REVIEW FOR THE BIOLOGY REGENTS EXAM (Part II)

1. REVIEW FOR THE BIOLOGY REGENTS EXAM(Part II)

2. GENETICS UNIT V • Humans have 46 chromosomes • Humans have 23 homologous pairs of chromosomes • Chromosome pairs carry alleles for the same trait. We all have two alleles for each gene – one from each parent, 1 on each homologous pair

3. Sex chromosomes: In humans, females are XX and males are XY • The Y chromosome is much smaller than the X, so males carry only a single gene for some traits. This makes the males more likely to have some traits (like color blindness). • These are called sex-linked traits

4. Gene expression While genes determine our traits, the environment can affect the expression of genes

5. Each chromosome has hundreds and thousands of genes • Each gene holds the code for a particular protein REMEMBER: • Genes carry the code to make protein, but genes (DNA) are made of nucleic acids

6. DNA DNA is made of 4 bases: A T C G The three letter codon represents a specific amino acid – these amino acids are assembled into proteins Base pairs: in DNA: A-T and C-G in RNA: A-U and C-G

8. MUTATIONS Changes to the DNA are called mutations. They can only be passed on if they are in the sex (reproductive) cells (egg or sperm) Common mutagenic agents include • Radiation • Chemicals • Viruses Mutations may cause a change in the structure of the protein coded for by a gene. This will have an effect on the way the protein works (if it works at all).

9. Differentiation All cells in the body have the same genes (DNA). Only some genes are turned on. We are not sure yet why this happens

10. Genetic Technology • Selective breeding: produces plants and animals with desired traits (disease resistant, larger fruit, leaner meat, more milk, specific colors) • Genetic engineering or gene splicing: inserts the genes of one organism into the genes of another. Restriction enzymes are used to cut the DNA segments. • Bacteria are often used because they have no nucleus protecting their DNA and they reproduce very quickly.

11. Bacteria Making Human Insulin

12. Newer Technologies Karyotyping

13. Newer Technologies Gel Electrophoresis

14. EVOLUTION UNIT VI

15. EVOLUTION Modern species evolved from earlier species and share a common ancestor

16. Charles Darwin Charles Darwin proposed that natural selection is the mechanism that causes change. The basic steps in natural selection are: • Overproduction of offspring. Offspring have variation. • Competition for limited resources. Variation affects the outcome of competition. • Survival and passing on genes or death and no passing on of genes • Variations that are beneficial are passed on and become more common. Variations that are harmful become less common because they are not passed on.

17. “Survival of the Fittest” Better adapted organisms are more likely to survive and pass their genes on. Less adapted organisms usually die and do not pass their genes on. Better adapted (more fit) organisms are not always stronger, they are just better adapted to the environment

18. Species that cannot adapt to their environment become extinct. Animals die – species become extinct Species do not evolve because they need to, they just have variations that are favorable, and those variations continue on (evolve). Variations exist as a result of sexual reproduction and mutations. Species with more variations are better able to survive environmental change than those with little diversity.

19. EVOLUTIONARY CHANGE PUNCTUATED EQUILIBRIUM: evolution occurred in quick bursts GRADUALISM: evolutionary change occurs slowly

20. Creation of a new species usually requires geographic isolation. Geographic isolation eventually results in reproductive isolation. Evidence in support of evolution comes from the fields of: • Geology (fossils and radioactive dating) • Genetics • Biochemistry • Anatomy (homologous and analogous structures) • Embryology

21. Deeper fossils are typically older than those above them.

22. Homologous structures:similar on the inside, different on the outside, modified for different functions

23. EVOLUTIONARY TREESshow the relationship between living and extinct species

24. CLASSIFICATION KINGDOMS are large groups of related organisms (bacteria, protists, animals, plants) SPECIES are able to successfully reproduce amongst its members Branching tree diagrams show evolutionary relationships

25. ECOLOGYUNIT VII Understand how organisms interact with their environment FOOD CHAIN FOOD WEB

26. ECOLOGY Understand how organisms interact with their environment THE NITROGEN CYCLE

27. ECOLOGY Understand how organisms interact with their environment THE CARBON CYCLE

28. ECOLOGY Understand how organisms interact with their environment THE WATER CYCLE

29. ENERGY Energy is needed to keep an ecosystem going. Energy comes from the sun and is made usable by producers (plants/autotrophes) Energy is passed on to other organisms in the form of food

30. ENERGY Since all organisms must use energy for their own needs, most energy is lost before it can be passed to the next step in the food chain. As a result, organisms high on the food chain have less energy available to them and must have smaller populations.

31. ENVIRONMENTAL FACTORS Environmental factors determine which organisms can live in an ecosystem and how large the populations can get. • Air • Water • Temperature • pH • Food • Predators

32. Carrying Capacity The maximum size of a population is called the carrying capacity

33. ECOSYSTEM NICHES There many roles in an ecosystem (niche), but competition between species usually results in only one species occupying a niche at any one time. Often organisms with similar needs will divide resources to reduce competition. Example: Birds eat insects during the day and bats eat insects at night.

34. ECOLOGICAL SUCCESSION

35. Ecology Vocabulary • Producer:an organism, usually a plant, that can produce its own food • Consumer:an organism, usually an animal, that feeds on plants or other animals • Omnivore:an animal whose normal diet includes both plants and animals • Herbivore: an animal that feeds chiefly on plants • Carnivore:an animal that feeds chiefly on meat • Predator: an organism that lives by preying on other organisms • Parasite: an organism that grows, feeds, and is sheltered on or in a different organism while contributing nothing to the survival of its host • Habitat: the natural home of an animal or plant

36. Ecology Vocabulary • Niche:the position or function of an organism in a community of plants and animals • Population: all the organisms that constitute a specific group or occur in a specified habitat • Community: a group of plants and animals living and interacting with one another in a specific region under relatively similar environmental conditions • Ecosystem: a system formed by the interaction of a community of organisms with their physical environment • Biosphere: the part of the earth's crust, waters, and atmosphere that supports life • Pollution: the introduction of harmful substances or products into the environment • Renewable resource: any natural resource that can replenish itself naturally over time, as wood or solar energy

37. HUMAN ECOLOGY Human action often has negative consequences for the ecosystem and humans, too! • Development • Industrialization • Over harvesting • Over hunting • Introduction of foreign species • Soil erosion

38. Introduction of foreign species Common foreign species in New York State: • Plants • Purple Loosestrife • Garlic Mustard • Animals • Round goby • Zebra Mussel

39. The negative effects human’s have had on the environment are mostly attributed to the increasing human population causing • Acid rain : the burning of fossil fuels, such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain. • Loss of habitat: as more and more people move to the cities, urban sprawl replaces natural habitats. The habitats that remain are fragmented and depleted. • Loss of diversity: loss of habitats lead to loss of diversity • Loss of ozone: the over use of chloroflourocarbon (CFC) compoundshas led to the destruction of the layer over the earth that protects us from harmful UV rays (this has led to an increase in skin cancers)

40. The negative effects human’s have had on the environment are mostly attributed to the increasing human population causing • Global warming:Is the increase in the average temperature of the Earth's near-surface air and oceans • Introduced species:when natural species are threatened by the invasion of exotic plants and animals • Industrialization:rapid industrial growth and vehicle exhausts has made water pollution, air pollution, and hazardous wastes pressing environmental problems in many areas of the developing world

41. Actions being taken by humans to reduce or repair damage to the environment • Recycling wastes • Conservation of resources • Using renewable resources (solar, wind, water) • Protection of habitats • Use of biological controls instead of pesticides and herbicides • Farming native plants (favorable to the environment) • Planting trees to replace those cut down • Rotating crops or planting cover crops to reduce erosion • Passing laws to control pollution, land management, hunting, and fishing

42. BIODIVERSITY • Refers to the variety of life on earth • As habitats and are lost and species become extinct, biodiversity is reduced • Ecosystems with low diversity are less stable than ecosystems with more diversity • Ecosystems with low diversity take longer to recover from environmental changes • We use organisms for many things such as food and medicine; by reducing biodiversity we are losing potentially valuable resources