100 facts for all 7th grade science students
ECOLOGY
1. An environment is everything, such as climate, soil, and living things, that surrounds and
affects an organism.
2. An interaction is a relationship between parts of the environment.
3. Biotic factors are the parts of the environment that are living or were once alive.
4. Abiotic factors are the parts of the environment that are nonliving.
5. A niche is the role an organism plays in its environment including its relationship with other
organisms and with its physical surroundings.
6. Habitat is the place where an organism lives.
7. An ecosystem is a group of organisms and their physical environment.
8. Symbiosis is a kind of partnership between two organisms in nature.
9. Commensalism is a symbiotic relationship between two organisms in which
one benefits and the other neither benefits nor is harmed.
10. Mutualism is a symbiotic relationship between two organisms in which both
benefit.
11. Parasitism is a symbiotic relationship in which one organism benefits (the parasite)
and the other organism (the host) is harmed.
12. The process of using sunlight, water and carbon dioxide to make food (glucose)
used by green plants is called photosynthesis.
13. Organisms that produce food for themselves and others are called producers.
14. Organisms that depend on other organisms for food are called consumers.
15. Consumers of only plants are called herbivores.
16. Consumers of only meat are called carnivores.
17. Consumers that eat both plants and animals are called omnivores.
18. A consumer that hunts or captures other organisms (prey) for food
is called a predator.
19. An organism that is hunted or captured and eaten by another consumer is called prey.
20. A scavenger is a consumer of dead or decaying plants and animals. For example, an
earthworm is a scavenger because it eats dead organic matter.
21. Bacteria and fungi that break down dead and decaying plant and animal matter which
enriches the soil are called decomposers.
22. All organisms of the same species living in the same area is known as a population.
23. All the populations of species living in an area is known as a community.
24. A diagram showing how certain living things depend on one another for energy is known as
a food chain.
25. A diagram showing as many food relationships as possible between living things is known
as a food web.
26. Changes in an area that cause one group of organisms to be replaced by another is called
succession.
27. A non-native species of plant or animal that out-competes native species in a specific habitat
is called an invasive species. Purple loosestrife, Japanese beetle, garlic mustard, and
zebra mussels are examples of invasive species.
28. Acid rain is precipitation formed when pollution from burning gas, oil, or coal mix with
water vapor in the air to form an acid.
29. The pH scale is a rating scale used to measure the acid or alkaline (base) content of a
substance. It ranges from 0 to 14.
30. A substance with a pH of less than 7 is an acid. A substance with a pH of greater than 7 is a
base. Substances with a pH of 7 are considered neutral.
GENETICS
31. DNA (Deoxyribonucleic Acid) is the chemical compound that codes all life. It is made up of
two twisted strands of sugar, phosphate and nitrogen bases.
32. A gene is a section of DNA on a chromosome that contains instructions for making specific
proteins.
33. A chromosome is a structure in a cell’s nucleus that contains hereditary material.
34. Gregor Mendel was an Austrian monk who is considered the Father of Genetics. He lived
and worked in the 19th century. He is known especially for his work with pea plants.
35. The term heredity refers to the passing of traits from parent to offspring.
36. An allele is an alternate form that a gene may have for a single trait. It can be dominant or
recessive.
37. Genetics is the study of how traits are inherited through the actions of alleles.
38. An offspring that was given different genetic information for a trait from each parent is
called a hybrid.
39. The term dominant describes a trait that covers over, or dominates, another form of that trait.
40. The term recessive describes a trait that is covered over, or dominated, by another form of
that trait and seems to disappear.
41. A Punnett square is a tool used to predict the probability of certain traits in offspring that
shows the different ways alleles can combine.
42. Genotype is the gene makeup of a specific trait.
43. Phenotype is the outward physical appearance and behavior of an organism as a result of its
genotype.
44. Homozygous describes an organism with two alleles that are the same for a trait.
45. Heterozygous describes an organism with two different alleles for a trait.
BIODIVERSITY
46. The term diversity describes the different characteristics in living things.
47. Scientists use the term organism to describe any living thing.
48. Jean Baptiste de Lamarck was a scientist who believed that if organisms acquired a
characteristic during their lifetime, it could be passed on to future generations. He died in
1829 when Darwin was 20 years old.
49. In the 19th century, Charles Darwin developed the Theory of Natural Selection. This theory
explains how the characteristics of a species can change over many generations so it is
better suited to its environment.
50. An English scientist named H.B.D. Kettlewell conducted an experiment in the 1950’s with
peppered moths. The results of this famous experiment supported Darwin’s theory.
51. Adaptations are inherited features that enable organisms to survive and produce young.
52. Camouflage is an adaptation that enables an organism to blend in with its environment.
53. Mimicry is an adaptation in which one organism gains protection by looking like another
type of organism that predators avoid because of its undesirable smell, taste or sting.
54. Appendages are structures that attach to the main body of an organism. Arms, legs, fins and
tails are all examples of appendages.
55. A species that is near extinction and may not survive in the wild unless it is protected is
called an endangered species.
56. Extinction is the dying out of a species.
57. An animal with a backbone is called a vertebrate.
58. An animal without a backbone is called an invertebrate.
59. Carolus Linnaeus was a Swedish scientist who lived in the 18th century. He devised a
scientific system for classifying living things according to their structure and anatomy.
System still used today.
60. An organism’s scientific name is a combination of its genus and species. The scientific name
for man is: Homo sapiens.
ROCKS AND LANDFORMS
61. Igneous rocks are rocks that have solidified from molten or partly molten materials (magma).
62. Metamorphic rocks are rocks that have been changed (metamorphosed) into a different rock
type, without actually melting, by an increase in temperature and/or pressure, and/or the
action of chemical fluids.
63. Sedimentary rocks are rocks that are usually layered and are the result of consolidation or
lithification of sediment.
64. The rock cycle is a sequence of processes or events involving the formation, alteration,
destruction, and reformation of rocks as the result of such processes as uplift, erosion,
deposition, melting, crystallization, and metamorphism.
65. A landform is a part or area of the Earth’s surface that has a distinctive shape or topography.
Some landforms would be: plains, plateaus, mountain ranges, hills, valleys, and canyons.
66. Weathering is a series of natural processes, both physical and chemical, that act to change
exposed rock into mineral and rock particles and chemical compounds in solution.
67. An independent variable (cause) is the one variable that is changed on purpose in an
experiment.
68. A dependent variable (effect) is the outcome that is being measured in an experiment.
PLANTS
69. Brassica rapa is the scientific name for the Wisconsin Fast Plant.
70. Four main stages of growth of the Wisconsin Fast Plant are: appearance of the cotyledons,
emergence of the true leaves, appearance of flowers, and the appearance of seedpods.
71. The term germination means any evidence of growth (sprouting).
72. Roots are the part of the plant below the ground that hold the plant in place and feeds the
plant.
73. Root hairs are located on the root; they draw in water and minerals from the soil.
74. A seed has an embryo of a plant inside it that has the potential to become a mature plant.
75. A cotyledon, also know as a seed leaf, helps to absorb food (nutrients) for the seedling until
the plant can photosynthesize.
76. Pollination is the process of moving pollen from one plant to another plant (crosspollination) or from one part to another part of the same plant (self-pollination). Bees and
other insects help pollinate flowers. They can carry the pollen on their body parts: head,
thorax and abdomen.
77. The term hydroponics refers to growing plants without soil by using solutions to provide the
necessary nutrients for growth.
78. Geotropism is a plant’s growth reaction to the force of gravity. Roots demonstrate a positive
geotropic response because they grow towards the stimulus (pull of gravity). Stems
demonstrate a negative geotropic response because they grow away from the stimulus.
79. Heliotropism is a plant’s growth response to sunlight. Plants growing towards sunlight
demonstrate a positive heliotropic response.
80. Phototropism is a plant’s growth response to light – any kind of light, natural or artificial.
Plants growing towards light demonstrate a positive phototropic response.
81. Flowers are the colorful part of the plant that attracts bees (pollinators).
82. The sepal is the outer part that protects the flower as it is developing.
83. The stamen is the male part of the flower that is made up of the anther and filament. This is
the part of the plant that produces pollen.
84. Anther is the top part of the stamen that contains the pollen.
85 The filament is the stalk of the stamen. It attaches it to the center of the flower.
86. The pistil is the female part located in the center of the flower. It contains the stigma, style
and ovary.
87. The stigma is the top, flat part of the pistil that the pollen needs to stick to when pollination
occurs.
88. The style is the skinny (middle) part of the pistil made of tissue that surrounds and protects
the pollen tube.
89. The ovary is the bottom part of the pistil that contains the ovules. Sometimes the ovary
develops into a fruit.
90. The ovule is the part of the plant that holds the egg.
91. The pedicel is the stem of the flower.
92. The petal is the part of the flower that is colored.
93. NPK rating indicates the percentage of three chemicals present in a fertilizer. The chemicals
are: Nitrogen, Phosphorus and Potassium.
94. Humus is the part of fertile soil derived from the decomposition of living things.
95. The feel of the soil is known as its texture.
96. Loam is a mixture of 40% sand, 40% silt, and 20% clay.
97. Nutrients are chemicals needed for plant functioning and growth.
98. Gymnosperms are plants without flowers or fruits.
99. Angiosperms are plants with flowers and fruits.
100. Monocots are plants with one cotyledon. Dicots are plants with two cotyledons.