Visualizing Human Bio Ch 1-3

What are the main characteristics of life?

Respond to external stimuli, alter the environment, sense the environment, adapt to the environment, use energy, reproduce, contain materials found only in living organisms, maintain homeostasis, and have a high degree of organization.

What is homeostasis?

A constant internal environment maintained by both conscious and unconscious responses, helping organisms stay alive through feedback systems.

What are the components of a feedback system?

Stimulus receptor (monitors and reports changes), control center (registers the signal and formulates a response), and effector (carries out the response).

What is the smallest unit of life?

Cells, which are contained in a membrane or cell wall.

What is the hierarchy of biological organization?

Atoms, molecules, cells, tissues, organs, organ systems, organism.

What are the three domains of life?

Eubacteria (prokaryotes), archaebacteria (bacteria that live in extreme conditions), and eukarya (eukaryotes).

What are the kingdoms within the domain Eukarya?

Protista, animalia, fungi, plantae.

What is the scientific method?

A logical path to an answer aimed at proving a hypothesis wrong, involving observation, hypothesis formulation, experimentation, data collection and analysis, and communication.

What defines a scientific theory?

A general uniting principle of science upheld by observation and many experiments; a hypothesis becomes a theory when it is not disproved after rigorous testing.

What is statistical significance in an experiment?

An experimental result that would occur by chance in less than 1 in 20 experiments, accepted as a standard in modern science.

What unique physical traits do Homo sapiens possess?

An upright bipedal stance, opposable thumbs, an enlarged brain case, and the capacity for complex speech communication.

When did the common ancestor of primates live?

About 60 million years ago.

What are some key traits of primates?

Fingernails/toenails, stereoscopic vision with forward-facing eyes, and 5-digit hands with opposable thumbs.

When did the ancestors of apes and humans diverge from old-world monkeys?

About 25 million years ago.

What is significant about Australopithecus afarensis?

It was the first member of the family Hominidae, walked upright, had a larger cranium than previous nonhuman primates, and was omnivorous.

What distinguishes Homo habilis from Australopithecus afarensis?

Homo habilis lived nearly 3 million years ago, had larger brains, new types of teeth, and the ability to use and make tools.

What are Homo ergaster and Homo erectus known for?

They lived nearly 2 million years ago and are significant in the evolutionary history of humans.

What are some physical characteristics of Homo Ergaster compared to Homo Habilis?

Homo Ergaster was lighter, had a higher skull bone, thinner cranial bones, a slimmer brow ridge, and a lighter skeleton.

What species migrated out of Africa approximately 1 million years ago?

Homo erectus

What do Omo I and Omo II date modern humans in Africa to?

195,000 years ago

What factors contribute to the formation of race in humans?

Geographic barriers leading to isolation, natural selection, sexual selection, and favored genetic traits.

What is an ecosystem?

Interactions between living and non-living components of a defined area, requiring energy flow, chemical cycling, and nutrient cycling.

How is energy stored in human tissues and cells?

As ATP (adenosine triphosphate).

What is the flow of energy in an ecosystem?

Energy flows from the sun to producers, then to consumers, and finally to decomposers.

What are producers in an ecosystem?

Organisms that assemble usable food molecules through photosynthesis.

What type of organisms are humans classified as?

Heterotrophic consumers.

What are the main producers on land?

Green plants and cyanobacteria.

What is a habitat?

The physical environment where an organism lives, limited by obstacles and competition for resources.

What is a niche?

The role or job of an organism in its community, including its food sources and activity patterns.

What is the significance of the phrase 'like dissolves like'?

It refers to the principle that polar solvents dissolve polar solutes, and non-polar solvents dissolve non-polar solutes.

What elements are most living things primarily made of?

Oxygen, carbon, hydrogen, and nitrogen.

What is the atomic structure of an atom?

Atoms consist of a central nucleus with protons and neutrons, surrounded by a cloud of electrons.

What is the valence shell?

The outermost energy level of electrons in an atom, where bonding occurs.

What are ionic bonds?

Bonds formed through the attraction between positive and negative ions.

What are covalent bonds?

Bonds formed when atoms share electrons to fill their valence shells.

What role do hydrogen bonds play in biology?

They cause attractions between nearby molecules, crucial for DNA structure and protein shape.

What percentage of body weight does water constitute?

60-70%.

What are the important properties of water?

Liquid at room temperature, good solvent, and has a polar covalent bond structure.

What does the pH scale measure?

The concentration of acids and bases, ranging from 0 (acidic) to 14 (basic).

What is the composition ratio of carbohydrates?

1:2:1 ratio of carbon, hydrogen, and oxygen.

What are monosaccharides?

Single sugar molecules, such as glucose.

What distinguishes saturated fats from unsaturated fats?

Saturated fats have no double bonds between carbons and are solid at room temperature, while unsaturated fats have at least one double bond and are liquid.

What are the functions of proteins?

They are formed from amino acids and can act as enzymes to speed up chemical reactions.

What are nucleic acids and their types?

Molecules that encode genetic information; the two types are DNA and RNA.

What is ATP and its role in the body?

Adenosine triphosphate is the energy currency of the cell, storing energy extracted from food.