Earth and Life Science - Q2 - Lesson 1 - PDF

EARTH and LIFE S E N I O R H I G H S C H O O L D E PA R T M E N T SCIENCE JEAIA A. ARIGUIN...

EARTH and LIFE S E N I O R H I G H S C H O O L D E PA R T M E N T SCIENCE JEAIA A. ARIGUIN Teacher I 0968-444-2675 [email protected] Introduction to Life Science At the end of the lesson the student will able to; Explain the evolving concept of life based on emerging pieces of evidence (S11/12LT-IIa-1) What Is Life Science? Life science studies life in all its forms, past and present. This can include plants, animals, viruses and bacteria, single-celled organisms, and even cells. Life sciences study the biology of how these organisms live, which is why you may hear this group of specialties referred to as biology. Different Branches of Life Science Biology – scientific study of life Anatomy – study of form and function, in plants, animals, and other organisms, or specifically in humans Botany – study of plant Microbiology – the study of microscopic organisms (microorganisms) and their interactions with other living organisms Different Branches of Life Science Cell biology (cytology) – study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell. Ecology – study of the interactions of living organisms with one another and with the non-living elements of their environment Genetics – the study of genes and heredity  How did life possibly start? What are the characteristics of living things?  How Did Life Begin Panspermia Life may have been seeded by life-forms from another planet  Panspermia is a hypothesis that suggests life on Earth originated elsewhere in the universe and was transported here. This idea proposes that microorganisms or organic matter were carried to our planet by comets, meteoroids, or other celestial bodies.  Extraterrestrial Origin: Life did not begin on Earth but was introduced from another location. Cosmic Transportation: Microorganisms or organic matter were carried to Earth by celestial bodies. Survival in Space: These life forms or their precursors could survive the harsh conditions of space, including radiation and extreme temperatures. Potential for Colonization: Upon reaching Earth, these life forms could have established themselves and evolved into the diverse organisms we see today.  How Did Life Begin Spontaneous Origin Life may have evolved from inanimate matter.  Spontaneous origin theory, also known as abiogenesis, was a historical scientific hypothesis that proposed that living organisms could arise from nonliving matter. 1This idea was prevalent for centuries, supported by observations like maggots appearing on decaying meat and mice appearing in stored grain.  How Did Life Begin Special Creation Life may have been placed on earth by supernatural/divine forces.  Special Creation Theory, also known as Creationism, is a belief that the universe, Earth, and all life on Earth were created by a supernatural deity or deities. This belief is often found in religious texts and traditions, particularly in Abrahamic religions like Christianity, Judaism, and Islam.  Life does not only involve the living things itself only but also includes its deepest characteristics. This is an important introduction on how you define a living and a non-living for you to simply know how important life is. 7 Basic Characteristics of Life: 1. Nutrition 5. Movement 2. Reproduction 6. Respiration 3. Excretion 7. Sensitivity 4. Growth  What are the earliest Cells? Prokaryotes have no distinct nuclear compartment to house their DNA. They are distinct from eukaryotes which their genetic material enclosed in a nucleus. The Common Ancestor of All Life All living things are made up of cells. Some are unicellular and some are multicellular. Unicellular organisms that are mostly known are paramecium, amoeba, bacteria, and yeast.  The multicellular cells include animal cells, plant cells, and the human body and germ cells. Given what scientists know about relationships among modern species.  What are common structures? 3. Nucleic acids – genetic material of a cell. 4. Ribosomes- factories that turn the information from nucleic acids into proteins. Unifying Themes in the Study of Life These refer to chemical structures that are composed of two or more atoms. MOSECELUL These are the basic working and structural unit of an organism. They are structured according to function. LCLES These are simply cells grouped together and performs a specialized function. TIESUSS  Unifying Themes in the Study of Life This this a body part or a part of an organism which is made up of a group of tissues. ROGAN These refer to the biotic and abiotic factors in an area. This includes not only the interaction between living things but also the interaction between living and nonliving. CEOYSSTEM Unifying Themes in the Study of Life Organelles. These are parts of the cell which are responsible for function and integrity. Some are membrane bound while others are not. Organism. This refers to the individual living species. Each thriving plant or animal is an organism. Population. These refer to all individuals of a species living in a specific area. Reproduction  In sexual reproduction, a male and female gamete is needed in order to produce an offspring. In most instances, there is a male and female organism to produce the gametes but, this isn’t always the case. Finding a partner for sexual animals can sometimes prove difficult, and so, as an adaptive mechanism and evolutionary solution, some animals exhibit hermaphroditism.  This is when an organism has both male and female reproductive system. This is common among sessile (stationary) animals. In hermaphroditism, the organism may or may not have a partner for fertilization to occur. Unlike, an asexual offspring, a sexual offspring is genetically unique from its parent organisms. Notice how there are two apparent sexes in sexual organisms, while there is no definite sex in the asexual organism. Types of asexual reproduction Binary Fission – occurs in single celled organisms. It is when a parent cell divides itself into two equal parts and create an offspring. This type of reproduction is like cloning. The word binary means something having two parts (the new daughter bacteria) while the word fission means the movement of splitting (the dividing of two equal parts). Ex. Bacteria 2. Fragmentation – occurs when an organism breaks a part of itself into a fragment, and the fragment develops into a new organism. Ex. Starfish & acoel flatworms 3. Budding – happens when a parent organism grows a bud attached to its body. When the bud is developed it will detach itself from the parent and form a new organism. Ex. Yeast and Jellyfish 4. Parthenogenesis – occurs when the embryo of an organism can grow and develop without fertilization. Ex. Some species of ants & Honeybees. Mechanisms of Fertilization There are two types of fertilization – internal and external. Internal fertilization occurs when the fusion of gametes is inside the female body, while an external fertilization is the opposite where fusion of gametes is outside the female body.  The 3 types of Internal fertilization 1. Oviparity – the female has fertilized eggs laid outside its body. The young will get nourishment from its yolk and will be protected by the external covering of the egg. The types of eggs will vary in different animals. Chicken eggs will have high calcium carbonate concentrations, while reptiles will produce leathery eggs. Ex. Chickens 2. Viviparity – most common in mammals, the offspring develops within the female and is nourished by the mother’s blood in the placenta. Ex. Bears 3. Ovoviviparity – like oviparity, ovoviviparity has fertilized eggs that nourish the young from its yolk. The key difference between them, is that ovoviviparous animals only lay the eggs when they are ready to hatch. Ex. Great White Sharks  Organisms have unique features that help them survive in their environment. Animals are designed to survive their environment through their form and function, and what better way to survive than to outsmart your predators and continue your species through reproduction. The male and female house bird will build a strong nest for its eggs to ensure that it will hatch and survive. The female lion will teach its young cub to hunt and protect it from predators when it is too young to defend itself.  The success of animal reproduction does not only end when an egg is fertilized. It ends when the offspring can fully grow and eventually reproduce as well. As mentioned before, reproduction is key to survival. We will all eventually die and we need to make sure that our species continue through reproduction. Factor #1: Predation In the animal kingdom exists a food chain. At the top of the food chain there are animals we call apex predators, while at the bottom of the food chain are animals that are weak and easily hunted by predators. Apex predators are animals that hunt and feed on other animals to survive and eventually reproduce. These predators are never or rarely hunted by any other animal.  On the other hand, since prey is easily hunted their offspring is always compromised and in danger. The success for preys to reproduce is greatly affected by the chances that these offspring get eaten when they are still young or developing. The connection of these animals in the food chain help maintain their progeny. Factor # 2: Environment To ensure a healthy offspring, the animal’s environment must also be nurturing to the young. Temperature greatly affects the development and the urges of an animal to mate. With the continuing rise of temperatures around the globe, some animals are starting to dwindle in number and die before they even reproduce.  When the water becomes too warm, the fishes will have a hard time getting oxygen and can eventually die when exposed to warm waters for longer periods of time. Glaciers and ice caps are melting in the arctic, causing polar bears suffer health conditions due to malnutrition. Factor # 3: Human Interaction Humans have been responsible for a lot of species extinction as we pose as one of the greatest threats to animals. Polluting land, water, and air; hunting; and deforesting are ways in which animal reproduction get disturbed. On the other hand, there are some human interventions that try to reverse these effects and attempt to save endangered species. Human Reproduction The first stages of Fertilization There are two ways in which the human female reproductive cycle can end – menstruation or pregnancy. If in the case it ends in pregnancy there are distinct stages before a baby is born. After copulation, when the sperm cell successfully merges with the egg cell, fertilization or conception happens. After 24 hours of the conception, the zygote or the fertilized egg undergoes a series of cell division also called the cleavage.  After cleavage, the zygote will undergo a series of growth divided into three trimesters, or in forty weeks, before the baby is born. BACARRA NATIONAL COMPREHENSIVE HIGH SCHOOL Senior High School Department