Transcript STAR info
Stuff you need to know… TERMS TO KNOW!! EVOLUTION: the process by which modern organisms have descended from ancient organisms. (“CHANGE OVER TIME”) Central Idea: organisms alive today have been produced by a long process of change over time. FITNESS: refers to traits and behaviors of organisms that enable them to survive and reproduce COMMON DESCENT: species share common ancestors ADAPTATION: any inherited characteristic that enhances an organism’s ability to survive and reproduce ~based on variations randomly inherited Charles Darwin’s Explanation on Evolution (six major ideas of Darwin) Overproduction occurs in nature Not all organisms can survive Variation occurs in all populations Variations are inherited Organisms with favorable variations survive and reproduce Populations as a whole become FIT = evolved! Insecticide applied Genetic Drift Changes in the gene pool of a small population due to chance Examples: -Bottleneck Effect: results from drastic decrease in population size -Founder Effect: few individuals in a population colonize a new habitat Bottleneck Effect Speciation The origin of new species (the appearance of new species is the source of biological diversity) • Reproductive Isolation: barriers that prevent members of two species from producing viable, fertile hybrids • Geographic Isolation: Gene flow between gene pools is interrupted when a population is divided into two geographically isolated subpopulations – Ex: the water level in a lake decreases – Ex: a river splits a population into two Ecology 1) Life is ORGANIZED on many structural levels: Atoms Biological Molecules Subcellular organelles Cells Tissues Organs Organ Systems Complex Organism Levels beyond the individual organism: Population Community Ecosystem Biomes Biosphere Biodiversity • Stability in an ecosystem is a balance between competing effects. As a basis for understanding this concept: – Students know biodiversity is the sum total of different kinds of organisms and is affected by alterations of habitats. • Students know how fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration, and death. • Change in pop size = [B + I] – [D + E] Review • Autotrophs—capture energy from sunlight or chemicals and use that energy to produce food – AKA producers • Photosynthesis – Plants • Chemosynthesis – Bacteria • Heterotrophs (Consumers) – – – – Herbivores Carnivores Omnivores Detritivores • Feed on plant and animal remains – Mites, earthworms, snails – Decomposers • Break down organic matter – Bacteria and fungi Flow of Energy Energy flows through an ecosystem (a section of the biosphere) from the sun, to producers, to consumers IN ONE DIRECTION!!! Food Chains • Food Chain— transfer of energy by eating and being eaten Food Webs • Food Web— describes complex relationships of organisms in an ecosystem – A food web links together all the food chains in an ecosystem Energy Pyramid Tertiary Consumers Producers • Shows the relative amounts of energy contained within each trophic level in a food chain or food web • Only part of the energy that is stored in one trophic level is passed on…(10%) • each step of an organism eating another organism is called a trophic level (trophe means food in Greek) • Approximately 10% of the energy at one trophic level can be used by animals at the next trophic level – ex: 10% of the plant's energy is stored in the tissues of herbivores (plant eating animals) & 10% of the energy is herbivores is stored in the tissues of carnivores (animal's that eat other animals) • More energy efficient to eat producers • Although energy moves in a oneway direction through an ecosystem, nutrients are recycled