Heredity and Diversity Chapter 2 Heredity and Diversity

Lesson 2 Traits and Heredity

What is heredity? Heredity is the passing down of traits from parents to offspring. Inherited trait is a trait that an offspring receives from its parents. Examples of inherited traits in humans: dimples, hair and eye color, facial features.

What is heredity? An instinct is a way of acting or behaving that an animal is born with and does not have to learn. Example of instinct: a spider spinning a web. Some behaviors are learned and not inherited. The ability to learn helps animals to survive and to respond to changes in their environment.

How are traits inherited? Traits are controlled by two factors and the animal/plant receives one factor from each parent. These factors are called genes. A gene contains chemical instructions for inherited traits. All inherited traits are either dominant or recessive.

How are traits inherited? A dominant trait is one that dominates another form of that trait. A recessive trait is one that is hidden by another form of the trait. Traits are represented by letters. A capital letter represents a dominant trait and a lower case letter represents a recessive trait.

How are traits inherited? Recessive traits are covered up by dominant traits even if an organism has the recessive trait.

How do we trace inherited traits? A pedigree is a chart used to trace the history of traits in a family. A carrier is any individual who has inherited the gene for a trait but does not show the trait physically. Look at page 104 at the pedigree chart.

Animal Adaptations for Survival Lesson 3 Animal Adaptations for Survival

What is adaptation? An adaptation is any characteristic that helps an organism survive in its environment. Animals with successful adaptations have a higher chance of survival than other organisms. Physical adaptation are adjustments to internal and external structures.

What is adaptation? Fur color, long limbs, and strong jaws are physical adaptations. Groups of animals share similar adaptations. Reptiles have dry, scaly skin and lay eggs with soft, leathery shells. Amphibians return to water to lay their eggs.

What is adaptation? Birds have hallow bones to reduce their weight for flight. Mammals have fur or hair and produce milk to feed their young. As a class, list some physical adaptations and why they are important.

What are behavioral adaptations? An adjustment in an organism’s behavior is a behavioral adaptation. These adaptations help animals find food or defend themselves. Some animals travel in groups for safety or hunting. Some animals only come out at night, which is called being nocturnal.

What are behavioral adaptations? Some have adaptations to help them attract mates. Example: crickets chirp by rubbing their wings together.

What are adaptations to climate? In hot climates, animals must be able to get rid of excess heat or store extra food and water. In colder climates, animals must reduce heat loss. Most animals have insulation.

What are adaptations to climate? Some animals have adaptations to help them survive seasonal changes. Some birds, butterflies, and fish migrate to a warmer climate during colder seasons. Some animals hibernate during cold weather in order to survive.

What adaptations do predators and prey have? How prey escape Use chemical to escape predators: skunks spray and some snakes have poison glands Run at very fast speeds Play dead How predators catch prey Giant anteaters have long tongues to get ants

What adaptations do predators and prey have? Woodpeckers have long, pointed beaks to get insects out of trees. Some animas increase chances of survival by blending into their surroundings. Any coloring, shape, or pattern that allows an organisms to blend in with its environment is called camouflage.

What adaptations do predators and prey have? Camouflage helps predators and prey. Protective coloration is a type of camouflage in which the color of an animal helps it blend in with its background. Protective resemblance is when an animal matches the color, shape , and texture of the environment.

What is mimicry? An adaptation in which an animal is protected against predators by its resemblance to an unpleasant animal is called mimicry. Example: the viceroy butterfly is protected because it looks just like the bad-tasting, poisonous monarch butterfly.

What is mimicry? Predators also use mimicry by deceiving their prey. Example: snapping turtles have the ability to wag a “lure” in their mouth that looks like a worm. Fish come to try to eat the “worm” and the turtle catches the fish.

Lesson 4 Change over Time

What are variations? Variations are differences among members of the same species that enables individuals to better survive and reproduce. A mutation is a change in an organism’s genetic material. These successful variations will be passed down to the animals offspring.

What is natural selection? Organisms that are best able to obtain food and escape from predators survive and reproduce. These organisms will reproduce more offspring. More offspring means that there is more competition in an area usually resulting with the successful animal surviving.

What is natural selection? Natural selection occurs when the organisms that are best suited to their environments survive and reproduce successfully. Natural selection is also called “survival of the fittest”

What is evidence of change over time? The history of changes throughout time can be found in the millions of fossils collected by scientists. Fossils are the remains, traces, or imprints of living things preserved in Earth’s crust.

What is evidence of change over time? Ways fossils form A dead organism is covered quickly by sediment and minerals replace hard parts of the organism. Insects might get stuck in tree sap Organisms can leave imprints in soft rock or sand. It dries quickly and is covered up by sediment. Animals can be preserved in the ooze of tar pits or frozen in ice.

What is evidence of change over time? What fossils tell us They tell what the environment was like long ago They tell what the climate was like in an area They tell what organisms were like in the past and how they compare to today’s organisms

How old are fossils? The law of superposition says that each rock layer is older than the layer above it and younger than the layer below it. If one fossil was in a rock layer above another fossil in a lower rock layer, then the relative age of the lower layer fossil is older than the higher layer fossil.

How old are fossils? Relative age of a rock is how old it is compared to another rock. Absolute age is the age of a fossil in years. When describing the age of the Earth, scientists use units called eras. An era is a unit of time measured in millions of years.

How old are fossils? Each era is described by the kinds of life that were dominant in that era. Eras are split into periods that are shorter amounts of time. Periods are associated with major changes in the Earth’s crust.