. Clouds form there and weather conditions occur: wind, rain, snow, etc. • The atmosphere allows life to exist on the Earth's surface as it protects us from the Sun's heat, prevents dangerous radiation from reaching us and contains oxygen and carbon dioxide, which are necessary for respiration and photosynthesis. • Natural processes and human activities, especially the use of fossil fuels, produce substances that can damage the quality of the air and harm people and property. In cities, these contaminants can cause a dense fog known as smog. They can also get into the water droplets that form clouds and fall to the ground in rainwater, causing acid rain. • The atmosphere contains gases that prevent all of the heat from the Sun escaping overnight. They are called greenhouse gases. In recent years, due to human activity, large amounts of these gases are being released into the atmosphere, creating global warming that can lead to climate change. To avoid this gradual warming, a large number of countries have signed an international agreement, the Kyoto Protocol, promising to reduce emissions of these gases.

ASWER THE INITIAL QUESTION

 The atmosphere of the Earth is unique in the Solar System as it creates conditions on the planet that are suitable for living things to exist. It blocks out solar rays, creates the wind that drives the water cycle and provides the gases needed for life, oxygen and carbon dioxide. It also traps in heat to create a climate suitable for life to exist.  Other planets in the Solar System do have atmospheres, but none of these create conditions that are as suitable for life as the atmosphere of the Earth.

Page 109

1. The missing words, from top to bottom, are as follows: Water Fresh water Anthropogenic Groundwater

2. The sentences can be completed as follows: The hydrosphere ■ The hydrosphere consists of all the water on Earth: seas and oceans, continental runoff, groundwater and glaciers. ■ Liquid water has made it possible for life to develop on our planet. Water is the main component of living things. It constitutes 70% of our bodies and in many organisms it is as much as 95%. ■ Water is essential for living things, because many organisms live in it. Water dissolves and carries substances needed for cell nutrition and eliminates waste substances that organisms expel in urine and sweat. Plants need water for photosynthesis and other biochemical reactions. Water pollution ■ Water pollution can be anthropogenic or from natural causes. Water is polluted by urban waste or industrial, agricultural or livestock waste. Water treatment ■ Water is a fixed resource and larger amounts are increasingly needed, mainly because the world population is growing. For this reason, we need to: – Use water responsibly and reuse it, and not waste it or pollute it. – Purify water so that we can drink it. – Treat contaminated water so we can reuse it. ANSWER THE INITIAL QUESTION Water can be found in three states:  Gas in the clouds; liquid in lakes, seas, rivers and oceans; and solid in ice and snow.

Page 131

1. Copy and complete: – Living things / main function / provide energy to perform life processes / which are / nutrition, reproduction, and interaction. – Living things / biomolecules / examples / carbohydrates, lipids, and proteins. – Biomolecules / found in cells / form tissues / form organs / form systems / form organisms. – Biomolecules / types / prokaryotic / eukaryotic / plant cell and animal cell.

2. Copy and complete:

The main element that living things are made up of is carbon. Other elements are oxygen, hydrogen, nitrogen, sulphur and phosphorous. – The main biomolecules are lipids, carbohydrates, proteins and nucleic acids. They provide energy, produce chemical reactions, repair damaged tissue and help to form other biomolecules and tissues. – The life processes of living things are nutrition (autotrophic or heterotrophic), reproduction (sexual or asexual) and interaction, which means receiving stimuli and responding to them.

Characteristics of cells – A cell is the simplest unit of an organism. There are unicellular organisms (one cell performs all the jobs) and multicellular organisms (each cell specialises in a function). – Most cells are so small that we need to use an optical or an electron microscope to see them. – Cells are surrounded by a cell membrane. The cytoplasm, where organelles can be found, is inside the membrane. There are membranous organelles such as the nucleus, the endoplasmic reticulum, the Golgi apparatus, the lysosomes, the mitochondria, the vacuole and the chloroplasts. Organelles like ribosomes, centrioles and the cytoskeleton are nonmembranous. – Cells can be divided into prokaryotic and eukaryotic cells, depending on their structure. Bacteria are an example of prokaryotic cells, which have no membranous organelles. In eukaryotic cells, genetic material can be found in the nucleus, and the organelles are in the cytoplasm. Animal and plant cells are eukaryotic. – Specialised cells, which have a specific function, combine to form tissues, which work together to form organs. Organs work together in systems that together form an organism.

ANSWER THE INITIAL QUESTION ■ Living things are made up of organic matter. The key chemical element of organic matter is carbon. Other elements that are abundant in organic matter are oxygen, hydrogen, and nitrogen. Living things are made up of biomolecules, whose main functions are to provide the energy to perform the life processes, to participate in chemical reactions, and to form and repair cell tissues. There are three types of biomolecules: lipids, carbohydrates and proteins.  Biomolecules can be found in cells. A group of cells form a tissue, a group of tissues form an organ, a group of organs form a system, and a group of systems form an organism.

1.       Copy and complete the concept map… The concept map can be completed as follows, with the correct words indicated in italics: – Living things / must have cells which can be / prokaryotic / which has two domains / bacteria and archaea / which together comprise one kingdom / Monera. – Living things / must have cells which can be / eukaryotic / belong to the domain / Eukarya / which has four kingdoms / Fungi / mushrooms, mould and yeast / Animalia / all animals / Plantae / all plants /Protista / algae and protozoa / lichens. 2. Copy and complete the sentences…

2.        The sentences can be completed as follows: Biological evolution and biodiversity ● The theory of biological evolution states that species change over time to adapt to new environments. These changes are caused by genetic changes called mutations. Species that do not adapt to new environmental conditions become extinct. ● Biodiversity refers to the number and variety of species. Protecting it is vital to the survival of our species because all living things depend on each other. ● We use binomial nomenclature to classify and identify organisms. This avoids confusion and ensures that each organism has its own unique two-word name.  ● Living things are grouped into three domains: Archaea, Bacteria and Eukarya. The Eukarya domain comprises four kingdoms: Protista, Animalia, Plantae and Fungi. ● Living things can also be grouped according to the type of cells they have (prokaryotic or eukaryotic), how they get nutrition (autotrophic or heterotrophic) and whether or not they have tissue. Less complex living things ● Bacteria are organisms that have not evolved much. They are prokaryotes and can be autotrophic or heterotrophic. Some of them cause diseases while others are very beneficial.  ● Protists include protozoa and algae. There are many types of protozoa. Some are parasites but most are harmless. Algae are autotrophic organisms; they can carry out photosynthesis. They can be unicellular or multicellular. ● Fungi are heterotrophic organisms that, along with certain bacteria, play a very important role in the natural recycling of organic matter. This group includes mushrooms, moulds, yeasts and lichens. ● Some moulds, for example, Penicillium, are important to the natural environment, and to the production of food and medicines. ● Lichens are actually organisms formed by the symbiosis of unicellular algae and fungi. ANSWER THE INITIAL QUESTION The origin of biodiversity is biological evolution. This refers to the gradual change of existing organisms into different species due to environmental pressures through the process of natural selection. Living things can be grouped into three domains (Archaea, Bacteria and Eukarya) which contain the traditionally used five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia. STUDY SKILLS Use the quick revision boxes.

1. Copy and complete: Plants / are divided into various groups / non-vascular plants / vascular plants / non-seed producing plants / seedproducing plants/ gymnosperms / conifers, gingkoes, cycads/ angiosperms/ monocotyledons / dicotyledons.

2. Copy and complete: Plants – Plants originated from green algae and gradually adapted to life on land. – Plants are living organisms that absorb energy from sunlight and transform it into organic matter in a process called photosynthesis. – They are usually fixed to the ground by roots, which have hairs that absorb water and mineral salts. – Native or indigenous plants occur naturally in different places with the same environmental conditions. However, endemic plants are specific to only one particular place. Non-native plants can become invasive if they cause other plant species that are indigenous to the area to disappear. – Plants have acquired a great variety of characteristics that enable them to survive in diverse environmental conditions, such as extreme conditions of drought or floods. Types of plants – Plants can be classified according to their degree of evolution as bryophytes, pteridophytes, gymnosperms and angiosperms. – Bryophytes have evolved very little and have no vascular tissue. They live in humid areas and play an important role in the formation of fertile soil. This group includes mosses. – Pteridophytes are plants that have vessels, roots, stems and fronds. This group includes lycopods andferns. – Plants with seeds are classified into two groups: - Gymnosperms: these have seeds that are not protected by a fruit. This group includes conifers such as pines and firs. - Angiosperms: these have seeds that are protected by a fruit and have colourful flowers. They can be classified either as monocotyledons or dicotyledonsThe ability to produce their own organic matter makes plants special and vital for the existence of living things. They have colonised the majority of the Earth’s ecosystems. They are vital for life because they produce oxygen and absorb dioxide of carbon, maintaining the temperature of the Earth constant

SUMMARY 1. Invertebrates / consist of / Sponges / cnidarians / which include / jellyfish and polyps Plathelmynthes / which include / tapeworm / planaria Nematodes / which include / trichinella worms / anisakis worms Annelids / which include / earthworms/ Molluscs which include / gastropods / which includes / snails / bivalves / which include / mussels / cephalopods / which include squid. Echinoderms / which include / starfish Arthropods / which include / arachnids / which include / spiders / crustaceans / which include / prawns / myriapods / which include / centipedes / insects which include / butterflies. 2. The correct words are in italics The simplest invertebrates – Sponges and cnidarians are the simplest aquatic animals. – Cnidarians are aquatic animals and can be either polyps or jellyfish. – Platyhelminthes are flatworms which include the tapeworm. Nematodes are roundworms which include the harmful Trichinella genus. Annelids, molluscs and echinoderms – The bodies of annelids are composed of rings. Examples are lugworms, earthworms and leeches. – Molluscs are soft-bodied animals with highly developed sensory organs. The most important molluscs are gastropods, bivalves and cephalopods. – Echinoderms are marine animals characterised by their external skeleton and their ambulacral system. The most important are starfish, sea urchins and sea cucumbers. Arthropods  – The bodies of arthropods are covered by an exoskeleton.  – They have segmented bodies consisting of a head, thorax and abdomen. They also have jointed appendages such as wings, legs, antennae and mouthparts. – Arachnids have a body that is divided into a cephalothorax and an abdomen. They have no antennae or mandibles, but have six pairs of appendages. The most representative arachnids are spiders and scorpions. – The bodies of myriapods are made up of many jointed appendages. The best known myriapods are centipedes, such as scolopendridae, and millipedes, such as Julus terrestris.  – Crustaceans are divided into lower and upper groups. The lower crustaceans are microscopic and form part of zooplankton. Higher crustaceans have a hard shell, two pairs of antennae, a chewing mandible and five pairs of legs. Examples are freshwater crayfish, prawns and crabs, among others. – Insects are the most biologically successful arthropods. They have a pair of antennae, mouthparts adapted to different ways of feeding, three pairs of legs and one or two pairs of wings. Their biological success is due to their small size, ability to fly and the high number of eggs that they produce. Answer the initial question Invertebrates dominate every ecosystem. The invertebrates constitute more than 95% of the species on Earth. They are key elements in the food chain as herbivores, predators, parasites and decomposers.  They are food for mammals, birds, reptiles, fish, and other invertebrates. Invertebrates benefit the ecosystem by means of pollination, soil formation and aeration, decomposition and seed dispersal.

Summary 1. Vertebrates / fish / bony / tuna and anchovies Cartilaginous / sharks and skates Amphibians / anurans / frogs and toads Urodeles / salamanders and newts Reptiles / lizards and saurians, chelonians, ophidians, crocodilians Birds/ flightless birds/ ostriches and emu /  Waterfowl birds / penguin and cormorants Climbing birds / parrots and woodpeckers Wading birds / storks and flamingos Birds of prey / owls and falcons Game birds/ grouse and pheasants. Mammals /rodents / squirrels and beaver Cetaceans / whales and dolphins Primates / monkeys and humans Ungulates / horses and giraffes Chiropteran / bats and flying foxes Insectivores / hedgehogs and shrews.

Initial question

Vertebrate have characteristics that make them different from other animals. For example they have bilateral symmetry. They have an internal skeleton which is made of cartilage or bone. The spinal column protects the spinal cord. They also have limbs

Page 221 Summary 1. Complete the concept map: – Photosynthesis - which needs - water - which, together with nutrients, is absorbed from the soil by the roots. – Photosynthesis - which needs -  carbon dioxide which is captured through the - stomata. – Photosynthesis - which needs -sunlight - which is absorbed through - leaves - which store this energy in – chlorophyll. – these combine to make - glucose - which is converted into - starch. – these combine to make - oxygen - which is released into - the atmosphere.

2. Copy and complete the sentences: Photosynthesis, nutrition and respiration of plants • Plants absorb sunlight energy in their chlorophyll and use carbon dioxide and water to turn it into glucose and oxygen. • Plants use the glucose to produce the nutrients they need. The oxygen is released into the air. • Chlorophyll is a pigment found in the chloroplasts of plants and algae. • Respiration is the process through which living things release the energy contained in biomolecules. The exchange of gases that takes place in respiration is the opposite of photosynthesis. When plants respire, they take in oxygen and release carbon dioxide. • The main function of leaves is photosynthesis and their structure is adapted to this function. Leaves have a waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll and lower epidermis. They also have stomata and vascular vessels. Plant nutrition • Plant roots absorb water and minerals through root hairs by a process called osmosis. • Carbon dioxide enters the plant through the leaf stomata. Soil minerals provide bioelements to manufacture proteins and cellular structures. • Plants have two systems for transporting substances. These are called the xylem and the phloem systems. The xylem system transports water upwards from the roots to the leaves through a process called transpiration. The phloem system transports sap from the leaves to the rest of the plant. Agriculture • Farmers use chemicals to achieve higher yields. These include pesticides, which attack insects and other pests, herbicides, which kill weeds, and fertilisers. Fertilisers are mixture of chemicals used to enrich the soil and promote plant growth.

Page 237 Animal nutrition 1. Complete the concept map

 - animal nutrition / consists of four processes / digestion / converts food into nutrients / it can be / extracellular / in / most vertebrates and invertebrates - animal nutrition / consists of four processes / circulation / carries nutrients around the body / it can be / closed / in / annelids and vertebrates - animal nutrition / consists of four processes / respiration / uses oxygen to correct nutrients into energy / it can be : - branchial / in / fish - pulmonary / in / vertebrates - animal nutrition / consists of four processes / excretion / removes waste from the body / it can use / kidneys, respiratory organs and sweat glands / in / mammals

 2. Complete the sentences

 The digestive, circulatory, respiratory and excretory systems are involved in nutrition. • Digestion is the conversion of food into nutrients, which provide energy and components for cellgrowth and renewal. • The circulatory system includes the heart, which pumps blood through the blood vessels. It transports nutrients and oxygen to cells and carries waste from the cells to the excretory organs. • The hearts of birds and mammals consist of two pumps that work together. One pumps blood to the lungs, where carbon dioxide is released and oxygen is collected, while the other pumps oxygenated blood to the other organs. • In cellular respiration, energy is released from nutrients in the presence of oxygen. This energy is then used by the cells. • The different types of respiration are: cutaneous (e.g. the earthworm), tracheal (e.g. insects), branchial (e.g. fish) and pulmonary (e.g. amphibians, reptiles, birds and mammals). • The waste produced during cellular activity is removed through a process called excretion. This waste would be toxic if it was allowed to accumulate. • The kidneys of vertebrates filter blood and remove excess water, salts and waste in the form of urine. The lungs expel carbon dioxide. • In mammals, the sweat glands of the skin also remove waste substances.

Page 255  Living things interact 1. Copy and complete the concept map: Interaction - animals - respond to - stimuli - through - sensory receptors - neurons -nervous system - spinal cord - response - behaviour - Innate behaviour. Interaction - plants - respond to - stimuli - response - tropisms - slow -e.g. - phototropism/geotropism Interaction - plants - respond to - stimuli - response - nastic movements

2.Copy and compete the sentences

 Animals respond to stimuli • A stimulus is an external or internal factor that provokes a response in an individual. • Receptors are specialised cells that detect stimuli and transmit them to the nervous system and the endocrine system. Together, they form the sense organs, which are located principally in the upper, front part of the body. • The vertebrate nervous system consists of the brain, spinal cord and nerves. The brain is the main coordination centre. Neurons are the main cells in the nervous system. They transmit nerve impulses all round the body. • Innate behaviour is present from birth and does not need to be learnt. Learnt behaviour has to be acquired. A reflex action is a rapid, automatic response to a stimulus. • The nervous and endocrine systems coordinate an individual’s responses and regulate its internal functioning. • The endocrine system is a coordination system in animals, which operates using chemical signals, hormones, which are produced by endocrine glands in response to specific stimuli. Hormones are released into the bloodstream and act in a specific way on certain tissues or organs. Plants respond to stimuli • Tropisms are the directional responses of plants to external stimuli such as light, gravity or contact. They are controlled by the plant hormone called auxin. • Plant hormones regulate many processes that take place in plants: growth, the loss of leaves in autumn, flowering, the production and ripening of fruit, etc. • Nastic movements are non-directional responses produced in plants by an external stimulus.

Page 271  Plant reproduction 1. Copy and complete the concept map:

 - Plant reproduction - can be - asexual - through -underground stems - tubers - potato - Plant reproduction - can be - asexual - through underground stems - bulbs - tulip - Plant reproduction - can be - asexual - through underground stems - rhizomes - bamboo - Plant reproduction - can be -sexual - through flowers - gymnosperms - produces seed cones - pine - Plant reproduction - can be -sexual - through flowers - angiosperms - produces normal flowers orchid. 2. Copy and complete the sentences (gaps in italics): Reproduction and its objective Reproduction is a life process of organisms that enables them to create living things from pre-existing ones. It allows for the indefinite continuation of the species. There are two types of reproduction. In asexual reproduction, offspring are identical to parents because they develop from a fragment, a spore, a bud or parent bipartition or division. In sexual reproduction, two different cells from different individuals come together to create a zygote from which, by successive cell divisions, an embryo and then a new organism originates with different characteristics from those of their parents. Reproduction in plants As with some less evolved animals, plants have the peculiarity that throughout their life cycle they alternate between two different organisms. The gametophyte creates gametes, which join to form a zygote of the sporophyte. The sporophyte creates spores from which the gametophyte originates. This feature in plants is called alternation of generations. The flower as reproductive organ More highly evolved plants have reduced gametophytes to a small number of cells located in the stamens and carpels of flowers. The male gamete goes a long way from the stigma, or top of the pistil, to reach the female gamete located inside the ovary at the base of the pistil. Pollination In order for pollen grains to reach the female organs of the flower, they must be carried by bees, other insects, small birds or the wind. Pollination can occur through self-pollination or crosspollination.

Page 289  Summary 1. Complete the concept map (gaps in italics) types - asexual - no fertilisation - invertabrates types - sexual - fertilisation - internal types - sexual - fertilisation -external - bony fish -anura amphibians - frogs/toads embryo development - ovoviviparous - oviparous viviparous – mammals

Copy and complete the sentences:

Types of animal reproduction Asexual reproduction allows animals to produce many individuals that can expand into new territories quickly. In sexual reproduction, a gamete from a male and a female are needed. This type of reproduction producesgenetic variation in offspring. Gametes are formed in the reproductive organs, or gonads. Males have testicles and they produce sperm. Females have ovaries that produce ova.  Fertilisation in animals can be external or internal. We classify animals according to the development of its embryo into oviparous, viviparous and ovoviviparous animals. Parthenogenesis is a special form of reproduction in which the embryo is formed from an ovum without fertilisation. The development of a new organism can be direct as in most oviparous and viviparous animals, or indirect as in butterflies and frogs, which go through a process called metamorphosis before becoming adults. Fish and amphibian reproduction Cartilaginous fish reproduce through internal fertilisation. Bony fish have external fertilisation and they are oviparous. Urodele amphibians have internal fertilisation and are oviparous. Anuran amphibians have external fertilisation. They are oviparous ad their tadpoles undergo metamorphosis Reptile, bird and mammal reproduction Reptiles have internal fertilisation and are usually oviparous. Birds have internal fertilisation. They are oviparous and they incubate their eggs. The eggs of both reptiles and birds have a protective shell and membrane. Mammals have internal fertilisation and most of them are viviparous. The mother and the foetus exchange substances through the placenta. The gestation period is the time between fertilisation and birth. Young mammals feed on milk secreted by the mother’s mammary glands.

Summary 1. Complete the concept map) types - asexual - no fertilisation - invertabrates types - sexual - fertilisation - internal types - sexual - fertilisation -external - bony fish -anura amphibians - frogs/toads embryo development - ovoviviparous - oviparous viviparous – mammals

2.       Copy and complete the sentences: Types of animal reproduction Asexual reproduction allows animals to produce many individuals that can expand into new territories quickly. In sexual reproduction, a gamete from a male and a female are needed. This type of reproduction producesgenetic variation in offspring. Gametes are formed in the reproductive organs, or gonads. Males have testicles and they produce sperm. Females have ovaries that produce ova.  Fertilisation in animals can be external or internal. We classify animals according to the development of its embryo into oviparous, viviparous and ovoviviparous animals. Parthenogenesis is a special form of reproduction in which the embryo is formed from an ovum without fertilisation. The development of a new organism can be direct as in most oviparous and viviparous animals, or indirect as in butterflies and frogs, which go through a process called metamorphosis before becoming adults. Fish and amphibian reproduction Cartilaginous fish reproduce through internal fertilisation. Bony fish have external fertilisation and they are oviparous. Urodele amphibians have internal fertilisation and are oviparous. Anuran amphibians have external fertilisation. They are oviparous ad their tadpoles undergo metamorphosis Reptile, bird and mammal reproduction Reptiles have internal fertilisation and are usually oviparous. Birds have internal fertilisation. They are oviparous and they incubate their eggs. The eggs of both reptiles and birds have a protective shell and membrane. Mammals have internal fertilisation and most of them are viviparous. The mother and the foetus exchange substances through the placenta. The gestation period is the time between fertilisation and birth. Young mammals feed on milk secreted by the mother’s mammary glands.