PSSA Science Review Organisms and the Environment Organisms and the Environment 1. Natural Selection 2. Heredity 3. Ecological Relationships and Systems 4. Change and the Environment 5. Humans and the Environment 1. Natural Selection Adaptation Structural, physiological, behavioral Passed on to offspring, increasing their chances of survival Result of random mutation of genes Natural Selection 1
Survival of Organisms Reproduction Inherited traits Random Mutation Variations Adaptations Mismatch with environment Survival Death; no offspring Evolution Gradual process Happens to a species Extinction Variations Sample Questions 1. A certain plant species has evolved to contain a bad-tasting chemical. Which of the following is the most likely outcome of this adaptation? A. Animals are less likely to eat the plant B. The plant will be able to live in many different environments. C. The chemical is used to aid in photosynthesis. D. Animals are more likely to eat the plant. 2
Charles Darwin observed different finch species on the Galapagos Islands. The different finches had evolved to have breaks of varying size and shape that allowed them to eat certain kinds of food. Choose the answer below that best completes the table from top to bottom with the correct order of the beak adaptation for each finch, based on the type of food it eats. A. B. C. Type of Finch A. Tree Finch B. Vegetarian Finch C. Cactus Finch Type of Beak Food Source Insects A. Strong, stout beak; Small, short beak; Long, thin beak B. Small, short beak; Long, thin beak; Strong, stout beak C. Small, short beak; Strong, stout beak; Long, thin beak D. Long, thin beak, Small, short beak; Strong, stout beak Fruits and hard seeds Cactus fruits and insects inside cactus flowers 2. Heredity Genetics Heredity Mendel s Experiments & Observations Work with pea plants formed the basis of genetics Studied seven characteristics of pea plants P1 Generation: parental plants F1 Generation: offspring of the P1 generation Dominant trait Recessive trait 3
Sample Questions 1. Which of these best describes genetics? A. The transmission of qualities from parents to offspring. B. Comparing dominant and recessive traits. C. The field of biology that investigates how characteristics are transmitted from parents to offspring. D. The growing of pea plants. 2. A guinea pig with black coat color is crossed with a guinea pig with brown coat color. All their offspring have black coat color. Which of these conclusions can you draw from this observation? A. Brown coat color is the dominant trait. B. Black coat color is the dominant trait. C. Black coat color is the recessive trait. D. Neither coat color is a dominant trait. 3. Which of these best describes how you can tell whether a trait is dominant or recessive? A. Compare the traits of the P1 and F1 generations. B. Examine only the traits of the F1 generation produced in the cross. C. Count the number of organisms used in the cross. D. Determine the age of the organisms used in the cross. 3. Ecological Relationships and Systems Ecosystem Abiotic Factors Biotic Factors 4
Interactions Competition Predators Prey Symbiosis Mutualism Commensalism Parasitism (parasite, host) Biomes Biome Terrestrial Biomes Temperate deciduous forest Coniferous forest Tropical forest Grassland Desert Tundra Biomes Marine Biome Intertidal zone Neritic zone Oceanic zone Benthic zone Freshwater Biome Wetlands 5
Sample Questions 1. The cattle egret perches atop the buffalo s back where it is carried from one location to another and eats insects flushed from the grass as the buffalo moves. The buffalo is not benefited or harmed. What is this an example of? A. mutualism B. commensalism C. parasitism D. predation 2. An example of a biotic factor is A. temperature B. drinking water C. fungi D. oxygen 3. Which of these is an example of a freshwater biome? A. tundra B. deciduous forest C. ocean D. marsh 4. Change and the Environment Population Size Density Factors that affect population 6
Populations need an equilibrium of number of births and death Limiting Factor Examples: Carrying Capacity Populations will grow until the carrying capacity is reached. Succession Primary succession Secondary succession Sample Questions 1. Which of these best describes a stable population? A. more births than deaths B. more deaths than births C. number of births equals number of deaths D. no births at all 2. Which statement best describes how limiting factors affect the organisms in an ecosystem? A. They destroy resources organisms need to survive. B. They provide what an organism needs to survive. C. They keep a population from getting too large. D. They have no effect on the organisms in an ecosystem. 7
3. Which term represents the maximum number of individuals an ecosystem can support? A. population density B. carrying capacity C. succession D. climax community 4. Which event will most likely causes secondary succession to occur? A. fire B. volcano erupting C. predator moving in D. seasons changing 5. Humans and the Environment How do humans change the environment? Resource Use Natural Resource Renewable Resource Nonrenewable Resource Fossil Fuels 8
Conservation Sustainable Development Desertification Deforestation Overfishing Pollution Pollutants Air Pollution Water Pollution Sample Questions 1. Which of the following is not an example of sustainable development? A. plowing the land to prevent erosion B. replanting forests with a variety of trees C. conserving water D. desertification 2. Which of the following is a nonrenewable resource? A. natural gas B. marsh reeds C. game animals D. a wheat crop 9
3. What is the best description of the process of sustainable development? A. using renewable resources at a rate faster than they can be restored B. using resources without destroying or depleting them while providing for human needs C. using nonrenewable resources to satisfy human needs while ignoring needs of other living organisms D. using nonrenewable resources without care for their consumption 4. An example of a renewable resource is A. water B. coal C. natural gas D. minerals 10