Chapter 1: Intro to Living Things Diversity of Life Chapter 1: Intro to Living Things

Characteristics of Living Things All living things: Have organization Contain similar chemicals Use energy Respond to their environment Grow and develop Reproduce

Needs of Living Things All living things: Food Water Living space Stable internal conditions (homeostasis)

Taxonomy Domain – Eukarya Kingdom – Animalia Phylum – Chordata (vertebrata) Class - Mammalia Order - Primates Family – Hominidae Genus – Homo Species – sapiens

Important Terms Autotroph: producer; makes own food Heterotroph: consumer; cannot make own food Asexual reproduction: only one parent; identical offspring Sexual reproduction: two parents; genetic variation in offspring Prokaryote: unicellular organism without a nucleus Eukaryote: multicellular organisms with a nucleus

Diversity of Life Lesson 2.1 – Viruses

Viruses A virus is a tiny, nonliving particle that enters a living cell and reproduces in it. - nonliving - protein coat - genetic material (DNA) inside - cannot reproduce on their own

Viruses Viruses do not have many characteristics in common with living things, and are considered nonliving. A host is an organism that a virus enters and uses to reproduce. In this way, the virus is a parasite – almost always destroying the cells in which it enters.

Viruses Viruses are smaller than cells and must be magnified greatly to be seen. Some viruses are named for the disease they cause; others are named for where they were discovered.

Viral Multiplication 1. Virus attaches to host cell 2. DNA takes over many of the cell’s functions 3. Tells cell to produce the virus’s DNA and proteins 4. These assemble into new viruses

Viral Multiplication

Viral Structure Two basic parts: inner core with the DNA and a protein coat to protect it. Each virus has unique surface proteins, allowing them to attach only to certain cells. Think of a key fitting in a lock.

Viruses and Diseases Viruses can cause diseases in humans and other living beings. Plants and animals are able to be infected, as well. Some are mild, like colds, while other are much more series, such as HIV.

Usefulness of Viruses Viruses can be used in gene therapy to treat certain disorders, such as cystic fibrosis. Vaccine: substance introduced in the body to help produce chemicals that destroy specific viruses. Weakened/dead viruses are used to activate the body’s natural defenses in case the live virus enters it.

Usefulness of Viruses

Diversity of Life Lesson 2.2 – Bacteria

Bacteria Structure First found by Anton von Leeuwenhoek (remember: Cell Theory). Bacteria are single-celled prokaryotes (lacking nucleus). Most have cell wall and cell membrane to protect. The cytoplasm contains DNA and ribosomes. May also have a flagellum: whip-like structure to help in movement.

Bacteria Structure

Bacteria Shapes Three basic shapes, determined by the chemical makeup of the cell wall. Spherical Rod-like Spiral

Bacteria Shapes Three basic shapes, determined by the chemical makeup of the cell wall. Spherical

Bacteria Shapes Three basic shapes, determined by the chemical makeup of the cell wall. Rod-like

Bacteria Shapes Three basic shapes, determined by the chemical makeup of the cell wall. Spiral

Bacteria Sizes The largest bacterium is about the size of a period in a sentence in your book. Most are much smaller.

Obtaining Food Some are autotrophs . Some are heterotrophs. make food either through sun’s energy or from chemical substance in their environment. Some are heterotrophs. Must consume other organisms or foods made by organisms (milk, meat, decaying materials, etc.).

Respiration Recall that cellular respiration is the process of breaking down food to release energy. Most bacteria need oxygen, but some can break down food anaerobically (without oxygen). Aerobic – with oxygen; anaerobic – without oxygen

Reproduction Food, temperature, and other conditions allow bacteria to reproduce. Binary fission: asexual reproduction. One cell divides to form two identical cells. The cell doubles in size, duplicates its DNA, and splits. Increases the number of bacteria.

Reproduction Binary fission:

Reproduction Conjugation: sexual reproduction. One bacterium transfers some of its DNA into a second bacterium through a thin bridge. This process does not increase the number of bacteria. It results in bacteria that are genetically different from the parent cells.

Endospore Formation Forming endospores helps bacteria to survive harsh conditions. Endospore: small, rounded, thick-walled resting cells that forms inside a bacterial cell; protects DNA and some cytoplasm. Can protect bacteria for many years until conditions are suitable, when it opens up and allows the bacteria to grow and reproduce.

Bacteria in Nature Oxygen production: When an autotrophic bacterium undergoes photosynthesis, it releases oxygen into the air.

Bacteria in Nature Food production: bacteria can grow to create food such as cheese, pickles, and dairy products. Pasteurization is a process of heating food to a certain temperature that is high enough to kill harmful bacteria.

Bacteria in Nature Health and Medicine: bacteria help you digest food, obtain vitamins, and prevent harmful bacteria from making you sick. They are also used to make certain medicines and substances, such as insulin.

Bacteria in Nature Environmental Cleanup: some bacteria can clean oil spills and gasoline leaks in Earth’s land and water. Environmental Recycling: some bacteria are decomposers, or organisms that break down large, complex chemicals in dead organisms.

Diversity of Life Lesson 2.3 - Protists

Protists All are eukaryotes – organisms with a nucleus – and all live in moist surroundings. Other than this, they are very diverse. Some are multicellular, while others are unicellular. Some are autotrophs, some are heterotrophs, some are both. Some are immobile (cannot move), while others are mobile.

Animal-Like Protists Heterotrophs Most can move to get food Animal-like protists, called protozoans, are unicellular.

Types of Protozoans Sarcodines: form pseudopods (false feet) to help them move and eat. In fresh water, excess water can build up and cause the protozoa to burst. To prevent this, they have a contractile vacuole to collect and expel water. An amoeba is an example.

Types of Protozoans Sarcodines:

Types of Protozoans Flagellates: have flagella (whip-like structure) to help them move. Some may be helpful, as in the case of the termite example. The Giardia lives in fresh water, and when ingested by humans, can cause an intestinal condition.

Types of Protozoans Flagellates:

Types of Protozoans Ciliates: have cilia (hair-like projections) to help them move and eat. An example is the paramecium – has two nuclei and two contractile vacuoles.

Types of Protozoans Parasites: feed on cells and body fluids of their hosts. There are a variety of protozoans in this group. One example is the Plasmodium, which uses a mosquito and human hosts to transport malaria.

Plant-Like Protists Unicellular or multicellular Use pigments to capture the sun’s energy. Can be green, yellow, brown, red, orange, or black Plant-like protists, called algae, are autotrophs. Produce oxygen and are an important food source.

Plant-Like Protists Diatoms Unicellular Glasslike cell walls Float near surface or can attach to rocks Release a slime-like chemical to help them move Source of food for aquatic feeders

Plant-Like Protists Red Algae Almost all multicellular Red pigments absorb as much sunlight as possible in the depths of the ocean Nutrient-rich food

Plant-Like Protists Brown Algae Commonly called seaweed Holdfasts anchor algae to rocks like roots Stalks support blades Gas-filled sacs called bladders to help them float Used as a food source or thickener in foods.

Fungus-Like Protists Heterotrophs Have cell walls Use spores to reproduce Spore: tiny cell that is able to grow into a new organism Able to move at some point in life

Fungus-Like Protists Slime molds Colorful Live in moist, shady places (like forests) Feed on bacteria They begin as individual cells with pseudopods and can grow to be multicellular or unicellular with multiple nuclei Eventually grows and releases spores

Fungus-Like Protists Water molds and Downy mildews Live in water or moist places Often grow as tiny threads that look like fuzz Attack food crops

Diversity of Life Lesson 2.4 – Fungi

Fungi Eukaryotes Cell wall Heterotrophs that absorb food Reproduce using spores Grow in warm, moist environments

Fungi Cell Structure Unicellular or multicellular Most have their cells arranged in hyphae, branching tubes that make up the bodies of multicellular fungi. Substances can move through the hyphae Determines the physical characteristics of the fungi

Fungi Cell Structure

Obtaining Food Absorb food through hyphae that grow into their food source. Digestive chemicals comes from the hyphae into food, breaking it down and allowing it to become absorbed.

Reproduction Most reproduce both sexually and asexually They make spores that can be carried by wind and water to new areas, but only a few of these land in favorable areas. Spores are produced in fruiting bodies. These look differently in different fungus.

Asexual Reproduction When there is moisture and food, fungi make spores asexually. Cells in the hyphae divide to form identical spores. Unicellular yeast cells go through budding: no spores; small yeast cell grows from parent and then breaks away.

Sexual Reproduction If there are unfavorable conditions, the hyphae of two fungi grow together and DNA is exchanged. A new structure forms and produces spores that are a combination of the two fungi.

Reproduction

Classifying Fungi Three major groups classified by reproductive structures: Club Sac Zygote

Fungi in Nature Many are decomposers that break down the chemicals in dead organisms. This returns nutrients to the soil.

Fungi in Nature Yeast cells produce CO2 gas as they feed, creating bubbles in things like bread. Blue cheese and certain mushrooms are edible and used in several foods.

Fungi in Nature Alexander Fleming was growing bacteria in petri dishes and noticed mold growing in one dish; there was no bacteria growing near the mold. This led to the development of the first antibiotic, penicillin. An antibiotic is a substance that destroys bacterial cells.

Fungi in Nature Many are parasites for plants and animals. Results in huge crop losses every year. Athlete’s foot, ringworm, and other diseases are caused by the growth of fungus in humans.

Fungi in Nature In some cases, fungi growth in plants can help them grow. This relationship benefits both the plant and the fungi (mutualism). Lichen: a fungus and either algae or autotrophic bacteria that live together in a mutual symbiotic relationship.