What does the organisms and body systems part of the Florida Biology 1 EOC cover?

It covers how organisms maintain homeostasis through feedback, the cardiovascular system and the factors affecting blood flow, the immune system (including vaccines and antibiotics), the nervous system and the major parts of the brain, and plant structure and function (transport, support, reproduction, and photosynthesis). This is part of Reporting Category 3, Organisms, Populations, and Ecosystems, which is the largest at about 40 percent of the exam.

What is the difference between negative and positive feedback?

Negative feedback opposes a change and returns a variable toward its set point, which is how most homeostasis works (sweating to cool down, insulin lowering blood sugar). Positive feedback amplifies a change, pushing it further to complete a process quickly (childbirth contractions, blood clotting). The signature of negative feedback is that the response reverses the change and restores the normal range.

What do arteries, veins, and capillaries do?

Arteries carry blood away from the heart, usually under high pressure; veins carry blood back to the heart; and capillaries are the tiny, thin-walled vessels where exchange of gases, nutrients, and wastes happens between blood and cells. Blood flow is affected by heart rate, exercise, vessel diameter (narrowing raises resistance and reduces flow), blood pressure and volume, and disease such as clogged arteries.

Why do antibiotics work on bacteria but not viruses?

Antibiotics attack structures and processes of bacterial cells, such as the bacterial cell wall. Viruses are not cells and lack those structures, so antibiotics do not affect them. Viral infections rely on the body's own immune response or vaccines. The immune system has nonspecific defenses (skin, inflammation, engulfing cells) and specific defenses (antibodies and memory cells); vaccines use a harmless form of a pathogen to build memory cells in advance.

FloridaBiology

Florida Biology 1 EOC organisms and body systems: a complete overview of homeostasis, the cardiovascular, immune, and nervous systems, and plant structure

Q: What are the major parts of the brain and their functions?

The cerebrum controls thinking, the senses, and voluntary movement; the cerebellum controls balance, coordination, and smooth movement; and the brain stem controls automatic functions like heartbeat and breathing. The nervous system also coordinates the stimulus-response pathway (stimulus detected, signal to the central nervous system, signal to effectors, response) and supports homeostasis.

A deep-dive guide to the organisms and body systems half of Reporting Category 3 of the Florida Biology 1 EOC: homeostasis and feedback, the cardiovascular system, the immune system, the nervous system and brain, and plant structure and function, with the item types the EOC uses.

Generated by Claude Opus 4.816 min readNGSSS SC.912.L.14Updated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

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What the organisms and body systems content demands
Homeostasis and feedback
The cardiovascular system
The immune system
The nervous system and brain
Plant structure and function
Check your knowledge

What the organisms and body systems content demands

The organisms and body systems content opens Reporting Category 3, Organisms, Populations, and Ecosystems, the largest reporting category on the Florida Biology 1 EOC at about 40 percent. This half covers how individual organisms work and stay alive: keeping internal conditions steady, moving materials, defending against disease, sensing and responding, and (in plants) carrying out their life functions. The recurring themes are structure and function, systems and system models, and stability and change.

This guide ties together the matching topic pages, each with its own practice questions: homeostasis and feedback, the cardiovascular system and blood flow, the immune system, the nervous system and the brain, and plant structure and function.

Homeostasis and feedback

Homeostasis is the maintenance of a stable internal environment. It works mostly through negative feedback: a change is detected and the body responds to reverse it (sweating when too hot, insulin lowering blood sugar, glucagon raising it). Positive feedback amplifies a change (childbirth). Homeostasis needs body systems working together, and it keeps enzymes at their optimum so cells function.

The cardiovascular system

The heart pumps blood through vessels: arteries carry blood away from the heart, veins return it, and capillaries are where exchange happens. Blood transports oxygen, nutrients, wastes, hormones, and immune cells. Blood flow is affected by heart rate, exercise, vessel diameter (narrowing raises resistance, lowers flow), blood pressure and volume, and disease (clogged arteries).

The immune system

The immune system has nonspecific defenses (skin, inflammation, engulfing white cells, acting against any pathogen) and specific defenses (antibodies and memory cells that target a particular pathogen and respond faster next time). Vaccines use a harmless form of a pathogen to build memory cells in advance. Antibiotics kill bacteria by attacking bacterial cell structures, so they do not work on viruses, which are not cells.

The nervous system and brain

The nervous system runs the stimulus-response pathway: stimulus detected, signal to the central nervous system, signal to effectors, response. The brain's major parts are the cerebrum (thinking, senses, voluntary movement), the cerebellum (balance and coordination), and the brain stem (automatic functions like heartbeat and breathing). The nervous system also coordinates homeostasis.

Plant structure and function

A plant's organs match functions: roots anchor and absorb water and minerals, stems support and transport, leaves carry out photosynthesis (broad and flat with many chloroplasts and stomata for gas exchange), and flowers handle reproduction. Xylem carries water up from the roots; phloem carries sugar from the leaves.

The organisms and body systems content of the Florida Biology 1 EOC covers homeostasis (a stable internal environment maintained mainly by negative feedback, which reverses a change, as in body-temperature and blood-sugar control, versus positive feedback, which amplifies); the cardiovascular system (the heart, arteries carrying blood away, veins returning it, capillaries for exchange, blood transporting materials, and blood flow affected by heart rate, exercise, vessel diameter, and disease); the immune system (nonspecific defenses like skin and inflammation, specific defenses with antibodies and memory cells, vaccines building memory in advance, and antibiotics working on bacteria but not viruses); the nervous system (the stimulus-response pathway and the cerebrum, cerebellum, and brain stem); and plant structure and function (roots, stems, leaves, and flowers, with xylem carrying water up and phloem carrying sugar). The recurring theme is structure and function.

Check your knowledge

A mix of recall and reasoning questions covering organisms and body systems. Attempt them under timed conditions, then check against the solutions.

Define homeostasis. (1 mark)
Explain how negative feedback keeps blood sugar stable after a meal. (2 marks)
State the function of arteries, veins, and capillaries. (3 marks)
Explain why blood flow increases during exercise. (2 marks)
State the difference between a nonspecific and a specific immune response. (2 marks)
Explain why antibiotics do not work against viruses. (2 marks)
State the function of the cerebrum, cerebellum, and brain stem. (3 marks)
State the function of xylem and of phloem. (2 marks)
Explain why a leaf is broad and flat with many chloroplasts. (2 marks)

Solutions

Q1: The maintenance of a stable internal environment despite changes in the surroundings.
Q2: Rising blood sugar is detected, the pancreas releases insulin, which lowers blood sugar back toward normal (reversing the change).
Q3: Arteries carry blood away from the heart; veins carry blood back to the heart; capillaries are where exchange of gases, nutrients, and wastes occurs.
Q4: Heart rate increases (and vessels to muscles widen), so blood flow rises, delivering more oxygen and glucose to active muscles and removing carbon dioxide and heat.
Q5: Nonspecific defenses act the same way against any pathogen (skin, inflammation, engulfing cells); specific defenses target a particular pathogen with matching antibodies and memory cells.
Q6: Antibiotics target bacterial cell structures and processes; viruses are not cells and lack those structures, so antibiotics do not affect them.
Q7: Cerebrum: thinking, senses, and voluntary movement; cerebellum: balance and coordination; brain stem: automatic functions like heartbeat and breathing.
Q8: Xylem carries water and minerals upward from the roots; phloem carries sugars made in the leaves to the rest of the plant.
Q9: The broad, flat shape gives a large surface area to absorb light, and the many chloroplasts capture that light for photosynthesis.

Sources & how we know this

Next Generation Sunshine State Standards: Science (Biology 1) — Florida Department of Education (2024)
Biology 1 End-of-Course Assessment Test Item Specifications — Florida Department of Education (2024)