1. Natural Selection Notes

2. Natural Selection
The process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well-adapted individuals do.

3. Four Parts of Natural Selection
Overproduction – More offspring are born than will live to be adults
Genetic Variation Within a Population – The individuals are different. Some characteristics increase chances of survival.
Struggle to Survive – Competition for water, food, and mates; predators
Successful Reproduction – Key to natural selection – Organisms that are best adapted to their environment survive and reproduce and pass on their “good traits”

5. Changes in Genetic Variation
If a population loses many members rapidly, genetic variation is lost making the population more susceptible to disease and birth defects.

6. Florida Panther Population
Because of isolation from other populations of panthers, habitat loss, and overall decrease in population size, the genetic variation within this group has decreased.
Many surviving panthers have become genetically similar causing inbreeding within the population.
The results have been: heart defects, failure of reproductive organs, and low birth rates
A recovery program has been implemented.

7. Insecticide Resistance
When insecticides are applied, some organisms are not killed.
These surviving organisms develop an immunity to the chemicals which is passed on to their offspring.

8. Antibiotic Resistance
Occurs when bacteria is not killed by an antibiotic treatment and the bacteria mutates
This resistance to a particular antibiotic is passed from parent bacteria to offspring.
Since bacteria reproduces asexually by fission which only involves one parent, one bacterium can become 2 million in 7 hours.

9. Why have some bacteria become antibiotic resistant?
Antibiotics taken when they are not really necessary
Not following the doctors’ antibiotic directions properly
Overusing antibacterial soaps, lotions, etc.

10. Reproduction in Animals
Asexual Reproduction
Allows for no genetic variation
ALL genetic information comes from the ONE parent
Allows for many offspring in a short amount of time
Methods:
Budding (hydra)
Fragmentation (starfish)

11. Budding Hydra

12. Budding Yeast

13. Starfish

14. Sexual Reproduction
Forms offspring that are combinations of genetic material from two different parents
Female parent supplies the egg
Male parent supplies the sperm
When the egg and sperm unite, fertilization occurs and the zygote is formed

15. Fertilization of Egg

16. Genetic information is found on genes (which are located on chromosomes, made of DNA and proteins)
Allows for great amounts of genetic variation

17. Chromosomes and DNA

19. Internal or External?? Sexual reproduction can occur by:
External Fertilization
Requires a moist environment to prevent zygote from drying out
Fish and many amphibians release eggs (female) and sperm (males) into the water where they unite

20. Internal Fertilization
Egg and sperm join inside the mother’s body
Allows the female to protect the developing zygote inside her body
Reptiles, birds, and some fishes then lay the fertilized eggs and development continues outside of the mother
Development of the zygote continues inside the mother of most mammals

21. Groups of Mammals Monotremes – Egg layers; Echidnas and platypus
Marsupials – Mammals whose young complete development inside a pouch that is outside the uterus of the mother; examples -opossum, kangaroos, koalas, wombats, and Tasmanian devils
Placental Mammals – Nourished inside the mother’s body before birth and are more developed than monotremes or marsupials; over 4000 species

22. Long-Beaked Echidna

23. Platypus

24. Short-beaked Echidna

25. Marsupials

27. Placental Mammals

28. Reproduction in Plants
Nonvascular Plants
Examples – mosses, liverworts, and hornworts
Gametophytes of these plants must be covered by a film of water so sperm can swim to the eggs for fertilization to occur

29. Moss

30. Liverworts

31. Hornworts

32. Seedless Vascular Plants
Vascular plants have tissues that deliver materials from one part of the plant to another
Produce a lot of spores
Require water to reproduce
Many plants produce both eggs and sperm
Gametophytes are very small and develop on or below the surface of the soil

33. Seedless Vascular Plants - Ferns

34. Horsetails

35. Seed plant reproduction
Gymnosperms
Reproductive structures called cones
Have male and female cones
Male gametophytes = pollen (contains sperm)
Female gametophytes produce eggs
Wind transfers pollen so that fertilization occurs.
Seeds form from fertilized eggs

36. Gymnosperms

39. Angiosperms Gametophytes are within flowers
Anthers (male reproductive structure)
Stigmas (female reproductive structure)
Pollination – pollen is moved from the anthers to stigmas
Wind or animals usually help move pollen
Pollen lands on the stigma then a tube forms allowing the pollen to travel to an ovule to fertilize it

40. Angiosperms

44. From flower to Fruit
After fertilization, the ovule develops into a seed (contains young plant)
Ovary, which surrounds the ovule, becomes a fruit (which protects the seed)
Seeds are dispersed by wind, animals eating the fruit (and seeds) and releasing them in other places as wastes, or getting caught in the animal’s fur (such as burrs)

45. From Seed to Plant To sprout, most plants need: Water Air
Warm temperatures

48. Asexual Reproduction in Plants
Plantlets
Tiny plants grow along the edges of a plant’s leaves
Tubers
Underground stems (Example – Potato)
Runners
Above ground stems (Example – Strawberry)

49. Plantlets

50. Tubers

51. Runners

53. Animal Behavior

54. Kinds of Behavior Innate Does not depend on learning or experience
Inherited through genes
The male bowerbird inherits the tendency to collect colorful objects for its nest.
Puppies inherit the tendency to chew
Bees inherit the tendency to fly
Whales to swim
Some innate behaviors take time to develop (Walking in humans)

59. Kinds of Behavior (Cont’d)
Learned Behavior
Has been gathered through experience or observation
Innate behaviors can be modified through learning
Humans inherit the tendency to speak, but the language we use is learned.

60. Survival Behavior Finding Food Bees flying from flower to flower
Koala bears climbing to get Eucalyptus leaves
Chimpanzees using tools
Hunting
Animals that eat other animals are predators. The animal being eaten is the prey.
Frog  Insects; Snake Frog

61. Survival Behavior (Cont’d)
Marking Territory
Claiming territory cuts down energy spent on competing for food
Marking territories helps with mating, raising young, and food.
Birds sometimes mark their territory by the song they are singing.

62. Survival Behavior (Cont’d)
Defensive Action
Animals defend food, mates, and offspring.
They may fight or distract to defend.
Blending into the environment is a method of defense.
Outrunning predators
Chemical defense

65. Survival Behavior (Cont’d)
Courtship
Help in finding mate
Some birds and fish build nests to attract a mate
Special movements (or courtship “dances”)

68. Survival Behavior (Cont’d)
Parenting
Caterpillars begin life able to take care of themselves
Many young animals, however, depend on their parents for survival
Birds bring food to their young; killer whales spend years teaching their young to hunt for food.

76. Seasonal Behavior Migration
Moving to avoid undesirable weather conditions to find food, water, or safe nesting grounds
Whales, salmon, bats, and even chimpanzees are migratory animals
Monarch Butterflies migrate from North America to Mexico for warmer condition.
Migratory animals use landmarks (Mountain ranges, rivers, and coastlines) to help them find their way.

82. Seasonal Behavior (Cont’d)
Slowing Down
Hibernation – period of inactivity and decreased body temperature, heart rate, and breathing that some animals experience in winter.
Survive on stored body fat
Estivation – period of reduced activity during the summer
Examples - Desert Squirrels and Mice

85. Biological Clock Internal control of an animal’s natural cycles
May use clues such as day length and temperature to set their clocks
Circadian Rhythms – Daily cycles

88. Adaptations and Survival
Adaptation – characteristic that improves an individual’s ability to survive and reproduce in a particular environment.

89. Adaptations for Obtaining Food
Chameleon – long, fast-moving tongue to catch insects
Woodpecker – strong, sharply-pointed beak for drilling into trees
Humans – shape and function of our hands and fingers helps to pick and peel fruit and open jars

92. Predator-Prey Adaptations
Porcupine – Protective covering
Coral snake – Bright markings to warn predators
Bees, wasps, skunks, snakes, and poisonous frogs – warning colors
Camouflage – animal disguised to blend in with surroundings

93. Adaptations to Interactions
Mutualistic Relationship – Honeycreeper has a long, curved beak which allows it to reach in to Lobelia flower to get nectar. The bird then transfers pollen to a different flower. (Bird gets food – flower gets pollinated.)