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Natural Selection vs. Selective Breeding. Shopping PPT 7 th Grade Science. Selective Breeding. SELECTIVE BREEDING is the process of choosing parent organisms for the characteristics that we want in their offspring. Who plays a large role in this process? We do, as HUMANS! ☺.
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Natural Selection vs. Selective Breeding Shopping PPT 7th Grade Science
Selective Breeding • SELECTIVE BREEDING is the process of choosing parent organisms for the characteristics that we want in their offspring. • Who plays a large role in this process? We do, as HUMANS! ☺
Selective Breeding Examples • MATING male and female English BULLDOGS that exhibit characteristics and selling their OFFSPRING. • Farmers choosing the TRAIT they want from the CROP to breed. • SELECTIVE BREEDING can include ranchers breeding cows and buffalo to get a certain kind of meat.
It Gets Lonely in the Desert • To survive in the desert, plants must adapt to their environment. This can include: • Having short roots • Waxy coats on their leaves • Some desert plants bloom only at night because the SPECIES RELIES ON NOCTURNAL ANIMALS FOR POLLINATION.
Adapt, Adapt, Adapt! • PLANTS and ANIMALS are two types of organisms that adapt to their environments. • Adaptations helps species SURVIVE and REPRODUCE in their ENVIRONMENT. • Adaptations often evolve from a MUTATION and gave the species an ADVANTAGE.
Adapt, Adapt, Adapt! • Adaptations occur OVER TIME and can be PHYSICAL or BEHAVIORAL. • Adaptations must be common amongst a POPULATION. They CANNOT occur in just a single INDIVIDUAL. • To avoid predators, an organism might CAMOUFLAGE COLORING, LIVE IN GROUPS, and have SENSITIVE HEARING.
Adapt, Adapt, Adapt! • If body temperature rises, the adaptive response would be to SWEAT. • To survive in cold weather, humans must keep warm! One human adaptation to survive in cold weather is to GROW HAIR TO INSULATE THE HEAD.
Adapt, Adapt, Adapt! • CAMOUFLAGE is an example of an adaptation. The SNOWSHOE HARE changes its color from brown to white to blend into the snow during winter. • One adaptation of dandelions is that they are attached to stems with light, fluffy threads. This helps them DISPERSE SEEDS VIA THE WIND.
Let’s Eat! • What do you like to eat??? • Some animals, like SHARKS have very SHARP teeth to eat only MEAT. • Deer are herbivores, so their teeth are more FLAT to chew leaves or plants. • Humans are OMNIVORES, so they have both.
Natural Selection—Charles Darwin • CHARLES DARWIN’S theory of natural selection stated that individual that tend to survive have VARIATIONS BEST SUITED FOR THAT ENVIRONMENT. • Darwin studied the FINCHES on the Galapagos Islands. He noticed they had different BEAKS. They formed so the birds could EAT DIFFERENT FOODS.
Natural Selection • NATURAL SELECTION is the process that leads to the most VARIATIONS. • The Peppered Moth had a change in population caused by NATURAL SELECTION. • Natural selection is NOT the survival of the STRONGEST and BIGGEST organisms in a population.
Homeostasis • HOMEOSTASIS is the process of trying to maintain an internal stable environment despite an ever-changing external environment. • As humans, our bodies use mostly NEGATIVE feedback to maintain stability, or homeostasis.
Homeostasis • Positive feedback tends to be more RARE. An example of positive feedback would be APPLES RIPENING ON A TREE. • When apples ripen, they give off a gas called ETHLENE which causes other surrounding apples to ripen as well.
