1. Ecosystem
a. An environment where organisms live; defined by how the organism interacts with
each other and the environment, boundaries are flexible
b. = smaller units in which the biosphere is divided into
c. Consist of all biotic (living) and abiotic (nonliving)
d. Every organism in an ecosystem changes the ecosystem, change in plants drive
change in animals
i. For example: leaves from tree  fall onto ground and pond  in time,
leaves decay  returning important nutrients to forest floor & introducing
new ones into the pond
2. Ecological Succession
a. A process in which environments constantly change, until “equilibrium” is reached
b. An existing community is gradually replaced by another community, two main
situations:
i. When no previous life has existed that succession is called primary
succession
ii. Succession in areas of previous growth, such as abandoned fields or
forests, is called secondary succession
c. Climax community: a stable collection of plants and animals reached by ecological
succession
3. Land Biomes:
a. Biome is an environment that has a characteristic climax community
b. Land biome is one of two main types the Earth is made up of
c. Tundra:
i. Icy, treeless; covered by mosses, lichens, and
grasses, a few stunted trees,
ii. Permafrost, precipitation occurs in the summer
when animals migrate
d. Taiga:
i. Forested area, cold, wet climate, coniferous trees
ii. Black bears, grizzlies, wolves, moose, elk…
iii. Cold winters, mildly warm summers
e. Temperate Deciduous Forests:
i.
Oak, maple, beech birch = deciduous: shed their leaves in autumn
ii.
Mild climates, a lot of rain, hot summers and cold winters
f. Grasslands:
i. Vast areas covered with grasses and small leafy plants
ii. Seasonal change: wet to very dry
iii. moderate climates, soil very fertile
g. Tropical Rain Forests:
i. Warm, rain year round
ii. South America, southeast Asia, Africa, and central America
iii. Richest animal and plant life
h. Deserts
i. Very little rainfall, Hot and dry wind, landscape is very barren
ii. Only few types of trees, and some insects, scorpions, snakes,
birds and lizards
4. Energy and Nutrients: Building the Web of Life
a. Flow of energy: from sun  producers  consumers
i. Producers: photosynthetic organisms that are able to make their own
food from inorganic substances
ii. Consumers: animals that get their energy either from producers
1. primary consumers: herbivores (plant-eating), feed directly on
producers
2. secondary consumers: usually carnivores (meat-eating), feed
on primary consumers
iii. decomposers: organisms that obtain their energy from non-living organic
matter, bacteria, fungi
iv. As we progress through the food chain, from one trophic level to another,
LESS ENERGY… 10% of each level for the next….90% used
v. Biomass: total mass of all the organisms in a trophic level
b. Ecological pyramids: in order to represent energy relationships
among trophic levels
i. of energy: shows total amount of incoming energy
ii. of biomass: total mass of living tissue per level
iii. of numbers: total number of organism per level
c. Biogeochemical Cycles: process in which nutrients move
through the biosphere (nitrogen, water, oxygen, carbon)
i. Water cycle: evaporate (water  sky), condensate (sky  clouds),
precipitate (clouds  water)
ii. Nitrogen cycle:
1. nitrogen fixation: free nitrogen (in air) changed 
nitrogen compounds (in plants roots)
2. denitrification: animal have eaten the plant and made
animal protein, eventually die and bacterias in the soil break
down the protein  free nitrogen
iii. Carbon cycle:
1. During photosynthesis, plants use CO2 from atmosphere  form
glucose. Consumers & decomposers use glucose in respiration
 release CO2
iv. Oxygen Cycle: during photosynthesis, oxygen is released in
atmosphere. Then used for respiration (animals) release water 
absorbed by plants  respiration  release water…
d. Feeding Relationships: Food chain
i. 3o consumers (Carnivores)  2o consumers (Carnivores)  1o
consumers (Herbivores)  producers (plants) absorb nutrients and
grow
ii. 4o consumers, Scavengers eat  dead animals. Bacteria and fungi
decompose dead tissue returning elements to environment.
Interactions within Community –
- Population: a group of organisms of the same species living in one place (they
interbreed and have fertile offspring)
- Community – a group of many populations living in the same area
- symbiosis – “living together”; organisms living together in a long-term relationship
o Parasitism – an organism (parasite) that's living off of another organism
o Mutualism – both organisms benefit
o Commensalism – one organism benefits; the other is unaffected
- Competition (fight for scarce resources) is a problem
- the limiting factor of an environment is something that's in short supply (can be biotic
or abiotic)
- Predation – one organism (predator) eats another (prey) [extreme parasitism]
Air Pollution –
- Greenhouse Effect = EXCESS CO2
o Melting of polar ice = water level rises (why if water shrinks from solid  liquid
??)
- Depletion of the Ozone Layer
- Global Warming
o Combustion, burn things like fossil fuels, coal, oil, natural gasses
- Acid Rain: caused by gases mixing
• Biodegradable – can be broken down into its basic elements in a small amount of time
• Non-biodegrade – can still be broken down, just takes too long, ex. Pesticides, DDT
Rainforest Destruction:
- mass extinction of species
- food web is so interconnected
- “natural product” drugs
Genetic –
- How traits are passed down from generation to generation
- Gregory MENDEL
- Pea plants: elements of a “model organism” for genetic research
o Easy to grow
o Variations with distinct form ex. purple, white
o Structure of the plant allowed for certain crosses, only had “self”, “pure bread
peas”
- Structure of plants
o Petals: attract the pollinators,
 fragrance is given off at the base of the
petals
 colors of the petals
 nectar
o Anther: makes the pollen (plant sperm)
o Stigma: sticky and helps pollen slide down into
the ovum (it self-pollinates)
o Self-Pollination = “purebreds”
 plant sends pollen to itself
o Cross-Pollination
 Pollen from one plant is sent to the ovum of another
o Separately planted green & yellow seeds
o Green pea plants - when bloomed, cut off the anthers (sperm)
 Now, these are “female plants”
o Yellow pea plants – pain brushes the pollen off into a jar
 Now, these are “male plants”
o Pollinated the green pea plants with yellow pea plant pollen!
o Parents: Green (recessive, female) X Yellow (dominant, male)
Generation
First filial generation
Self-pollinated…second filial generation
Meiosis –
-
-
-
Outcome
ALL yellow (dominant)
1:3 green:yellow
Phenotype: what you see
Genotype: genetic make-up
Homozygous: 2 identical alleles (allele: a form of a gene)
Heterozygous: 2 different alleles
Gametes: reproductive cells
creates genetic variation
has 2 copies of each chromosome (homologous)
gametes are haploid n chromosomes
diploid: when homologous chromosomes are present!
crossing over happens during prophase 1
homozygous parents  ALL HETEROZYGOUS CHILDREN
“dihybrid cross” - alleles segregate independently
Mendel’s laws:
o Law of Segregation – when gametes form, the alleles separate;
 Anaphase I - when homogenous chromosomes separate
o Law of Independent Assortment –
 Prophase I when crossing over
Dominance – one gene per trait with two alleles, one dominant and one recessive
Incomplete dominance – carnations, red flowers (dom., RR) white flowers (rec. rr)
make pink (Rr)
Co-dominance: both traits separate (ex. cow with red hairs & cow with white hairs)
o Human blood types
 Some people have gene for A(Immunoglobulin), some for
B(Immunoglobulin)
 Some people don’t have the gene for either they have O
 Each trait is controlled by two genes, they can have a genotype of
 AA
 BB
 OO
 AB
 AO
 BO
 Can also be writen as (I = Immunoglobulin)
 IaIa
 IbIb
 IoIo
 IaIb
 IaIo or IA i
 IbIo or IB i
o 2 alleles in a genotype because you get one from each parent
Polygenic Traits –
- Hair color, skin color, height
- multiple genes for a single trait
- many, many phenotypes
Determining the sex of an individual –
- chromosomes 1-22: autosomes: same in male and female
- chromosome #23: “sex chromosome”
o men = XY
o females = XX
- sex linked traits: if gene resides on a sex chromosome
- genes far apart from each other on a chromosome are more likely to separate during
crossing over
- The recessive allele on the X chromosome can cause a genetic condition or disorder
(NOT THE Y)
- MORGAN: the discover y of linked traits
- Used fire flies to experiment on and when the phenotypes that he resulted with weren’t
in accordance to the usual ratio of dominant and recessive, he
realized they were “sex-linked” traits
Chromosomal Mutation –
- Deletion – lose a piece of a chromosome
- Inversion – piece of a chromosome is reversed
- Translocation – a piece joins onto a non-homologous chromosome
- Duplication – extra piece of a chromosome
Gene Mutation –
- All happen in germ cell
- point mutation
o could be harmless
o only amino acid might change
o A-T-A-C-A-A-T-G
o U-A-U-G-U-U-A-C