Download File - Tabb Life Science

EVOLUTION
Charles Darwin - The Origin of Species by Means of Natural Selection (1859); Father of Evolution
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Darwin discovered that the finches on the Galapagos Islands were the same except for their
beaks. The beaks had adapted according to the food that was available.
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Darwin lacked information about inherited traits and variation. Scientists now know that variation
happens as a result of differences in genes. Changes happen when organisms produce offspring
over many generations. Some genes make an organism more likely to survive.
1. Adaptation – a characteristic that improves an individual’s ability to survive and reproduce in a
particular environment. Adaptations can be physical or behavioral
a. Physical – frogs have green or brown skin to help them blend in w/ leaves or the forest
floor , red eyes to help see at night, red coloring to warn predators it may be poisonous
b. Behavioral – to find food, protect itself or to reproduce
2. Species – a group of organisms that are closely related and can mate to produce fertile offspring.
3. Evolution - is the process in which populations gradually change over time. Sometimes new species
arise.
a. Evidence used to support evolution include
i. The fossil record
ii. Radioactive Dating
iii. Anatomical similarities (skeletal structures)
iv. Embryological Evidence
v. DNA (chemical evidence)
vi. Distribution of organisms
4. Fossil – the remains or physical evidence of an organism preserved by geologic processes
a. Usually form when a dead organism is covered by a layer of sediment. There are body
fossils, Trace, mold, & cast.
5. Fossil record – a historical sequence of life indicated by fossils found in layers of the Earth’s crust.
a. Organizes fossils by their estimated ages and physical similarities. It also provides evidence
about the order in which species have existed throughout history.
6. Trait – a genetically determined characteristic.
7. Selective breeding – the human practice of breeding animals or plants that have certain desired
characteristics
8. Natural selection – the process by which individuals that are better adapted to their environment
survive and reproduce more successfully. Also known as Survival of the Fittest
a. Natural Selection has four parts (now supported by genetics)
i. Over population - species produce more offspring then will survive to reproduce
ii. Individuals within a population have slightly different traits
iii. Individuals within a population compete w/ each other for resources
iv. The better equipped are more likely to survive, reproduce, and pass on traits
9. Generation time – the period between the birth of one generation and the birth of the next generation.
10. Speciation – the formation of new species as a result of evolution.
a. The three stages are:
i. Isolation/Separation
ii. Adaptation
iii. Division
11. Homologous structures – anatomical features that have similar evolutionary origins and exhibit
similar anatomical patterns (bird wings, human arms, whale flippers, deer forelimbs)
12. Analogous structures - function similar but are anatomically dissimilar (bird wings & butterfly wings).
13. Vestigial Structure (or organ) performs little or no function but may have in ancestors. In chimps,
gorillas & orangutans for example the appendix is an intestinal sac that helps digest tough plant
material. In humans it does not function.
14. Population – group of the same species living in the same place.
a. Populations of all species are limited by starvation, disease, competition & predation.
15. Age of Earth – scientists believe that our planet is 4.6 billion years old
CLASSIFICATION
Carolus Linnaeus – (1700’s) created the (7) levels of classification that is still used today:
1) Kingdom
2) Phylum
3) Class
4) Order
5) Family
6) Genus
7) Species
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Classification - grouping of organisms based on similar observable characteristics
Taxonomy- science of classifying organisms
Binomial nomenclature- system that gives each organism a 2-part name (Genus & species)
Genus- group of closely related organisms
Species- organisms that can mate & produce fertile offspring
Autotroph- an organism that can make its own food (producers)
Heterotroph- an organism that gets food by eating other organisms
Dichotomous Key – an aid that is used to classify organisms and that consist of the answers to a
series of questions
9. Kingdoms (6)
1) Archaebacteria – single celled, prokaryotic ( no nucleus), autotrophs & heterotrophs, live in
harsh, ancient (first living organisms)
2) Eubacteria – single celled, prokaryotic, autotrophs & heterotrophs, common bacteria
3) Protists – single celled, eukaryotic (has nucleus), plant-like, animal-like & fungus-like
4) Fungus – most multicellular (except yeast), eukaryotic, all heterotrophs (absorb nutrients
from decomposing organic matter), rigid cell wall (like plants) but no chlorophyll.
5) Plantae – all multicellular, autotrophs and eukaryotic. Do not move actively
6) Animalia – all multicellular, heterotrophs and eukaryotic.