unit 8 organization of life, plants, and evolution

Unit 8 Organization of Life, Plants, and Evolution

What is Evolution? Darwins Theory of Evolution (Chapter 15) A. Charles Darwin In 1831 Charles Darwin took a trip to the Galapagos Islands as a naturalist aboard the HMS Beagle. This trip took 5 years, and allowed him to see and collect collections of animal species. What evidence led Darwin to develop the theory of natural selection and common descent to explain evolution? Similiarities between fossils, the relationships between finches and tortoises on the different islands.

B. Natural Selection Darwins Theory of Evolution is based on the mechanism of Natural selection. Artificial Selection is what happens when humans choose who breed and survive. Natural Selection is what happens when only the most fit survive and nature determines who will breed and survive. The Four principles of Natural Selection include:

1. Variation - Organisms in a population are different from one another 2. Heritability - Traits are passed from parent to offspring 3.Overproduction Populations produce more offspring than can survive, this creates competition for resources. 4.Reproductive Advantage Variations make some organisms of a species more likely to reproduce and have more offspring than others.

Evolution means to change over time. C. Evidence of Evolution Darwins theory states that evolution is a result of natural selection Evidence includes: 1. The Fossil Record allows scientists to study and compare traits. a. Derived traits newly evolved/different traits found in organisms b.Ancestral traits traits similar between ancestor and modern day organisms. c.Radioactive Isotopes- used to track the age of fossils

Comparative Anatomy Related structures between organisms. a. Homologous Structures - Similar structures inherited from a common ancestor Example animal forelimbs b.Vestigial Structures Structures that have reduced or lost function Examples snake pelvis, kiwi wings, human appendix c. Analogous Structures Similar structures inherited from unrelated species Species- not from common ancestors. Examples eagle/beetle wings

Divergent Evolution Ex:

Convergent Evolution

3. Comparative Embryology Similarities between vertebrate embryos. 4. Comparative Biochemistry Similar enzymes, amino acids, DNA, RNA, and other molecules 5.Geographic Distribution - Related organisms share geographical distribution D. Adaptation An adaptation is a trait that increases an organisms fitness Fitness the measure of an organisms ability to make reproductively viable offspring

Adaptations include: 1. camouflage - to blend with environments. camouflage 2.Mimicry - to resemble other species 3.Antimicrobial resistance to be immune to antibiotics

**Remember, and Allele is one of the two traits given by an offspring's parents. It is one letter in a genotype: Bb-B dominant allele and b-resesive allele

E. Mechanisms of Evolution In addition to natural selection other mechanisms affect evolution. These include: 1. The Hardy-Weinberg principle allele frequencies stay Constant, a population is in genetic equilibrium. Example- Screech owls come in two colors: Brown and Gray. Since the number of alleles that code for brown and gray are the same, there is an equal proportion of brown and gray screech owls in a population

Hardy-Weinberg Principle

2. Genetic Drift-change in allele populations due to chance (Random reception of alleles from Mom and Dad Example- A group of butterflies comes in two colors: blue and brown. The brown butterflies die out, leaving only blue butterflies to pass on their alleles to the next generation

Sulfur Butterflies

3. Founder Effect-a small population settles in an area and is separated from the larger populationFounder Effect Example: Galapagos Finches settled on different islands and developed different characteristics

4. Bottleneck-when populations decline to very small numbers and then rebound, several traits may disappear in the population Example- Northern Elephant Seals over a period of time many died out and when the population made a comeback, there was less genetic diversity

5. Gene Flow-When individuals from other areas migrate into a population, the genetic diversity of the population increases. Example-A Species of Bird that is blue colored, has an individual migrate in that is red colored.

6.Nonrandom Mating: Selecting a mate for particular traits that are found desirable. Links Closely with Sexual Selection: Example Peacock, Antlers on a deer, and Male Frigate Bird

7.Mutation-changes in a genetic code that occur randomly Example-Antibiotic resistance in bacteria

Types of selection: 1.Directional Selection- when there is pressure for resources, the population moves towards a certain trait to adapt: Ex: Giraffe Necks 2.Stabilizing Selection- eliminates the extremes of a population: Ex: Rabbits with long legs and short legs 3.Disruptive Selection- Eliminates the average selection for organisms in favor of the extremes. Ex: Acorn size

4.Sexual Selection-selection of organisms with sexually attractive traits: (Ex. Deer antlers) 5.Balanced selection (polymorphism)- genetic equilibrium has occurred: No evolution occurs.

Reproductive Isolation Prevents groups of organisms from Reproducing Speciation - Causes a population to diverge and split into two separate species. 1. Allopatric - a physical barrier-prevents species from mating Examples-Two species of squirrel separated by the grand canyon

2.Sympatric - no geographic barrier- individual species evolve from common ancestors in the same location Examples-Species of fruit flies have evolved to feed on different apples in the same regions:

Patterns of Evolution 1. Adaptive Radiation (also known as divergence) One species gives rise to many Example different finch species adapt to different habitats 2.Coevolution - a species has a close relationship with other species Example orchids/moths, sharks/remoras, etc. 3.Convergent Evolution - 2 unrelated species become similar Example placental and marsupial animals

Adaptive Radiation

Co-Evolution

Convergent Evolution

F. Sexual Reproduction vs. Asexual Reproduction- Sexual Reproduction gives an evolutionary advantage to organisms because it gives them diversity. Example: immune systems develop in response to new experiences with microbes and evolves with each experience.

Genetic Isolation is the prevention one species from mating with another: 1. Llama and Camel

2. Polar Bear and Brown Bear

3. Cheetah and Leopard

4. Fox Squirrel vs. Black Squirrel

Archaeopteryx

Terror Birds

Cuttlefish camouflage

Something to think about If it takes many years for species to evolve than is it individuals or populations that evolve? Populations: It takes an individual with certain adaptations and many generations for the adaptation to evolve in the population. In the end natural selection can be simply defined as: Bono is from an island that consists of 200 people, from what you learned, what are some assumptions that you can make about Bono and the rest of the people on his island compared to that of someone from New York City.

Classification of Living Things The study of life is Biology Draw the kingdom of science, and how each area of science is related.

Biology and the Animal Science The science of grouping organisms on the basis of their similarities is called Taxonomy Aristotle (350 BC) was the 1st to subdivide into two groups: Plants and Animals Aristotles system lasted 2000 years

Carleus Linnaeus developed a new system based on 7 groups: 1. Kingdom 2. Phylum 3. Class 4. Order 5. Family 6. Genus 7. Species

Most animals are now referred to by their Genus and Species This is called their Scientific Name and is a practice known as Binomial nomenclature Examples: Homo sapiens, Humans : Canus lupus: Domestic Dogs

Organisms also have a Common name, which can sometimes cause a great deal of confusion such as mountain lion: puma, cougar, panther, catamount or starfish silverfish, jelly fish (none of which are fish). Modern taxonomists now group according to chromosome structure, reproductive potential, biochemical similarities, embryology, and evolutionary relationships. Members of the same species that differ in some important way are called subspecies Linnaeus divided according to two kingdoms: Plant Kingdom (autotrophs) Animal Kingdom (heterotrophs)

Now we have 5 (actually 6) Kingdoms 1.Monera (simple organisms without nuclei bacteria) 2 domains Archaebacteria and Eubacteria 2.Protista (with nuclei many are unicellular) 3.Fungi (multicellular heterotrophs absorb food through cell wall mushrooms etc.) 4.Plantae nucleated, multicellular autotrophs chloroplasts 5.Animalia multicellular heterotrophs nuclei

The study of taxonomy is huge. Computers have helped a lot. Identifying Organisms The study of classifying according to evolution Systematics The study of evolutionary relationships and phylogenies Phylogenetics The results of studies in systematics are used to construct a Tree of Life

Evolution by Natural Selection What are some differences you have noticed in the size and shape of the dogs in your neighborhood? Do their differences make them better at some things, but not well-suited for others? What would happen if the world suddenly changed, so the only thing that dogs could eat was deer and there was absolutely no way for a dog to eat if it wasnt big or strong enough to catch deer? Most likely, smaller dogs would die off and the bigger ones would survive and reproduce. After a while, instead of a population of dogs of all sizes, most of the dogs in the population would be large dogs.

Living things that are well adapted to their environment survive and reproduce. Those that arent well adapted dont survive and reproduce. An adaptation is any characteristic that increases fitness, which is defined as the ability to survive and reproduce. What are some characteristics of animals or plants that affect their fitness?

If a mouses fur color is generally similar to its mothers color what color fur would be most common among the pups?

A more complete definition of fitness is the ability to survive and produce offspring who survive and reproduce. Below are descriptions of four male lions. According to this definition, fitness, which lion would biologists consider the fittest? Explain why.

Suppose that Tyrone had genes that he passed on to his cubs that helped his cubs to resist infection, so they were more likely to survive to adulthood. These genes would be more common in the next generation, since more of the cubs with these genes would survive to reproduce. A characteristic which is influenced by genes and passed from parents to offspring is said to be inherited. Over many generations, heritable adaptive characteristics become more common in a population. This process is called evolution by natural selection. Evolution by natural selection takes place over many, many generations.

Evolution by natural selection leads to adaptation within a population. The term evolution by selection does not refer to individuals changing, only to changes in the frequency of adaptive characteristics in the population as a whole. For example, none of the mice had a change in the color of their fur, but tan fur was more common for the pups than for the mother mice. In summary, a heritable characteristic that helps an animal or plant to have more offspring survive to reproduce will tend to become more common in a population as a result of evolution by natural selection.

Questions: 1.Explain why a characteristic which helps an animal to live longer will generally tend to be more common in the population as a result of evolution by natural selection. 2.Not all characteristics which contribute to longer life become more common in the population. Some characteristics contribute to long life, but no more offspring. For example, a female which is sterile and cannot have any offspring may live longer because she will not experience biological stresses of repeated pregnancies. Explain why a characteristic like this which contributes to a long life, but with few or no offspring, would not become more common as a result of evolution by natural selection.

#1 #2 Key out the following organisms:

#10 #11

#12 #13

#14 #15

#16 #17

#18 #19

#20 #21

Vascular Plants Three parts of a vascular plant 1.Waxy outer cuticle that retains water 2.Stomata that allow gas exchange 3.A Vascular System (Xylem and Phloem)

The Vascular System 1.Xylem (carries water) 2.Phloem (organic materials food) This allows these plants to live successfully on land farther away from direct sources of water. All produce seeds

Seed Plants: Gymnosperms (naked seeds) These plants have needle-like leaves Cones are used to protect the seeds Most of these plants do not lose leaves Examples include spruce, fir, redwoods

Angiosperms Angiosperms are the most successful of all plants They have ovules that are totally enclosed They have colorful flowers that contain both male and female reproductive parts

Monocots: plants with 1 cotyledon: 1 Baby leaf Dicots: Plants with 2 cotyledons: 2 Baby leaves

Monocots vs Dicots

Flowers and Fruit All angiosperms produces reproductive structures called Flowers: Flowers contain both male and female parts. Once Egg and Sperm are fertilized, the flower falls off and the structures develop into fruits. This protects and disperses seeds.

Kinds of plant Tissue Epidermis outermost protective covering of the plant. Secretes a waxy layer of cutin. Vascular Tissue Plumbing system of xylem (water transport) and phloem (food transport) Ground Tissue unspecialized tissue that serves as protection and storage of food for the plants

Roots Anchor the plant, absorb minerals from the soil and store food produced in leaves.

Stems: Woody Stems: transport food water and minerals between roots and leaves and support the plant Buds a protective covering of the sensitive growing leaves so plant tips wont dry out

Leaves Blade: broad part of leaf, contains photosynthetic cells Petiole: leaf stalk, supports the blade Simple leaf: single un-divided blade Compound Leaf: divided into several parts

Structure of the Leaf Epidermis: single layer of cells for photosynthesis with waxy layer of cutin. Cutin: wax that helps slow evaporation Stomata with Guard cells: opening allows gas exchange with special cells that open and close stomata Mesophyll middle portion of the leaf Leaves and Water Loss Transpiration process of losing water

Stomata and Guard Cells (371) GAS EXCHANGEGAS EXCHANGE

L e af St r u ct u re Gas Exchange occurs here (CO 2 in O 2 out) (364)

Reproduction

Pollination The process in which flowers sexually reproduce Fertilization The union of an egg and a sperm of a plant Fruits and Seeds when the ovary of the plant swells and ripens to protect the seed, it is a fruit

Asexual Reproduction has the same genes as the parent plant Natural Propagation producing new individuals from roots or stems 1.Runners: also called stolons, low growing stems above the soil to make a new plant: strawberries 2.Rhizomes: long growing stems that grow below the surface to make a new plant: Potatoes and Yams 3.Bulbs: short stems surrounded by layers, self reproducing: Onions Artificial Propagation when humans reproduce vegetables artificially 1.Cuttings: cut a piece of stem and put it in water, and then, replant it. Lilac bushes 2.Grafting: cutting the stem of one plant and attaching to another: Grapes

How can you tell the age of a fossil? Radioactive isotopes- Some Elements decay over time. Carbon-14 Decays at a rate of losing part of its nucleus every 5,730 years. When checking the rate of decay, Scientists can figure out how old fossils are. Scientists not only take samples from the bones, but from the rock that was found around the bones.

Speciation evolutionary process that creates new species. Divergent Evolution- when related organisms become less alike: Ex: Brown Bears vs Polar Bears Adaptive radiation- members of a species adapt to a variety of different habitats. Example: different finch species Convergent Evolution- Distantly related organisms develop similar features. Ex. Sharks and Whales Mimicry- Evolution of one organisms to look like another

What are some factors that decrease the chance of a population to evolve? 1. Lack of pressure from predators 2. Enough food to feed the population 3. No individuals migrating into the population (In other words: No changes at all)

unit 8 organization of life, plants, and evolution

Documents

convergent evolution

mechanisms of evolution

bresesive allele slide

organisms b

divergent evolution

organisms ability

variation organisms

organisms fitness fitness