Notes

a stem cell can become any cell Zygote / fertilized egg – the first cell of an organism - divides through mitosis
Embryo - Earliest stage of development (up to 8 weeks)
Fetus - Later stage of development (9th week and up)
meiosis has genetic variation mitosis doesn't
Genetic Recombination/
Crossing Over -
the exchange (swapping) of genes between chromosomes in meiosis
Increases genetic variation
Fertilization - the process in which a new cell is formed when two gametes (sex cells) –sperm and egg fuse together. Two types of Fertilization:
Internal Fertilization - sperm fertilizes egg inside of organism
External Fertilization - sperm fertilizes egg outside of organism
Zygote - the first cell of an organism, it implants in uterus where it grows and develops
The circulatory system - circulates blood, which carries oxygen and nutrients to cells and removes waste.
The respiratory system - brings oxygen into the body and removes carbon dioxide.
The digestive system - breaks down food into usable nutrients and eliminates waste.
The musculoskeletal system - provides support, helps with movement, and protects internal organs.
The nervous system - controls and coordinates all body functions, sends and receives signals to and from the brain and other parts of the body.
The endocrine system - produces hormones that regulate various functions in the body, including growth, metabolism, and mood.
The urinary system - filters waste from the blood and eliminates it from the body as urine.
The integumentary system - protects the body from external harm, helps regulate body temperature, and senses the environment.
The reproductive system - produces and transports reproductive cells and is responsible for the continuation of the species.
Variation- a different form of something
Genetic variation leads to the protein variation that leads to trait variation
(DNA → PROTEIN → TRAIT)
genetic variation is change and asexual does not have that
female reproductive system Estrogen- female sex hormone that stimulates release of egg
Progesterone- female sex hormone that thickens and maintains the uterus lining to prepare for pregnancy
allergies Production of antibodies against harmless substances:
Over-reaction to harmless compounds (allergens)
Proteins on pollen
Proteins from dust mites
Proteins in animal saliva
Body mistakenly thinks they are attackers
Inflammatory Response
Causes the production of histamines leading to an allergic reaction
Rashes, sneezing, burning eyes, asthma attack

Antibody - a blood protein produced in response to and
counteracting a specific antigen. Antibodies circulate in
the blood, recognize foreign substances like bacteria and
viruses, and mark them for destruction.