Chapter 7 Changes Over Time   California Standard and Learning Objectives S 7.3 Biological evolution accounts for the diversity of species developed through gradual processes over many generations. As a basis for understanding this concepts: Students know both genetic variation and environmental factors are causes of evolution and diversity of organisms. Students know the reasoning used by Charles Darwin in reaching his conclusion that natural selection is the mechanism of evolution. Students know hos independent lines of evidence from geology, fossils, and comparative anatomy provide the bases for the theory of evolution. Students know how to construct a simple branching diagram to classify living groups of organisms by shared derived characteristics and how to expand the diagram to include fossil organisms. Students know that extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient for its survival. S 7.4 Evidence from rocks allows us to understand the evolution of life on Earth. As a basis for understanding this concept: Students know fossils provide evidence of how life and environmental conditions have changed.

The gradual change in species over time is called evolution. (page 228)

Like environmental factors, genetic variation contributes to evolution. Darwin could not explain what caused variations or how they were passed on. Scientists later learned, variations can result from mutation and the shuffling of alleles during meiosis. Genes are passed from parent to their offspring Because of this, only traits that are inherited, or controlled by genes, can be acted upon by natural selection. (page 213) Genes in Evolution

A branching tree diagram shows probable evolutionary relationships among organism. (page 255)

In natural selection, individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species. (page 229) Darwin proposed that, over a long time, natural selection can lead to change. Helpful variations may gradually accumulate in a species, while unfavorable ones may disappear. Natural Selection

Naming System of Linnaeus Genus and Species The naming system Linnaeus used is called binomial nomenclature. Binomial means “two names.” The first word (genus name) in an organism’s scientific name is its genus. Genus is a classification grouping that contains similar, closely related organisms. The second word (species name) in a scientific name often describes a distinctive feature of an organism, such as where it lives or its appearance. (page 250) Species is a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce. (page 225 & 709) Naming System of Linnaeus Genus and Species

Classification and Taxonomy The process of grouping things based on their similarities is called classification. (page 249) Biologists use classification to organize living things into groups so that the organisms are easier to study. The scientific study of how living things are classified is called taxonomy. (page 249) Classification and Taxonomy

Eight Classification Levels A domain is the highest level of organization. Within a domain, there are kingdoms. Within a kingdom, there are phyla. (Phylum-singular) Within a phyla are classes. Within classes are orders. Within orders are families. Each family contains one of more genera. Each genus contains one or more species. (page 251) Eight Classification Levels

Levels of classification The more classification levels that two organisms share, the more characteristics they have in common. (page 251) Levels of classification

Genetic variations is a difference between individuals of the same species. (page 229)

Factors that contribute to the differences in species Genetics (genotype) contribute to the differences in species. Environment contributes to the differences in species. Factors that contribute to the differences in species

Adaptation is a trait that helps and organism survive and reproduce in its environment. (page 227)

Overproduction occurs in many species Overproduction occurs in many species. The reason is because not all the offspring will survive. Example: Turtles lay many eggs. When the baby turtle hatches it must travel from the egg’s nest to the water. Some will get eaten by their prey, other will simply not make it to the water and die. Overproduction

A fossil is a preserved remains or traces of an organism that lived in the past. (page 225) Majority of fossil are buried in sediment (dirt). A fossil can be a mold, cast, or petrified. (page 236) Picture of a mold of an animal in sedimentary rock: A mold is an empty space formed when an organism is buried in sediment and dissolves. FOSSIL

Members of the domain bacteria. Prokaryotes are organisms whose cells lack a nucleus. (page 253) Prokaryotes

A scientific theory is a well tested concept that explains a wide range of observation. (page 228) Scienctific Theory