Evolution Day 1 Journal Prompt: Tell me what you know about evolution, use the information you have heard in the past to give me a brief summary of what you think evolution is.

Evolution

Evolution Change in a population of organisms over time.

Cladograms – a diagram of evolutionary relationships

Cladogram Introduction Mr. Anderson’s introduction of Cladograms https://www.youtube.com/watch?v=ouZ9zEkxGWg

Make a cladogram using what? Derived Characteristics: unique characteristics of a particular group of organisms AKA: found in one group of organisms but are not found in the older members of the lineage

Cladograms – a diagram of evolutionary relationships Cladogram starts as a single branch that then splits several times into organisms who evolved from each other If you follow a branch it sometimes splits at nodes into two or more branches to show new species Used to tell how closely related organisms are

Cladograms Each node represents a new trait that has evolved and the common ancestor that evolved that trait. As you follow an organisms path in the cladogram from the beginning to the end, you can find out the organisms adaptations through time. Each node it goes through is a trait that it evolved, in that order.

Cladograms 100 million years go by …

Cladograms: Complete the table below! Use the information in the table to construct a cladogram of these animals. Organism Derived characteristics Backbone Legs Hair Earthworm Trout Lizard Human

Derived characteristics Making a Cladogram Which organism is least like the others? Earthworm Organism Derived characteristics Backbone Legs Hair Earthworm Trout Lizard Human + + + + + +

Derived characteristics Making a Cladogram At the bottom help me to do the following: Develop a cladogram showing the evolutionary relationships between all 4 animals. Organism Derived characteristics Backbone Legs Hair Earthworm Trout Lizard Human + + + + + +

Making a Cladogram Earthworm Trout Lizard Human Hair Legs Backbone

Which animal is species X most closely related to on the cladogram? Earthworm Trout Lizard Human X Backbone Legs Hair

Cladogram Activity Lets build a cladogram Using the pictures of the organisms create a cladogram and answer the questions that follow the lab

Evolution Day 2 Journal: Explain what we use cladograms for. How do we make them?

Video Introduction What is evolution – Stated Clearly https://www.youtube.com/watch?v=GhHOjC4oxh8

Evolution Change in a population of organisms over time.

WHAT IS EVOLUTION? To evolve: to change A theory stating that all life has changed from simpler life to more complex life Occurs over LONG periods of time Evolution often supports that organisms have evolved from a common ancestor

But wait…… What did life start as to evolve?? Miller and Urey experiment: tried to replicate the origins of life on earth; mixed gases together to form complex molecules Successful but experiment had several flaws so debate still ongoing as to the original life on earth

Theories of Evolution Jean-Baptiste Lamarck – 1809 published his theory of evolution Mechanism of Evolution = Inheritance of Acquired Characteristics

The theory of evolution His explanations were: Tendency towards perfection Use and disuse= if you use it, you keep it; if you don’t use it, you lose it Inheritance of acquired traits= traits are passed down through generations Problem with his theory…he didn’t understand HOW

Theories of Evolution Charles Darwin – 1859 published his theory of evolution in the major work, On the Origin of Species Mechanism of Evolution = Natural Selection

Charles Darwin Darwin was a naturalist that traveled on the HMS Beagle to the Galapagos Islands in the Pacific Ocean. He observed many different plants and animals to include giant tortoises and finches. He noticed that the birds had different shaped beaks and he hypothesized that this had something to do with their diet.

Comparison of Lamarck’s and Darwin’s Ideas on Evolution 1.Short necked herbivore lives in savanna 2 a)Grasses are available to the animals. Trees leaves are out of reach of most of them 2 b) Animals are adapted to their environment. Darwin 1. Same 2 a)Same 2 b) Same

Comparison of Lamarck’s and Darwin’s Ideas on Evolution Lamarck 3. The animals stretch their necks to reach the leaves on the trees. Continued stretching causes an elongation of necks. 4. The animals reproduce. The young have long necks. Darwin 3. Due to variation in the population there is a range of neck lengths. Some animals naturally have longer necks than others. 4. Those with longer necks can reach the tree leaves.

Comparison of Lamarck’s and Darwin’s Ideas on Evolution Lamarck 5. In the event of a shortage of grasses (drought), the animals are able to feed on leaves.  The long necked animals are the most fit! These are the animals that survive and reproduce. Darwin 5. In the event of a shortage of grasses (drought), the animals are able to feed on leaves.  The long necked animals are the most fit! These are the animals that survive and reproduce.

Comparison of Lamarck’s and Darwin’s Ideas on Evolution 6. Over the next generations, the longer necked animals will continue to stretch and elongate their necks. 7. Each generation will pass on their longneck to their young Darwin 6. Over the next generations, (due to mutations, new gene combinations, crossing over) there will again be variation in neck length 7. Those with the longest necks will be be most fit--with the greatest chance of survival.

evolution Artificial Selection- process by which we select the best organisms to mate and produce offspring; we are selecting for specific traits Ex. Breeding dogs, cats, livestock, etc Struggle for existence- there is regular competition for the resources (food, space, etc.) necessary for living which leads to the concept of… Survival of the fittest- only the organisms who have the traits that make them better suited for their environment will survive, reproduce and have offspring that survive.

Evolution Natural selection- a.k.a., survival of the fittest, “nature” (the environment) will “select” the organisms that will survive through the challenges they face day-to-day. Descent with modification- generations are modified from their ancestors due to natural selection

Theory of natural selection Variation exists within a population Variation is inherited Resources are limited More organisms are produced than will survive The organisms that are best suited for the for the environment will survive and produce offspring.

Types of Natural Selection Disruptive Stabilizing Directional

Variation and Natural Selection Most phenotypes (traits) are polygenic. A graph of these traits often shows a bell curve.

Stabilizing Selection If individuals near the center of the bell curve have higher fitness (= leave a greater amount of fertile offspring) then stabilizing selection occurs.

Directional Selection If individuals at one end of the bell curve have higher fitness then directional selection occurs. Example: long necks

Disruptive Selection If individuals at both ends of the curve have higher fitness than those in the middle then disruptive selection occurs.

Genetic Drift If a small population is isolated from others of the same species, it is possible that just be “chance” one allele may become more common in a population.

How do new species form? Example: Galapagos Finches A small group of a species of finch arrives on one of the Galapagos Islands These finches do not usually fly across open water—they may have gotten lost or were blown there by the wind.

Speciation continued! Over time these original finches may have ended up on other of the Galapagos Islands through some chance occurrence. USUALLY the finches do NOT fly from one island to another.

Speciation continued! The Galapagos Islands had different environments. Some had a low elevation and were dry with little plant material.

Speciation continued! Others had a higher elevation with greater rainfall and many plants.

Speciation continued! Directional selection occurs: One island may have seeds that are large and difficult to open. Birds with a larger, thicker beak will have the highest survival rate on this island

Speciation continued! Directional selection occurs: Another island may have seeds that are small and easy to open Birds with a small, thinner beak will have the highest survival rate on this island

Speciation continued! Reproductive Isolation: if the populations remain separate, and their gene pools continue to change, eventually they can no longer mate with each other—they are then TWO NEW SPECIES!!! On the Galapagos Islands this processes resulted in the evolution of 13 different finch species.

Darwin’s Finches

Support of Darwin’s Theories 1. Fossil record 2. Geographic distribution of living things 3. Homologous body structures 4. Vestigial Structures 5. Similarities in embryology 6. Biochemical similarities

1. FOSSIL EVIDENCE The fossil record shows that life HAS changed over time, Fossils: remains of organisms that lived in the past Ex. Imprints/bones/teeth/preserved insects Form in sedimentary rock and the weight of the subsequent layers turns the organisms into rock Indicate change (see what organism looked like then compared to now; see organisms that lived in past but no longer exist today

Older fossils will be deeper in sediment Layers are deposited over time on top of the older layer Fossils show that organisms have evolved from SIMPLER organisms (bacteria, invertebrates) in the lower layers to more COMPLEX organisms (vertebrates: fish…reptiles…mammals) in the upper layers EX: a magnolia (flowering plant)would be younger than a fern A squid (invert) would be older than a lizard (reptile)

EVIDENCE FROM FOSSILS How has the horse changed over time? How would studying the fossil evidence of the horse support the theory of evolution? The fossil evidence shows that the horse has changed over time in height, teeth structure, and bone structure

What would this fern fossil tell us about climate? This fossil was found in Antarctica. How could Antarctica have the type of climate suggested by this fossil evidence? Antarctica must have been a warmer climate; ferns are tropical plants If it had been closer to Equator; Pangaea

Dating Relative dating- age of the fossil is determined by comparing it to stratified rock around it. Absolute dating- provides a fairly precise date; uses radioactive elements, also known as carbon-14 dating Uses the half-life of the element- this is the amount of time it takes for half of the sample to decay

2. Geographic distribution Geographic distribution of living things- similar but unrelated species These 2 crocodiles were found on separate continents.

3. Homologous body structures Homologous body structures- these are structures that are built the same but may be used differently Suggests common ancestry Ex. The wing of a bird and the arm of a human

HOMOLOGOUS STRUCTURES EXAMPLES Leg of dog Arm of human Wing of bird Flipper of whale All have similar bone structure, but the function is different (leg-walking; arm-carrying; wing-flying; flipper- swimming)

4. VESTIGIAL STRUCTURES Structures present, but have no purpose Structures that are incomplete The presence of these structures indicates the structure once had a purpose (support for evolution) EX: femur/ pelvis in whales, appendix in humans

Vestigial Structures in Humans

5. EMBRYONIC similarities EMBRYO: early stage of development of living things Many organisms look similar very early in their development More stages similar… the more closely related they are Suggests common ancestry (note how similar these different organisms are in early stages)

6. BIOCHEMICAL EVIDENCE BIOCHEMICAL evidence is referring to similarities in DNA, proteins, amino acids, enzymes, etc. The more similar these compounds are in different organisms, the more closely related they are Suggests common ancestry BIOCHEMICAL SIMILARITIES OF ORGANISMS Comparison of Organisms % substitutions of amino acids in Cytochrome C Two orders of mammals 5-10 % Birds vs. mammals 8-12 % Amphibians vs. birds 14-18 % Fish vs. Land vertebrates 18-22 % Insects vs. vertebrates 27-34 % Algae vs. animals 57 %

Biochemical Evidence We are most similar/ most closely related to chimp least similar/ closely related to chicken Hedgehog is most similar to mouse… based on the closeness of the DNA similarities…3% difference

Station Two

Natural Selection How does natural selection result in a new species? Variation in a population comes from sexual reproduction and from different types within the species mating. Gene pool- all genes that are present in a population

Forming New Species What can lead to the formation of a new species? Behavioral isolation- 2 populations do not mate because of differences in courtship behavior, vocalizations, etc. Geographic isolation- 2 populations do not mate because they are separated by a physical barrier Immigration and emigration- individuals are introduced to a new location and are allowed to mate Migration- similar to immigration and emigration; just occurs seasonally and may not result in new mating partners

Patterns of evolution Divergent evolution (adaptive radiation)- a single species evolves into many through a variety of changes in the environment Supported by DNA and/or protein structures Ex. Monkey foot and human foot Convergent evolution- different organisms become more alike over time due to being in the same environment Supported by homologous structures Ex. Bird wing and bat wing Co-evolution- organisms need each other for survival therefore will evolve together Ex. Bumblebees and flowers