Honors Biology Semester 1 Review

What is biology?

The study of life and living things, from single cells to human activity on Earth

Observation (scientific method)

Using the five senses to notice and describe phenomena

Question (scientific method)

A problem or inquiry based on observations

Hypothesis

A testable, tentative scientific explanation based on prior knowledge

Controlled experiment

An experiment where one variable is changed while others are kept constant

Independent variable

The variable deliberately changed by the scientist

Dependent variable

The variable that is measured in the experiment

Controlled variables

All variables that remain constant in an experiment

Control group

The group that does not receive the independent variable and is used for comparison

Experimental group

The group that receives the independent variable

Data/analysis

Collected results and interpretation of an experiment

Conclusion

Final statement that evaluates results and restates the hypothesis

Characteristics of living things

Made of cells, reproduce, have DNA, grow and develop, use energy, respond to stimuli, maintain homeostasis, evolve

Homeostasis

Maintaining stable internal conditions for survival

Metabolism

The sum of all chemical reactions in an organism

Monomer

Small molecule that combines to form polymers

Polymer

Large molecule made of many monomers

Carbohydrate monomers

Monosaccharides

Protein monomers

Amino acids

Lipid building blocks

Fatty acids

Nucleic acid monomers

Nucleotides

Species

Organisms that can reproduce and produce fertile offspring

Population

Group of the same species living in one area

Community

Multiple populations living in the same area

Ecosystem

Living and nonliving components of an environment

Biome

Large region with similar climate and ecosystems

Biosphere

All living things on Earth

Biotic factors

Living components of an ecosystem

Abiotic factors

Nonliving components such as climate and weather

Climate

Long-term average weather conditions

Weather

Short-term conditions of temperature and precipitation

Factors that influence climate

Greenhouse effect, latitude, ocean currents, wind currents

Biome characteristics

Defined by temperature and precipitation

Tropical rainforest

High temperature and high precipitation

Tropical dry forest

High temperature with wet and dry seasons

Tropical grassland

High temperature, mostly dry, short wet season

Desert

High temperature and low precipitation

Temperate grassland

Mild temperatures and low precipitation

Temperate woodland

Mild temperatures and low precipitation

Temperate forest

Mild temperatures and constant precipitation

Coniferous forest

Cool to mild temperatures with wet and dry seasons

Boreal forest

Mild summers, very cold winters, low precipitation

Tundra

Cold temperatures and low precipitation

Autotroph

Organism that makes its own food

Primary producer

Autotroph that uses photosynthesis or chemosynthesis

Heterotroph

Organism that gets energy by consuming others

Consumer

Heterotroph that eats other organisms

Herbivore

Eats only producers

Carnivore

Eats only other consumers

Omnivore

Eats producers and consumers

Decomposer

Breaks down organic matter into detritus

Scavenger

Eats dead animals left by predators or other causes

10 percent rule

Only about 10% of energy transfers to the next trophic level

Food chain

Single pathway of energy transfer

Food web

Complex network of feeding relationships

Trophic level

Position an organism occupies in a food chain or web

Pyramid of energy

Shows energy available at each trophic level

Pyramid of numbers

Shows number of organisms at each trophic level

Pyramid of biomass

Shows amount of living matter at each trophic level

Water cycle processes

Evaporation, condensation, precipitation, runoff, collection

Nitrogen fixation

Bacteria convert nitrogen gas into usable forms

Denitrification

Bacteria convert nitrates into nitrogen gas

Carbon cycle photosynthesis

Plants convert carbon dioxide into oxygen

Carbon cycle respiration

Organisms release carbon dioxide

Fossil fuel combustion

Releases carbon dioxide into the atmosphere

Geographic range

Area where a population lives

Population growth rate

Births + immigration − deaths − emigration

Population density

Number of individuals per unit area

Population distribution

How individuals are spaced within a range

Age structure

Distribution of ages and sexes in a population

Factors affecting population growth

Birth rate, death rate, immigration, emigration

Exponential growth

Rapid population increase with no limiting factors

Logistic growth

Growth slows as population nears carrying capacity

Carrying capacity

Maximum population an ecosystem can support

Limiting factor

Any factor that controls population growth

Density-dependent factors

Factors that intensify as population increases

Examples of density-dependent factors

Competition, disease, predation, parasitism

Density-independent factors

Factors that affect populations regardless of size

Examples of density-independent factors

Hurricanes, droughts, floods, wildfires

Habitat

Physical area where an organism lives

Niche

Role an organism plays and how it uses resources

Competitive exclusion principle

Two species cannot occupy the same niche in the same habitat

Competition

Occurs when organisms seek the same resource

Mutualism

Both organisms benefit

Commensalism

One benefits and the other is unaffected

Parasitism

One benefits and the host is harmed

Ecosystem diversity

Variety of ecosystems in the biosphere

Species diversity

Number of different species in an area

Genetic diversity

Variation of genes within a population

Light microscope

Uses light and lenses to view specimens

Advantage of light microscopes

Can observe living specimens

Prokaryote

Cell without a nucleus

Eukaryote

Cell with a nucleus

Cell membrane

Controls what enters and leaves the cell

Nucleus

Contains genetic information

Cytoplasm

Jelly-like substance inside the cell

Mitochondria

Produces ATP through cellular respiration

Rough ER

Protein synthesis with ribosomes

Smooth ER

Lipid synthesis and detoxification

Ribosomes

Protein production