While covered gills are protected by an operculum (common in bony fish).

lobe-finned have fleshy, lobed fins that may be precursors to limbs.

• +/-: One benefits, one is harmed (predation or parasitism)

• -/-: Both are harmed (competition)

• +/0: One benefits, the other is unaffected (commensalism)

• Intraspecific: Between the same species

• Interspecific: Between different species

• Predator adaptation: Sharp teeth, good eyesight

• Prey adaptation: Camouflage, speed, warning colors

• Batesian mimicry: A harmless animal looks like a harmful one

• Mullerian mimicry: Two harmful animals look alike to warn predators

*Herbivore adaptations: Strong teeth, long digestive systems

*Plant adaptations: Thorns, toxins, bad taste

Types:

• Mutualism (+/+)

• Parasitism (+/-)

• Commensalism (+/0)

• Competition (-/-)

• Obligate: Species need each other to survive (e.g., some ants and acacia trees)

• Birth rate (natality): Number of births in a population over a period.

• Death rate (mortality): Number of deaths over a period.

• Immigration: Movement of individuals into a population.

• Emigration: Movement of individuals out of a population.

• Population density: The number of individuals per unit area or volume.

• Demographics: Statistical data related to population characteristics like age, sex, birth and death rates, etc.

Cause: Resources are unevenly distributed, or social behavior.

Example: Elephants gathering around water holes.

• Uniform Dispersion: Individuals are evenly spaced.

Cause: Territorial behavior or competition for resources.

Example: Penguins nesting at regular intervals to avoid conflict.

• Random Dispersion: Individuals are spread randomly.

Cause: Occurs in habitats where resources are consistently available and interactions are minimal.

Example: Dandelions spreading seeds by wind, landing wherever.

• Cohort: A group of individuals of the same age that are studied over time, especially to track survival and reproduction.

Type I: High Survivorship Early in Life

• Shape: Flat at the beginning (low death rates in early/mid-life), then drops steeply at older ages.

• Organisms: Humans, large mammals (like elephants, whales).

• Biological Factors:

• Parental care: Offspring are well-protected and nurtured.

• Fewer offspring: Energy is invested in ensuring survival of each.

• Low infant mortality.

• Long life spans.

Type II: Constant Death Rate

• Shape: Linear decline — equal chance of dying at any age.

• Organisms: Birds, some reptiles, rodents.

• Biological Factors:

• Moderate parental care.

• Moderate number of offspring.

• Consistent risk of predation or disease throughout life.

• Survival is not age-dependent

Type III: Low Survivorship Early in Life

• Shape: Steep drop early (many young die), then levels off for survivors.

• Organisms: Fish, insects, plants, many marine invertebrates.

• Biological Factors:

• Little to no parental care.

• High number of offspring (r-strategists).

• High infant mortality due to predation or environmental hazards.

• Those that survive early life tend to live longer.

Two most important climate variables that determine biome type:

1. Temperature

2. Precipitation

For example:

• High temp + high precipitation = Tropical rainforest

• Low temp + low precipitation = Tundra

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• The climate in a small, specific area, which can be different from the surrounding region.

• Example: The shady, cool underside of a log or a city park.

Macroclimate:

• The climate of a large area or region, like a forest, desert, or mountain range.

• Example: The general dry and hot climate of the Sahara Desert.

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• Hair or fur

• Mammary glands for lactation (feeding milk to young)

• Live birth (in most mammals)

• Warm-blooded (regulate body temperature internally)

• Three middle ear bones

• Placenta (in placental mammals)

Three Mammal Lineages:

1. Monotremes

• Lay eggs

• No nipples; milk is secreted from skin

• Examples: Platypus, echidna

• State of offspring: Very undeveloped at birth

• Unique: Only mammals that lay eggs

2. Marsupials

• Give birth to underdeveloped young

• Young develop further in a pouch

• Examples: Kangaroo, koala, opossum

• Benefit: Quick birth allows mother to escape threats; lower energy investment early on

• State of offspring: Tiny and immature; crawl to pouch after birth

3. Placental Mammals (Eutherians)

• Develop offspring internally using a placenta

• Longer gestation; young are more developed at birth

• Examples: Humans, dogs, whales, elephants

• Benefit: Offspring are more mature and independent at birth

• Hair/fur

• Mammary glands (lactation)

• Warm-blooded

• Vertebrates

Unique Traits in Primates and Humans:

• Opposable thumbs (for grasping)

• Bipedalism (walking upright on two legs in humans)

• Large brains

• Social behaviors