Evolution

Some Questions that can be answered by EVOLUTION Why do so many different animals have the same structure…..the arm bones in humans are the same bones as a flipper in a whale?

Homologous Structures Similar structures, used for different purposes, that arose from a common ancestor This is also called Divergent Evolution ( diverge means to go in different directions )

Analogous Structures Different structures, used for similar purposes, that arose from a different ancestor: This is also called Convergent Evolution ( converge means to come together )

Divergent or Convergent Evolution? Use your knowledge to determine if these organisms demonstrate divergent or convergent evolution? Be able to explain you thoughts!

Convergent Evolution

Divergent Evolution Click on the image to view a short video

Some Questions that can be answered by EVOLUTION Why do organisms have structures they no longer use, like ….. ….the appendix in a human? ….non-functioning (non-flying) wings in a penguin? …. Pelvis in a whale?

Vestigial Structures

Vestigial Structures legs on a snake

Some Questions that can be answered by EVOLUTION Why are there bones and fossil evidence of creatures that no longer exist? What happened to those creatures? Draco rex

Complete the “How do Fossils Show Change” Activity

Formation & Change of Continents

Some Questions that can be answered by EVOLUTION Why is the sequence of DNA very similar in some groups of organisms but not in others?

Primate Ancestors Humans and Chimpanzees share 95% of DNA Humans and bananas share 50% of DNA

Some Questions that can be answered by EVOLUTION Why do the embryos of animals look very similar at an early age? Can you guess what kind of organism each embryo is?

Reproduction Asexual Offspring have same genes as PARENT Little or no variation from generation to generation Sexual Offspring receive some genes from BOTH parents Mixed genetic code New combinations may lead to new traits---- good or bad

Darwin’s Theory of Evolution by Natural Selection (1) Variation exists among individuals in a species. (3) Some competition would lead to the death of some individuals while others would survive. (The process he describes is known as NATURAL SELECTION)

Darwin’s Theory of Evolution by Natural Selection (2) Individuals of species will compete for resources (food & space) (4) Individuals that had advantageous variations are more likely to survive and reproduce. (These are called ADAPTATIONS)

Genetic Drift Not all individuals will be able to contribute their genes to the next generation. The random changes in allele frequency that occur in all populations  the smaller the population the BIGGER the effect!!

Genetic Drift animation

Darwin’s Finches Darwin noted that all the finches on the Galapagos islands looked about the same except for the shape of their beak.

Darwin’s Finches His observations lead to the conclusion that all the finches were descendants of the same original population.

Darwin’s Finches The shape of the beaks were adaptations for eating a particular type of food (Ex. long beaks were used for eating insects, short for seeds)

Natural Selection. Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic (heritable) basis of any phenotype that gives a reproductive advantage will become more common in a population (see allele frequency).phenotypegeneticallele frequency View video of Darwin

Natural Selection. Natural selection is the gradual, non-random, process by which biological traits become either more or less common in a population as a function of differential reproduction. non-random biological traits population It is a key mechanism of evolution. evolution Notice: less white mice Notice: less green bugs

The Founder Effect

Polydactyl: extra fingers or toes

Mutations Not beneficial mutations

Mutations Not beneficial mutations

Mutations Beneficial mutations

Mutations Sickle cell anemia Beneficial mutations

Carriers are resistant to malaria Full sickle cell disease can kill you… so can malaria

What mutations would you choose? Why?

Evolution What do you know about whales? Mammals Breath air. Evolutionary characteristics from the video: Click image to play video

Evolution

Lucy is the first recognized humanoid What differences do you notice? What things are the same?

Organisms belonging to the same species… A.Live in the same place and have similar characteristics B.Live in the same place and are active during the day C.Can mate with one another to produce fertile offspring D.Can mate with one another but cannot produce fertile offspring.

Co-Evolution Toxic newts Ancient Farmers of the Amazon Ancient Farmers of the Amazon So, what is Coevolution?

Mimicry Guess which one is poisonous? Red on yellow, poison fellow; red on black, safe from attack.

Mimicry Guess which one is poisonous.

Camouflage Can you find the animals in these pictures? Camouflage can be a form of mimicry. What are these frogs trying to mimic?

Camouflage Can you find the animals in these pictures?

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Camouflage What are the 2 most important reasons that organisms have genetically evolved to become camouflaged with their environments? 1.To hide from predators 2.To hide from prey (in order to sneak up on them)

Sexual Selection

Sexual Selection click image below for video

Sexual Selection

Artificial Selection

Some “Weird” Animals

More “Weird” Animals