Transcript OGT Cram Session 2 Biology

OGT Cram Session
2
Structure of Ecosystems/Levels
of Organization
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Organism – individual living (biotic) thing
Population – group of organisms, all of one
species, which live in the same place and the
same time
Community – all the populations of different
species, same place, same time
Ecosystem – Populations of plant and animals
that interact with each other in a given area
and with the abiotic parts (non-living)
Biosphere – The portion of Earth that
supports life
Levels of Organization
(cont.)
I. Ecosystems
Biomes
A. Tundra
This fact has been on 3 OGT
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Extremely cold climate (-34 degrees
C to 12
tests!
degrees C)
Low biotic diversity
Simple vegetation structure
Limitation of drainage
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Short season of growth and reproduction
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B. Marine
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Cover ¾ the planet
1. Oceans
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2. Coral Reefs
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Largest of all
ecosystems
Very diverse
Coral is dominant
organism
Ex. Great Barrier
Reef
Estuaries
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Where freshwater
rivers meet the ocean.
Fertile soil produces
diversity
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C. Freshwater Biomes
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1. Ponds, Lakes, Streams
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D. Taiga
Stretches across Canada, Northern Europe
and Asia
 Soil is acidic and has few nutrients
 The abundance of evergreen trees provide
shelter for many large animals
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Lynx, elk, caribou, wolves
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E. Desert
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Hot days
Cold nights
Little precipitation
Low biodiversity
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F. Rainforest
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Hot temps
High precipitation
High diversity
Contain species not
yet discovered
Being destroyed by
deforestation
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Kills animals
Reduces amount of
oxygen
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G. Deciduous Forest/Temperate
70-150 cm of rainfall
 Deciduous trees
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Leaves turn color in fall
 Leaves fall off in winter
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Squirrels, mice, bears
Biome Locations
Succession
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Primary Succession
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When organisms colonize barren land (rock)
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Secondary Succession
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Areas that previously contain life
Soil already exists
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Pioneer species – lichen break down rock
Small ferns, fungi, and insects appear after lichen die
Example: after a fire has burned a forest
Climax Community
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Stable mature community
Density-dependent
factors
 Disease
 Competition
 Parasites
 Food availability
Larger and closer a group is
the greater the effect.
1.
Density-independent factors
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Most are abiotic
Temperature
Disasters: floods,
storms, drought,
pollution
Check this out…….(turn on
volume)
http://www.geowords.org/ensci/imagesbook/04_
03_succession.swf
Food Webs/Food Chains
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Food webs show what all organisms eat.
a. Increase in the owl population
A. The mouse population has
increased
Food Webs/Food Chains
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Food Chain is a straight line and only show
1 possible path of the food web
Food Web/Chain Key Points
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If you get rid of an animal from the food
web/food chain, the animal that eats the lost
animal will decline in numbers.
If you introduce an animal/organism to the
food chain all animals who eat the new
animal/organism will increase in numbers.
If you introduce a species that eats the same
organisms as another already in the food
chain, then the animal already in the food
chain will decline in numbers. (The visa versa
is also true.)
Animal Relationships
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Mutualism = Both animals benefit
Commensalisms = One animal benefits, the
other is not harmed.
Parasitism = One animal benefits, the other is
harmed!
Carnivore = eats meat
Herbivore = eats plants
Omnivore = eats both
Producers = make their own food (green)
Consumer = eat producers
Mutualism = both organisms
benefit
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Yellow-billed oxpeckers feed on ectoparasites on the hide of a grazing bull
hippopotamus.
Parasitism
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A parasite feeds on a
host. Usually the
parasite does not kill the
host (not immediately)
Ex) tics
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(endoparasites-inside the
host)
Energy Pyramid
Commensalism
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One-sided relationship.
One species benefits
with out harming the
other species
Competition
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When 2 or more species share similar
characteristics and require the same resources
they compete.
Alien species- non-native species, reproduce out
of control because they have no natural
predators
Carrying Capacity
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The population of a species that an area will
generally support
Usually there is equilibrium-a balance among
species
Autotrophs
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“Automatically” make their own food
Producers
Plants-that can make their own food by
photosynthesis
Heterotrophs
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Cannot make their own food.
Animals must obtain food
Herbivores-plants
 Carnivores-meat
 Omnivores-Both
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Environmental Problems
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Pollution-rise of industry has led to increased air
and water pollution
Ozone Layer
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Ozone absorbs the suns UV rays
Without ozone, the UV rays would lead to
genetic mutations in all living cells
CFC’s break down the ozone layer
Pesticides
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Poisonous chemicals to help control insects, but
they become part of the water and soil harming
other living things
Acid Rain
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Pollutants in the atmosphere get washed out of
the air when it rains
These pollutants endanger the environment
Here’s What they (OGT) has
asked in the last 4 years………
Cell Theory
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All organisms are composed of
one or more cells
 2. The cell is the basic unit of
organization of organisms
 3.All cells come from
preexisting cells
Prokaryote
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Prokaryotes: No membrane
bound organelles (especially
nucleus)
 a.
Bacteria (Kingdom Monera)
 b. DNA is just “floating” around
along with ribosomes
 c. Mostly unicellular organisms
Eukaryote
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Eukaryotic: cells containing
membrane-bound organelles
 a.
mostly multicellular
 b. some unicellular (algae, yeast)
 C. have organelles: structures
with special functions in the cell
 D. Nucleus: largest in animal cells
Has
Nucleus
Ribosomes
and DNA
No Nuclear
Membrane
Cell Structure
Cell Structures
 1.
Cell wall: rigid layer of
nonliving material that
surrounds the cells of plants
 Made
of cellulose
 Protects and supports the cells
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Cell membrane: Boundary
that protects the cell from
the environment & controls
what comes in and out
 All
cells have
 Like a screen door
3. Nucleus: control center for the
cell
4. Ribosomes: grain like
bodies on the ER & in the
cytoplasm
5.Endoplasmic Reticulum: (called ER)
carry proteins and materials within the
cell
6. Golgi Body: receives and
packages proteins from ER and
distributes around cell and body
(mailroom)
7. Cytoplasm: clear gelatinous fluid
inside a cell
8. Vacuoles: storage area of the cell
Plant has one large vacuole
Stores food, waste, & enzymes
9. Mitochondria = powerhouse of the cell;
where cell energy comes from.
10. Chloroplasts: ONLY IN
PLANTS captures sunlight and
produces food for the cell
11. Flagella = used for
movement
12. Cilia = used for movement;
tiny hair-like structures; found
on cells that need to move
mucus
D. Absence of a nuclear
membrane
B. Viruses require a host cell to
reproduce.
C. flagellum
B. flagella
Questions they (OGT) has
asked the last 4 years.
D. Place the rabbit in a cage
with a heated floor.
B.
D.
Evolution
Charles Darwin (1809-1882)
1. Natural Selection
a.
2.
3.
“Only the strongest survive”
Darwin hypothesized that when
animals had traits that helped them
live, they would pass them on to their
offspring.
Animals who did not possess these
traits died.
Darwin’s Example
1.
2.
Darwin noted the different beak
structures of finches depended on the
island they came from.
Finches who lived on islands plentiful in
nuts and berries had different beaks
than finches who lived on islands
plentiful in insects.
Even though all these birds are finches
they developed different beaks
depending on the plentiful food source
of specific islands.
Examples of Natural
Selection
Galapagos Iguanas
1.
a.
b.
c.
d.
e.
Some iguanas have evolved
to eat algae.
Some iguanas have
developed large claws to
help them cling to rock.
These iguanas evolved
from other iguanas
because they need those
two traits to survive.
The algae eating, long
clawed iguanas passed
these trait on to their
young.
Iguanas not having that
trait.
Everyday green iguana
Galapagos marine iguana
Other adaptations
1.
Camaflouge
a. Enables species to
blend in with their
surroundings.
Can you find the snake’s head?
2. Mimicry – enables a
species to look like
other species
What part of the plant is this?
It’s not part of the plant
at all, it’s an insect.
Darwin Hypothetical
1.
2.
3.
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Let’s say there was a new “killer” virus that affected dogs.
This flu bug only affected dogs with long hair. So, if a dog
had long hair (more than ¾ inch long) it would get the virus and
die.
In 20 years, will all dogs have long or short hair? WHY?
All dogs would have short hair because all the long hair dogs
have died from the virus. There would only be short haired
dogs mating with short hair dogs.
You could say all dogs with short hair were “naturally
selected” to live. The dog species has evolved from having
both short and long hair to having only short hair.
1.
Populations evolve not individuals.
B.
C. Had a higher survival rate
than light moths in the same
area
One last thing the OGT might
get you on……
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Jean Baptiste Lamarck (1744-1821)
Came before Darwin
 Had some of the same ideas as Darwin
 No one ever believed him.
 Died in obscurity and poverty.
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Genetics
1. The dominant trait will always be visible
2. Dominant-always masks the recessive;
represented by uppercase letter (T, H, D, R)
3.
Recessive-will be masked by dominant;
represented by lowercase letter (t, h, d, r)
-For a recessive trait to be visible, there
must be two (tt, hh, dd, rr)
DD
dd
Dd
Punnet Squares
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Cross a homozygous dominant with a
homozygous recessive.
HH x hh
h
H
H
h
h
H
H
h
h
h
H
Hh
Hh
H
Hh
Hh
OGT Tricks
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Sometimes they give you a recessive allele like
c
this: C
c
C
is the same as a “c”
A. O%
D. 100%
SEX alleles
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Males – XY
Females – XX
Recessive diseases
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Diseases that are recessive on the X chromosome
INFO:
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Sex inherited diseases
Females can not get diseases that appear on Y
chromosome
 Males are more likely to get a recessive disease
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If the recessive allele appears on the X males get disease
Females are less likely to get a recessive disease
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If recessive allele appears on one X chromosome the other X
chromosome can cover it with a dominant allele
How to Read Pedigrees
Affected male
Unaffected male
Unaffected
female
Female carrier, She
does not have
Disease but can
pass it on to her
kids.
Pedigrees = a chart that shows you the family
history of passing traits