Animal adaptations
Outline:• Acquisition of energy and nutrients• Respiration• Homeostasis• Water balance• Biological rhythms
• Readings: Chapter 7
Energy and nutrient acquisition
Detritivores
Herbivores
Types of herbivores
• Grazers - leaf tissue
• Browsers - woody tissue
• Granivores - seeds
• Frugivores - fruit
• Nectivores - nectar
• Phloem feeders - sap
• High cellulose (fiber), low protein
• Animals can’t digest cellulose (no cellulase enzymes)
• Need symbiotic bacteria, protozoa
Ruminants(e.g. cows, sheep, deer)
Non-ruminants(e.g. rabbits, horses)
Coprophagy
= ingestion of feces
• E.g. Lagomorphs (rabbits, hares & pikas)
• E.g. Detritivores
N and food quality
• For herbivores, food quality increases with increasing N content
• In animals, C:N ~ 10:1
• In plants, C:N ~ 40:1 herbivores limited by N availability– Highest in growing stems, leaves, buds– Decreases as plant agesHerbivores usually born in spring
Carnivores
• Composition of food similar to own tissues--> simple stomach --> small caecum
• Need to get enough food
Omnivores
• Feed on > 1 trophic level, e.g. plants and herbivores
• Diet varies with season, life cycle
Diet breadth
1. Generalists: “polyphagous” – eat >1 prey species
2. Specialists: “monophagous” – eat one prey species – or eat specific part of prey
• E.g. seed-eating birds
• Specialists are usually• Short-lived (active only when food is available)• Highly adapted to a specific food type (can’t use
any other)
C6H12O6 + 6O2 6CO2 + 6H2O + ATP
RESPIRATION
HOMEOSTASIS
THERMOREGULATION
TEMPERATUREREGULATION
TYPE OF HEAT PRODUCTION:Endothermy: - heat from withinEctothermy: - heat from withoutHeterothermy - employ endo and ectothermy in different situations
TEMPERATURE VARIATION:Homeothermy - constant temperaturePoikilothermy - variable temperature
TEMPERATURE REGULATION poikilotherms
TEMPERATURE REGULATION poikilotherms
Operative temperature range
TEMPERATURE REGULATION poikilotherms
Acclimatization
Lizards and snakes: body temperature varies only 4-5oC/day
TEMPERATURE REGULATION poikilotherms
TEMPERATURE REGULATION homeotherms
Endothermy – ectothermy tradeoffs
Endothermy tradeoff
Because of their small size (high surface: volume ratio) and their need to invest energy in growth, juvenile birds and mammals are often ectothermic, obtaining heat from their parents.
Conserving energy – ectothermy for juveniles
Bears are not true hibernators; their body temperature drops only a few degrees, and they are relatively easily awakened
Conserving energy – hibernation
Conserving energy – countercurrent heat exchange
without
with
Releasing energy – countercurrent heat exchange
RETE
Adaptations to aridity and heat
Water balance in aquatic environments
• Freshwater organisms: hyperosmotic (water wants to move inside of organism
• Marine organisms: hypoosmotic (water wants to move outside of organism
Controls on activity
Human diurnal cycle
Life history strategies
Outline:• Types of reproduction• Mating systems• Sexual selection• Energy and timing of reproduction• Offspring• Habitat selection• Environmental influences•
Readings: Ch. 8
A simple life history
Life history = schedule of birth, growth, reproduction & death
Types of reproduction
• Asexual or sexual
• Different forms of sexual reproduction
Simultaneous hermaphrodites
Sex change
Mating system
• Strength of bond:– Monogamy (strong) - Promiscuity (no bond)
• Types of bonds:– Monogamy (one-to-one)– Polygamy (one-to-many)
• Polygyny (one male, many females)• Polyandry (one female, many males)
POLYANDRY: African Jacana
Sexual selection
• Intrasexual selection – male-to-male or female-to-female competition for the opportunity to mate
Sexual selection
• Intersexual selection – differential attractiveness of individuals
Reproduction is costly
Timing of reproduction
• Semelparity - reproduce once and die
• Iteroparous - reproduce throughout lifetime
European grasshopper, Chorthippus brunneus
An iteroparous summer annual
Pigweed, Chenopodium album
A semelparous summer annual
Semelparous perennials
Coho salmon: a long-lived semelparous animal• Dies after spawning (2-5 yrs)• Overlapping generations
Bamboo• Both genets and ramets are semelparous. • Genets can live for 200 years before the simultaneous flowering of all
ramets.
Semelparous perennials
Parental investment
Fecundity
Fecundity
Reproductive tradeoffs
Reproductive tradeoffs
Reproductive tradeoffs
Reproductive tradeoffs
r and K strategists
For next lecture:
• Please read Chapter 9, 10, 11, 12
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