Science STAAR NotebookBiology - Category 3

Science STAAR Science STAAR NotebookNotebook

Biology - Category 3Biology - Category 3Biological Evolution and

Classification

TaxonomyTaxonomy• Classification Levels:

• Test Taking Hint: you have to know the order, memorize a mnemonic!!!

• In scientific notation, the first name is always the genus, the second name is always the species.– Example – Homo sapien

Genus Species

STAAR QuestionSTAAR QuestionWhich of the following is the most specific group used to classify organisms?

Hint:A Kingdom B Class C Genus D Order

Why is Taxonomy Why is Taxonomy Important?Important?• Taxonomy provides order by accurately & uniformly

naming organisms

• Helps scientists identify animals which are similar to each other.

• Prevents misnomers such as starfish & jellyfish that aren't really fish

• When new animals are discovered, there is a common way of naming them so ALL people understand.

• Uses same language (Latin or some Greek) for all names

• All other animals share at least a genus; only humans have there own genus and species.

TaxonomyTaxonomy

•The more levels that organisms are in together the more closely related they are.– For example the bullfrog, Rana

catesbeiana is most closely related to northern leopard frog, Rana pipiens because they have the same genus name.

Taxonomy GlossaryTaxonomy GlossaryKNOW THESE TERMS!KNOW THESE TERMS!

• Vertebrate=Vertebrate=backbonebackbone

• Invertebrate=no backboneInvertebrate=no backbone

• Segmentation=repetitive Segmentation=repetitive segmentssegments (ex: worm) (ex: worm)

• Unicellular=single celled organism (ex: bacteria)Unicellular=single celled organism (ex: bacteria)

• Multicellular=many cells (ex: cat)Multicellular=many cells (ex: cat)

• AutotrophicAutotrophic=make their own food (ex: plants)=make their own food (ex: plants)

• Heterotrophic=can’t make their own food (ex: animals)Heterotrophic=can’t make their own food (ex: animals)

• Mobile=Mobile=movemove

• Immobile=can’t moveImmobile=can’t move

• Bilateral symmetry=Bilateral symmetry=mirrormirror images (ex: butterfly) images (ex: butterfly)

• RadialRadial symmetry=duplicate body parts (ex. Starfish) symmetry=duplicate body parts (ex. Starfish)

The Six KingdomsThe Six Kingdoms1. Archaebacteria – unicellular (one-celled) prokaryotes that often live in extreme environments. Some are autotrophs (make their own food), some are heterotrophs (consume their food). Examples: bacteria that live in hot springs.

2. Eubacteria – unicellular prokaryotes that may or may not make their own food. Examples: bacteria that cause strep throat.

3. Protista – mostly one-celled eukaryotes. However, there are a few protists that are multicellular. Protists may be autotrophs or heterotrophs. Lack tissues like roots or leaves. Examples: amoebas, slime molds, and algae.

4. Fungi – most are multicellular and eukaryotes, although there are a few unicellular fungi. All fungi are heterotrophs (absorb their food) with cell walls. Examples: mushrooms, yeasts, and molds.

The Six Kingdoms (con’t)The Six Kingdoms (con’t)5. Plantae – multicellular eukaryotes. They have cell walls and specialized tissues and organs. Plants are autotrophic by performing photosynthesis. Examples: mosses, ferns, trees, and grasses.

6. Animalia – multicellular eukaryotes. They are heterotrophs (consume their food). They have specialized tissues and organs. They are motile (can move around). Examples: worms, insects, fish, birds, and mammals, humans.

STAAR QUESTIONSTAAR QUESTION

EvolutionEvolutionDefinition – change in a population over time.Evidence of evolution:

1. Fossils – traces or remains from an organism that lived long ago.

2. Biogeography – geographic distribution of organisms

3. Homologies – similarities between organisms show common ancestry, examples:

a. Anatomical similarities – structures that organisms have in common. a. vestigal structures - structures that are no longer

functioning but are still present.

EvolutionEvolution– Evidence of evolution (con’t):

b. Molecular similarities – -DNA Sequences (strongest piece of evidence) – comparing the amino acid sequences of different proteins to compare the relationships

- For example, Cytochrome c is a protein found in all aerobic organisms.

c. Physiological Similarities – - Homologus structures – structures that are similar in organisms but have different functions.

i.e. bones in the arms of birds, mammals, and amphibians

d. Developmental similarities – -Embryology – study of embryos. Scientists

conclude that since many organism’s embryos look similar, that we evolved from a common ancestor.

STAAR QuestionSTAAR QuestionThe limbs of several organisms are shown in the illustrations below. Scientists sometimes compare the limbs of these organisms to look for evidence of common ancestry.

These limbs provide evidence of common ancestry because they – A have the same basic structureB perform the same functionC are the same sizeD are parts of mammals

STAAR QuestionSTAAR Question

Natural SelectionNatural Selection• A mechanism for evolution.

• Traits that help an organism survive in a particular environment are “selected” for in natural selection

• A chance mutation in an individual can lead to natural selection in a population and increase the frequency of those genes.

STAAR QuestionSTAAR Question

Some organisms have genes that improve their ability to survive and reproduce. If the genes also help their offspring survive and reproduce, then which of the following will most likely increase?

A The frequency of the genes in one individualB The frequency of the genes in the populationC The number of genes in one chromosomeD The number of genes in the species

Natural SelectionNatural Selection• Natural selection rests on three

facts:

1. Organisms produce more offspring than can survive, ex: 1 out of 1,000 sea turtle hatchlings will make it to adulthood.

2. Individuals vary in their characteristics due to genetic variation (differences in DNA that produce different traits in the organism).

3. Many characteristics are inherited by offspring from their parents, ex: genes that improve an organisms ability to survive and reproduce.

Types of Natural SelectionTypes of Natural Selection• Long term survival of any species is possible only if the

organisms can reproduce successfully.• Adaptation – how organisms change to fit their environment, ex:

mimicry – scarlet king snake and the eastern coral snake. Which one is poisonous?

• Genetic drift – change in the frequency of alleles in a population.• Speciation – the process by which new species arise.• Extinction – the end of a species.

Changes in a Changes in a singlesingle organism:organism:1. Mutations – change to the DNA of an organism; can be passed to offspring and add variation to the population

2. Recombination - Crossing over of genetic material during meiosis; creates new sequences of DNA

1. Gene Flow – organisms migrate to other populations. Ex: this new bug will add variation to the new population.

2. Genetic drift – random changes in the allele frequencies in a population

Changes in a population:

STAAR QUESTIONSTAAR QUESTION

Why is natural selection Why is natural selection important? important? • The earth’s environment is constantly changing, so animals

must change with it.

• Changes to the animal can be slight, but if they help the animal survive, it will be more likely to reproduce and pass on that gene. – Example: Wooly mammoth and elephant

Questions:1. What is the difference between a wooly mammoth and an

elephant? 2. How were their environments different? 3. Why did the mammoth not survive after the ice age?

STAAR QuestionSTAAR QuestionTraits that enable an organism to survive and reproduce in its environment are known as -

A MutationsB VariationsC AdaptationsD Speciation