Adaptation and Variation

1. Adaptation and Variation SBI3U Section 7.1 Pg 296-304

2. Adaptation • Adaptation is a structure, behaviour or physiological process that helps an organism survive and reproduce in a particular environment Eg. Camouflage is a structural adaptation that allows an organism to blend in to its environment to evade predators or sneak up on prey

3. Structural Adaptation • A physical or structural trait that aids survival and reproductive success

4. Structural Adaptations: Saiga • The saiga has an odd shaped nose. • When it breathes, cool air is circulated in its large nasal cavity, warming the air Why do you think we have such a big nose?

5. Camouflage How does the camouflage in this tiger help it survive?

6. Structural Adaptations: Snowshoe hare Turn white in winter to camouflage Large feet act as snowshoes Can you explain adaptations of the snowshoe hare?

7. Structural Adaptation: King Vulture Featherless head allows it to enter its head into carcasses, and not get stuck on the way out

8. Mimicry: A type of structural Adaptation • Mimicry is a structural adaptation in which a one species resembles another species in coloration or structure

9. Mimicry • A structural adaptation in which a harmless species resembles a harmful species in coloration, structure, or movement The blue jay, after eating the monarch, promptly vomit it because of a bad taste. The viceroy, by looking like the inedible monarch, avoids predation from predators.

10. Mimicry: Katydid • The katydid mimics a dead leaf to remain unseen

11. Mimicry: Orchid Mantis • The orchid mantis, which resembles the orchid flower, hides amongst orchid flowers waiting for its prey (other insects)

12. Mimicry: Coral Snakes • The eastern coral snake is venomous, and displays warning coloration • The scarlet king snake is a non-venomous snake

13. Behavioural Adaptations • Are actions or types of behaviour that give organisms the best chance to survive

14. Behavioral Adaptations • Nocturnal animals – awake at night, conserve energy and avoid overheating during the day, protection of darkness • Migratory animals – animals migrate to areas with abundant nutrients at different times of year, or for mating

15. Physiological Adaptation • A systematic response of an individual to a specific external stimulus in order to maintain homeostasis or a metabolic adjustment within the cell or tissues of an organism in response to an environmental stimulus resulting in the improved ability of the organism to cope with its changing environment. • Eg. tanning of skin when exposed to sun is a response of the individual to sunlight which is an external stimulus. The skin releases the pigment melanin which absorbs UV rays thus protecting the skin.

16. Physiological Adaptation • Many animals hibernate in cold months which reduce their metabolism allowing them to conserve energy

17. Physiological Adaptations: Venom • Venomous animals make venom for defense • Often accompanied with warning colouration

18. Development of Adaptations • Adaptations develop through mutations in DNA that can be passed on and accumulate over generations • Variations are structural, functional or physiological differences between individuals and are only considered as adaptations if they help the organism survive • Mutations are changes in genetic material (DNA) of an organism and can be harmful (cancer) or provide the organism a genetic advantage over its competitors for survival (selective advantage) • In order for a mutation to be passed on to future generations it must alter the DNA in a gamete

19. The Peppered Moth • The English peppered moth (Bistonbetularia) has three phenotypes: • Greyish white with black spots (pepper) • Black (melanic) • Intermediate colour (not shown)

20. Environmental change • In 1840’s England, melanic moths represented less than 2% of moths • Within 50 years, 95% of moths in urban areas were melanic • In rural areas, melanic moths are less frequent • What environmental change could have caused this?

22. Pollution • Peppered moths: • Active at night • During the day they rest on leaves and tree trunks • Lichen covered trees provide camouflage for pepper coloured moth • Soot from factories darkened trees, providing camouflage for melanic moths • Frequency of melanic alleles increased in population • Individual moths did not change from peppered to melanic

23. Antibiotic Resistant Bacteria an example of Selective Advantage • Bacteria reproduce very quickly thus allowing for a large genetic variation in the population thus helping adaptation occur very quickly • When an antibiotic is introduced to the bacteria’s environment some bacteria may have a resistance to the antibiotic (due to a mutation) and survive while the bacteria without the resistance will die out • The surviving bacteria will multiply producing offspring that also have the same resistance to the antibiotic

24. NATURAL SELECTION AND ARTIFICIAL SELECTION SBI3U Section 7.2 Pg 305-311

25. Natural Selection • Is the process that results when the characteristics of a population of organisms change over many generations • This change happens because individuals with certain inherited traits survive specific local environmental conditions and through reproduction pass on their alleles to their offspring • For natural selection to occur there must be diversity within a population so that there will be a wide variety of alleles within the population that could provide an advantage for survival to certain environmental conditions

26. Selective Pressure • Environmental conditions that favour certain characteristics in some individuals and do not favour characteristics in other individuals exert a selective pressure on a population • Selective pressure may result from abiotic (non-living) factors such as climate or habitat or biotic (living) factors such as predators, parasites and competition for resources

27. Eg. Certain environments may favour certain beak structure in the below birds. A long narrow beak may favour birds who’s prey can hide in tight places or a shorter thicker beak may favour birds who’s prey are larger and have a hard exoskeleton.

28. Fitness The relative contribution an individual makes to the next generation by producing offspring that will survive long enough to reproduce

29. Which is more fit? Does it matter if the offspring can reproduce?

30. How did we get so many different types of dogs?

31. Artificial Selection • Artificial Selection – When the selective pressure is exerted by humans • Human desired traits • Agriculture – food crops, food animals • Domesticated animals – dogs, cats, horses

32. What do the following have in common: • Kohlrabi • Kale • Broccoli • Brussels sprouts’ • Cabbage • Cauliflower The wild mustard plant has been modified by selective breeding to create many common food crops

33. This graph shows the results of selective breeding for oil content in plants. In this example two populations of corn plants were separated out. One population of corn plants were selectively bred for high oil content in their kernels and one population was selectively bred for low oil content in their kernels