Contents:
Ecology- the study of the environment and the interactions between environment and living things.
I. Abiotic (non living) Factors
- Light
- Natural disaster (fires, hurricanes…)
- Radiation
- Pollution/ air quality
- H2O
- Atmosphere
- Substratum (rocks, sand, ice and soil)- surface where living things operate
- Minerals
- temperature
II. Biotic (living) Factors
1. Populations- all members of a species (excluding humans) inhabiting a given area
2. Community- all members of all species inhabiting a given area
3. Ecosystem- all members of all species interacting with the abiotic factors in a given area
4. World Biomes- large areas in which ecosystems operate (ex: deserts, oasis, sand dune, tropical rain forest)
5. Biosphere- the part of the world occupied by living organisms
A) Autotrophic Nutrition- (green plants- photo synthesis)- organisms which make their own food.
B) Heterotrophic Nutrition- (all animals, fungi)- organisms which cannot make their own food
1. herbivore- eats plants (has flat teeth)
2. Carnivore- eats meat (has sharp teeth)
A. Predators- hunters, animals that hunt and kill their own prey.
B. Scavengers- animals that eat food killed by predators (ex: vulcher, crow, hyena)
3. Omnivore- eats plants and meat ( sharp and flat teeth)
Symbiosis- relationships between 2 different species
1) parasitism- (+-) one species benefits while the other species is harmed (ex: viruses, athletes foot, tapeworm, mites, fleas, father mites)
2) Mutualism- (++) both species benefit (ex: clownfish and anemone, wrasse (cleaner fish) and coral, lichens -combo organism (algae and fungus)
3) Commensalism- (+0) one species is benefits and the other is unaffected (ex: remora and shark, barnacle and whales)
Habitat- were an organism lives
A. terrestrial- living on land
B. aquatic- living in water
Niche- the role of an organism in the environment (1 species per niche)
Competition- struggle among organisms for various resources
Limiting Factors- resources that are present in a finite supply (keeps population at a certain level)
Ecological Succession (plants)
Pioneer Organism- first plants to inhabit an area usually grasses (lichens- break rock into soil)
Intermediate Stages
Climax Community- last stage of succession, permanent unless destroyed (ex: maple, oak and beech trees)
Biodiversity- the range of living organisms in an area (different species) the more species the healthier the ecosystem
Recycling (material cycles):
nitrogen cycle
water cycle
O2-CO2
Recycling – as done by humans is and effort to reuse non renewable resources (ex: plastic, glass-sand, and metal)
Non reusable things that aren’t recycled fossil fuels (oil, gas, coal)
Human Impact on the Environment:
A) Negative:
1) Pollution
2) Overuse of resources
3) Extinction of species
a) Destruction of habitats-deforestation (cutting down trees)
b) Hunting
4) Global warming (?) – Green House Effect
5) Destruction of the ozone layer
a) Would increase the rate of skin cancer
6) Over population
7) Acid Rain – factory pollution mixes with rain S02 (sulfur dioxide) burning of coal
8) Importation of non native species (invasive species)
a) People transporting and importing foreign creatures (plants or animals) into there area
9) Chemical Control- DDT
B) Positive:
1) Pollution Control
2) Birth control
3) Biological control
4) Breeding of endangered species
5) Animal reserves/ Habitat restoration
Evolution- change over time
I. Inorganic evolution- changes in the earths features
II. Organic evolution- changes in life forms (species)
Paleontology- the study of ancient life
Evidence for Evolution:
a) fossils-remains or traces of once living organisms (at least 10,000 yrs old)
1) actual remains
a) frozen remains(escapes decomposition)
b) tar pits (escapes decomposition)
c) mummification- dried out animals in the desert
d) Amber- fossilized tree sap
2) traces
a) footprints
b) imprints
c) petrified remains- H2O combines with chemicals in rock to form a weak acid, the acid will dissolve the tooth and just leave the rock, sometimes dissolved minerals are carried into the shape of the original remains and crystallize there
b) Comparative Anatomy- comparison of structures to establish a degree of relationships and common ancestry
- bone structures- in vertebrates (any animal with a back bone)
- vestigial structures- structures which had a use ancestrally but that function has been lost over time (ex: hair, toe nails, appendix, coccyx-tail bone)
- Missing links- transition organisms between major groups
*Birds
Fishà amphibiansà reptiles à
Mammals
We don’t have fossils to prove that these changes happened with one exception
Archaeopteryx- fossil (12-18” long) has the features of:
|
Reptilian |
Avian (birds) |
|
Tails with bones |
wings |
|
Scales |
Beak |
|
teeth |
2 legs |
|
|
Feathers |
c) Comparative embryology- comparison of embryos to establish a degree of relationship and common ancestry
-Visual comparison of different embryos shows a striking similarity
Early Human Embryo
- gill slits
- webbed hands and feet
- tail
- 2 chambered heart à 3 à 4
d) Comparative Biochemistry- comparison of molecules to establish a degree of relationship and common ancestry:
1) pig insulin was used to treat human diabetes
2) sheep and cow thyroxin (metabolism hormone) was used to treat human thyroid deficiency
3) pig valves are used to replace defective human heart valves
4) Human DNA is 97.5% similar to chimpanzee DNA
E) Geographical Isolation- natural barriers (physical features which separate populations)
a. Darwin’s Finches (finches=birds)- only found in the Galapagos Islands( in the pacific ocean)
- 1859- Darwin’s theory of evolution
- they differed in size and shape of their beaks
- Darwin figured out: there were slight differences in the size and shapes among the ancestral finches
- Some traits were better adapted to one set of environmental conditions, while other beak variations were better adapted to different environmental conditions
- Geographic Isolation- leads to speciation
- Speciation- the formation of new species
b. Marsupials in Australia
- types of mammals
A. marsupials- have a pouch (give birth prematurely) – more dangerous
B. placental- have a placenta (entire birth is internal)
- Continental Drift- 2 separate continents:
A. North America, Europe, Asia, Greenland
B. South America, Africa, India, Australia, Antarctica
- placentals spread out
- they were in competition with the marsupials and since placentals reproduce better most of the marsupials died out
- there are only marsupials on Australia because placentals didn’t get to Australia because when they spread out Australia was already and island
Tectonic plates
Theories of Evolution:
Lamarck- Theory of Acquired Characteristics:
1. structures arise according to need
2. the size of structures is proportional to their frequency of use (use and disuse)
3. features which develop during an organisms life time are passed on to its offspring
Weisman- disproved the Theory of Acquired Characteristics
B. Darwin- Theory of Natural Selection (1859)
1. there is an over production of offspring
2. the adult population tends to remains constant
3. there is a struggle for survival (competition) among the offspring
4. the offspring with the most favorable adaptations are likely to survive- survival of the fittest
5. the survivors tend to reproduce and to pass the favorable traits on to their offspring
6. over time favorable adaptations tend to increase in frequency
C. Modern Evolution
Darwin + Causes of Variations (mutations)
Rates of Evolution:
gradualism- evolution occurs at a slow steady pace
punctualism- evolution occurs in grief intense bursts with long periods of inactivity in between
Pepper Moth
DDT
Origin of Life on Earth:
1. Divine Origin (god)-not scientific
2. Came from outer space- not scientific
3. Spontaneous generations- life arose from non living matter
Redi- his experiment with the 3 jars of meat and flies
He disproved spontaneous generations but nobody believed what he said. They thought the reason that there were no flies in the closed jar was because the air couldn’t get into the jar.
Pasteur- he put broth in a weird shaped flask. Then in one of the twists of the tube part of the flask he put a little water there. The micro organisms that flew into the flask didn’t get to the broth and only stayed in the water and reproduced there. This proved that the micro organisms didn’t come from the broth yet they were attracted to the broth. When he disproved spontaneous generations people believed him.
Today: scientists believe that spontaneous generation is the bet theory to how life came to earth. They think spontaneous generation could have happened billions of years ago (because of the different conditions that there was back then), but today spontaneous generation can’t happen.
Oparin- Heterotrph Hypothesis - said that spontaneous generation could have happened years ago but it can’t happen today because of different conditions:
Temperatures were much higher back then- the earth was in a molten (liquid rock) state.
the primitive atmosphere consisted of H2O vapor (steam), H2 (hydrogen), CH4 (methane), ), CH4 (ammonia)
earth was bombarded by large doses of ultraviolet radiation (this probably happened because there was no ozone layer to block some of the ultra violet radiation from entering the earth’s atmosphere)
earth started to cool, forming a crust
the water vapor condensed resulting in long periods of rain (sometimes centuries of rain) this rain water filled depressions (low areas) in the earths crust, forming the primitive oceans
gases from the atmosphere dissolved in the oceans under the influence of ultraviolet radiation and electric energy(lightning storms) some of these gases combined to form simple organic compounds (monosaccharide and simple amino acids)
Urey and Miller- built a chamber into which they put H2O, H2 ,CH4, CH4 , they gently heated the mixture and circulated it and passed and electric spark through it, a week later they opened up the chamber and they saw what Oparin said they would see (monosaccharide and simple amino acids), but this didn’t prove Oparin’s theory was correct because it wasn’t 100% the conditions that Oparin said there was a long time ago. They didn’t use any ultraviolet radiation. But Oparin still could be right we just don’t know for sure.
overtime simple organic molecules combined to form larger more complex organic compounds (aggregates)
at some point aggregates were able to replicate (this is life)
Nutrition: a. the first organisms were heterotrophs (don’t make their own food)
b. autotrophs evolved later
Respiration: a. the first organism were anaerobes (organism which don’t require oxygen in order to live)
b. aerobes (organisms that need oxygen in order to live) evolved later
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