Presentation on theme: "16.1 Darwin’s Voyage of Discovery"— Presentation transcript:
1 16.1 Darwin’s Voyage of Discovery Lesson Overview16.1 Darwin’s Voyage of Discovery
2 Darwin’s Epic JourneyEvolution: process of change over timeDarwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.Darwin published his first complete work on evolution: On the Origin of SpeciesHe sailed on the HMS Beagle’s for five-years , mapping the coastline of South America.
3 Darwin observed 3 patterns of Biodiversity Species vary globally – different yet ecologically similar animals are found in different yet similar environments.2. Species vary locally – different yet related species occupy different habitats in one area.3. Species vary over time – fossils of extinct species are similar to current species.
4 Evolution The Earth is old and the process of change exists today. Traits acquired during an organism’s lifetime are NOT passed to it’s offspring!Most organisms don’t survive to reproduce!Examples: sea turtles, insects, etc.
5 Common descent!Common descent – all species (living and extinct) descended from a common ancestor!Over many generations, adaptations caused a successful species to evolve into a new species!The fossil record provides evidence for this descent with modification!
6 Evidence of descent from common ancestors: 1. Geographic distribution of species2. Fossils3. Anatomy (homologous structures)4. Physiology (analogous structures)5. Embryology6. Universal genetic code
7 Artificial selectionNature provides variation in organisms’ traits, buthumans choose to breed those organismsthat have the most useful traits.n Example: humans breed cows that produce themost milk.N Example: humans breed trees that create themost fruit.
8 Natural SelectionNatural selection is the process by which organisms with variations most suited to their local environment survive and reproduce.By surviving, these attributes can be passed onto their children, causing an increase of these traits in the species population, thus causing a gradual change in the characteristics of the population.Individuals whose characteristics are not well-suited totheir environment die or leave few offspring.Because natural selection favors a certain trait overothers, more individuals in the population carry thegenes for that trait.survival of the fittest.
9 Species Vary Locally- Finches Adapted from one original species. Due to different food availability.
11 The scarlet king snake exhibits mimicry—an adaptation in which an organism copies, or mimics, a more dangerous organism. Although the scarlet king snake is harmless, it looks like the poisonous eastern coral snake, so predators avoid it, too.A scorpionfish’s coloring is an example of camouflage—an adaptation that allows an organism to blend into its background and avoid predation.
12 Fitness describes how well an organism can survive and reproduce in its environment. Individuals with adaptations that are well-suited to their environment can survive and reproduce and are said to have high fitness.
14 PHYSIOLOGYAnalogous structures Body parts that share a common function, but not structure.Examples: a bat’s wing and a moth’s wing--both are wings and both are used for flight, but a bat has bones and a moth does not.Vestigial Structures- body structures that have reduced or no body functionAs species adapt to environments the change in form and behavior and continue to inherit these structures as part of the body even though theyhave no function.Examples: A human’s appendix, a whale’s pelvis!
15 ANATOMYHomologous structures – similar in structure but differ in function!parts of different organisms (that are often quite dissimilar) that developed from the same ancestral body parts!Forelimbs of whales, bats, crocodiles, and chickens have similar anatomy but are modified for different functions – common Ancestry!