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Explore the interconnectedness of ecosystems and the components that sustain life within them, including energy, organisms, and abiotic factors. Learn about the levels of ecological organization, from individuals to populations, communities, and habitats. Understand the impact of natural selection on evolution, inspired by Charles Darwin's observations on traits that lead to successful adaptation in varied environments.
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Chapter 4 – The organization of life Section 1 – Ecosystems: Everything is Connected
Defining an Ecosystem • Ecosystem: Communities of organisms and their surrounding environment • - oak forest or a coral reef • Ecosystems are connected • a. Do not have clear boundaries • b. Things move from one ecosystem to another • - Pollen can blow from a forest into a field • - Soil can wash from a mountain into a lake
Ecology • Ecology: the branch of biology that deals with the relations of organisms to one another and to their physical surroundings.
The Components of an Ecosystem • - Ecosystems need five basic components to survive: • 1. energy (most comes from the sun) • 2. mineral nutrients • 3. water • 4. oxygen • 5. living organisms. • - If one part of the ecosystem is destroyed or changes, the entire system is affected
Biotic and Abiotic Factors • - Biotic factors • - environmental factors that are living or once living organisms OR materials that come from organisms • - plants, animals, dead organisms, and their waste products • - Abiotic factors • - environmental factors that never were living organisms • - air, water, rocks, and temperature, etc.
Ecologists organize life into categories Organism: Living things that can carry out life processes independently. • -You are an organism, as is an ant, ivy plant, and each of the bacteria living in your intestines. • - Every organism is a member of a species. • -Speciesare groups of organisms that are closely related and can mate to produce fertile offspring. (Mating pair)
Ecologists organize life into categories • - Members of a species may not all live in the same place. Field mice in Maine will not interact with field mice in Texas • - Populations • - groups of organisms of the same species that live in a specific geographical area and interbreed. • - All the field mice in a corn field make up a population of field mice.
Ecologists organize life into categories • - Members of a population usually breed with one another rather than with members of other populations • - Bison will usually mate with another member of the same herd not other a member from another herd
Ecologists organize life into categories • Communities: Groups of various species that live in the same habitat and interact with each other • - Every population is part of a community • - The most obvious difference between communities is the types of species they have. • - Land communities are often dominated by plants species • - The plants determine what other organisms can live in that community
Ecologists organize life into categories • Habitat: Places where an organism usually lives • - Habitats have specific characteristics that the organisms living there need to survive • - If any of these factors change, the habitat changes • - Organisms tend to be very well suited to their natural habitats • - animals and plants usually cannot survive for long periods of time away from their natural habitat
Ecologists organize life into categories • Ecosystem: Communities of organisms and their surrounding environment • Biome: a large region with a similar climate and organisms • Biosphere: the regions of the surface, atmosphere, and hydrosphere of the earth occupied by life.
Organism Research Project • Pick an Organism and research the following information about the organism: • Common Name, Scientific Name, Name of a group of your organism (ex: Group of lion = Pride, sault, or troop) • Other populations that interact with this species • Detailed description of natural Habitat (include some specific biotic and abiotic factors in description) • Regional location (be specific as possible) and Biome (include climate details) the organism is primarily located • Create a mini-poster with all of this information. Include a colored drawing of your organism in an example of it’s habitat.
-Turn in: Ecosystem Drawing and Organism Poster. -Get a Evolution Note handout. What do you think? What are some adaptations organisms have to hunt prey? What are some ways organisms defend for themselves from hunters? Chapter 4 – The organization of life Section 2 - Evolution
Charles Darwin • - Charles Darwin observed that organisms in a population differ slightly from each other in form (structure), function, and behavior • - Some of these differences are hereditary (get passed from parent to offspring) • - He proposed the environment exerts a strong influence over which individuals survive to produce offspring • - Some are more likely to survive and reproduce than other individuals because of certain traits
Evolution by Natural Selection • - Natural selection: individuals that have favorable traits and are better adapted to their environment. • -They survive and reproduce more successfully than less-adapted individuals • - Darwin proposed that over many generations, natural selection causes the characteristics of populations to change • - Evolution: change in the characteristics of a population from one generation to the next. AKA “decent with modification”
Nature Selects • - Nature ‘selects’ for certain traits, such as sharper claws, because organisms with these traits are more likely to survive • - Over time, the population includes a greater and greater proportion of organisms with the beneficial trait • - As the populations of a given species change, so does the species.
NS = some of each SS = sickle cells NN = normal cells Sickle Cell Anemia • In the heterozygous condition, both alleles are expressed equally • Example: Sickle Cell Anemia in Humans sick http://www.youtube.com/watch?v=1fN7rOwDyMQ
Nature Selects • Adaptation: an inherited trait that increases an organism's chance of survival and reproduction in a certain environment • -Can be an Physical, Behavioral, or Physiological change that improves a population’s ability to • survive
Three Types of Adaptations • Physical Adaptations: some type of structural modification made to a part of the body. • Ex: webbed feet, sharp claws, fur. • Behavioral Adaptations: something an animal does (how it acts) usually in response to some type of external stimulus. • Ex: hibernation, mating dances, flying south for winter • Physiological Adaptations: the ability of the organism to perform special functions • Ex: venom production, temperature regulation, growth and development.
Darwin’s Four Premises • Overproduction – each species produces more offspring than will survive to maturity • Variation – individuals in a population have slightly different traits • Selection – individuals compete and the environment selects those with traits that help survival and reproduction • Adaptation of a Population/Successful Reproduction – beneficial traits become more common in the next generation
Coevolution • Coevolution: When two species evolve in response to long-term interactions with each other • - The Hawaiian honeycreeper has a long, curved beak to reach nectar at the base of a flower • - The flower has structures that ensure the bird gets some pollen on its head • - When the bird moves the next flower, some of the pollen will be transferred, helping the flower reproduce
Coevolution • - The honeycreeper’s adaptation is a long, curved beak. • - The plant has two adaptations: • - 1. the sweet nectar to attract the birds • - 2. the flower structure that forces pollen onto the bird’s head when it sips nectar
Man Selects • Artificial selection:selective breeding of organisms, by humans, for specific desirable characteristics. • - Dogs have been bred for certain characteristics • - Sporting, Hunting, Herding, Terriers, Working, etc. • - Fruits, grains, and vegetables are also produced by artificial selection. • - Humans save seeds from the largest, and sweetest fruits • - Farmers direct the evolution of crop plants to produce larger, sweeter fruit
Evolution of Resistance • Resistance: the ability of an organism to tolerate a chemical or disease-causing agent • - An organism may be resistant to a chemical when it contains a gene that allows it to break down a chemical into harmless substances • - Humans promote (encourage) the evolution of resistant populations by trying to control pests and bacteria with chemicals.
Evolution and Resistance • Pesticide and Corn: • -A pesticide is sprayed on corn to kill grasshoppers, may kill most of the grasshoppers, but some develop resistance • - The hoppers that survive could have a gene that protects them from the pesticide • - These surviving insects pass on this resistant gene to their offspring • - Each time the corn is sprayed, more resistant grasshoppers enter the population • - Eventually the entire population will be resistant, making the pesticide useless
Antibiotic Resistance Video • http://sixtyminutes.ninemsn.com.au/article.aspx?id=8615278 • http://abcnews.go.com/GMA/video/aimee-copeland-gma-interview-battle-flesh-eating-disease-17216238
Evidence for Evolution • Homologous Structures • Vestigial Structures • Biochemical Evidence
Homologous structures: Similar Structures in Different species suggest a common ancestor
Homologous Structures -Show descent with modification -Traits that are similar between different species have been inherited from a common ancestor
Vestigial Structures • traces of structures from ancestral species that serve no current useful function ex. Pelvic Bones in whales, appendix in Humans
Comparing DNA • Biochemical Evidence: Shows DNA similarities and relatedness • The more DNA species have in common, the more closely related they are • Ex. Human and Chimp are about 98% same DNA
Convergent vs. Divergent • Convergent evolution • Different species produce similar adaptations • Divergent evolution • Similar species produce different adaptations